2 * @brief memory-mapped database library
4 * A Btree-based database management library modeled loosely on the
5 * BerkeleyDB API, but much simplified.
8 * Copyright 2011-2013 Howard Chu, Symas Corp.
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted only as authorized by the OpenLDAP
15 * A copy of this license is available in the file LICENSE in the
16 * top-level directory of the distribution or, alternatively, at
17 * <http://www.OpenLDAP.org/license.html>.
19 * This code is derived from btree.c written by Martin Hedenfalk.
21 * Copyright (c) 2009, 2010 Martin Hedenfalk <martin@bzero.se>
23 * Permission to use, copy, modify, and distribute this software for any
24 * purpose with or without fee is hereby granted, provided that the above
25 * copyright notice and this permission notice appear in all copies.
27 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
28 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
29 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
30 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
31 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
32 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
33 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
38 #include <sys/types.h>
40 #include <sys/param.h>
46 #ifdef HAVE_SYS_FILE_H
63 #if !(defined(BYTE_ORDER) || defined(__BYTE_ORDER))
64 #include <netinet/in.h>
65 #include <resolv.h> /* defines BYTE_ORDER on HPUX and Solaris */
68 #if defined(__APPLE__) || defined (BSD)
69 # define MDB_USE_POSIX_SEM 1
70 # define MDB_FDATASYNC fsync
71 #elif defined(ANDROID)
72 # define MDB_FDATASYNC fsync
77 #ifdef MDB_USE_POSIX_SEM
78 #include <semaphore.h>
83 #include <valgrind/memcheck.h>
84 #define VGMEMP_CREATE(h,r,z) VALGRIND_CREATE_MEMPOOL(h,r,z)
85 #define VGMEMP_ALLOC(h,a,s) VALGRIND_MEMPOOL_ALLOC(h,a,s)
86 #define VGMEMP_FREE(h,a) VALGRIND_MEMPOOL_FREE(h,a)
87 #define VGMEMP_DESTROY(h) VALGRIND_DESTROY_MEMPOOL(h)
88 #define VGMEMP_DEFINED(a,s) VALGRIND_MAKE_MEM_DEFINED(a,s)
90 #define VGMEMP_CREATE(h,r,z)
91 #define VGMEMP_ALLOC(h,a,s)
92 #define VGMEMP_FREE(h,a)
93 #define VGMEMP_DESTROY(h)
94 #define VGMEMP_DEFINED(a,s)
98 # if (defined(_LITTLE_ENDIAN) || defined(_BIG_ENDIAN)) && !(defined(_LITTLE_ENDIAN) && defined(_BIG_ENDIAN))
99 /* Solaris just defines one or the other */
100 # define LITTLE_ENDIAN 1234
101 # define BIG_ENDIAN 4321
102 # ifdef _LITTLE_ENDIAN
103 # define BYTE_ORDER LITTLE_ENDIAN
105 # define BYTE_ORDER BIG_ENDIAN
108 # define BYTE_ORDER __BYTE_ORDER
112 #ifndef LITTLE_ENDIAN
113 #define LITTLE_ENDIAN __LITTLE_ENDIAN
116 #define BIG_ENDIAN __BIG_ENDIAN
119 #if defined(__i386) || defined(__x86_64) || defined(_M_IX86)
120 #define MISALIGNED_OK 1
126 #if (BYTE_ORDER == LITTLE_ENDIAN) == (BYTE_ORDER == BIG_ENDIAN)
127 # error "Unknown or unsupported endianness (BYTE_ORDER)"
128 #elif (-6 & 5) || CHAR_BIT != 8 || UINT_MAX < 0xffffffff || ULONG_MAX % 0xFFFF
129 # error "Two's complement, reasonably sized integer types, please"
132 /** @defgroup internal MDB Internals
135 /** @defgroup compat Windows Compatibility Macros
136 * A bunch of macros to minimize the amount of platform-specific ifdefs
137 * needed throughout the rest of the code. When the features this library
138 * needs are similar enough to POSIX to be hidden in a one-or-two line
139 * replacement, this macro approach is used.
143 #define MDB_PIDLOCK 0
144 #define pthread_t DWORD
145 #define pthread_mutex_t HANDLE
146 #define pthread_key_t DWORD
147 #define pthread_self() GetCurrentThreadId()
148 #define pthread_key_create(x,y) \
149 ((*(x) = TlsAlloc()) == TLS_OUT_OF_INDEXES ? ErrCode() : 0)
150 #define pthread_key_delete(x) TlsFree(x)
151 #define pthread_getspecific(x) TlsGetValue(x)
152 #define pthread_setspecific(x,y) (TlsSetValue(x,y) ? 0 : ErrCode())
153 #define pthread_mutex_unlock(x) ReleaseMutex(x)
154 #define pthread_mutex_lock(x) WaitForSingleObject(x, INFINITE)
155 #define LOCK_MUTEX_R(env) pthread_mutex_lock((env)->me_rmutex)
156 #define UNLOCK_MUTEX_R(env) pthread_mutex_unlock((env)->me_rmutex)
157 #define LOCK_MUTEX_W(env) pthread_mutex_lock((env)->me_wmutex)
158 #define UNLOCK_MUTEX_W(env) pthread_mutex_unlock((env)->me_wmutex)
159 #define getpid() GetCurrentProcessId()
160 #define MDB_FDATASYNC(fd) (!FlushFileBuffers(fd))
161 #define MDB_MSYNC(addr,len,flags) (!FlushViewOfFile(addr,len))
162 #define ErrCode() GetLastError()
163 #define GET_PAGESIZE(x) {SYSTEM_INFO si; GetSystemInfo(&si); (x) = si.dwPageSize;}
164 #define close(fd) (CloseHandle(fd) ? 0 : -1)
165 #define munmap(ptr,len) UnmapViewOfFile(ptr)
166 #ifdef PROCESS_QUERY_LIMITED_INFORMATION
167 #define MDB_PROCESS_QUERY_LIMITED_INFORMATION PROCESS_QUERY_LIMITED_INFORMATION
169 #define MDB_PROCESS_QUERY_LIMITED_INFORMATION 0x1000
176 /** For MDB_LOCK_FORMAT: True if readers take a pid lock in the lockfile */
177 #define MDB_PIDLOCK 1
179 #ifdef MDB_USE_POSIX_SEM
181 #define LOCK_MUTEX_R(env) mdb_sem_wait((env)->me_rmutex)
182 #define UNLOCK_MUTEX_R(env) sem_post((env)->me_rmutex)
183 #define LOCK_MUTEX_W(env) mdb_sem_wait((env)->me_wmutex)
184 #define UNLOCK_MUTEX_W(env) sem_post((env)->me_wmutex)
187 mdb_sem_wait(sem_t *sem)
190 while ((rc = sem_wait(sem)) && (rc = errno) == EINTR) ;
195 /** Lock the reader mutex.
197 #define LOCK_MUTEX_R(env) pthread_mutex_lock(&(env)->me_txns->mti_mutex)
198 /** Unlock the reader mutex.
200 #define UNLOCK_MUTEX_R(env) pthread_mutex_unlock(&(env)->me_txns->mti_mutex)
202 /** Lock the writer mutex.
203 * Only a single write transaction is allowed at a time. Other writers
204 * will block waiting for this mutex.
206 #define LOCK_MUTEX_W(env) pthread_mutex_lock(&(env)->me_txns->mti_wmutex)
207 /** Unlock the writer mutex.
209 #define UNLOCK_MUTEX_W(env) pthread_mutex_unlock(&(env)->me_txns->mti_wmutex)
210 #endif /* MDB_USE_POSIX_SEM */
212 /** Get the error code for the last failed system function.
214 #define ErrCode() errno
216 /** An abstraction for a file handle.
217 * On POSIX systems file handles are small integers. On Windows
218 * they're opaque pointers.
222 /** A value for an invalid file handle.
223 * Mainly used to initialize file variables and signify that they are
226 #define INVALID_HANDLE_VALUE (-1)
228 /** Get the size of a memory page for the system.
229 * This is the basic size that the platform's memory manager uses, and is
230 * fundamental to the use of memory-mapped files.
232 #define GET_PAGESIZE(x) ((x) = sysconf(_SC_PAGE_SIZE))
235 #if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
238 #define MNAME_LEN (sizeof(pthread_mutex_t))
244 /** A flag for opening a file and requesting synchronous data writes.
245 * This is only used when writing a meta page. It's not strictly needed;
246 * we could just do a normal write and then immediately perform a flush.
247 * But if this flag is available it saves us an extra system call.
249 * @note If O_DSYNC is undefined but exists in /usr/include,
250 * preferably set some compiler flag to get the definition.
251 * Otherwise compile with the less efficient -DMDB_DSYNC=O_SYNC.
254 # define MDB_DSYNC O_DSYNC
258 /** Function for flushing the data of a file. Define this to fsync
259 * if fdatasync() is not supported.
261 #ifndef MDB_FDATASYNC
262 # define MDB_FDATASYNC fdatasync
266 # define MDB_MSYNC(addr,len,flags) msync(addr,len,flags)
277 /** A page number in the database.
278 * Note that 64 bit page numbers are overkill, since pages themselves
279 * already represent 12-13 bits of addressable memory, and the OS will
280 * always limit applications to a maximum of 63 bits of address space.
282 * @note In the #MDB_node structure, we only store 48 bits of this value,
283 * which thus limits us to only 60 bits of addressable data.
285 typedef MDB_ID pgno_t;
287 /** A transaction ID.
288 * See struct MDB_txn.mt_txnid for details.
290 typedef MDB_ID txnid_t;
292 /** @defgroup debug Debug Macros
296 /** Enable debug output. Needs variable argument macros (a C99 feature).
297 * Set this to 1 for copious tracing. Set to 2 to add dumps of all IDLs
298 * read from and written to the database (used for free space management).
304 static int mdb_debug;
305 static txnid_t mdb_debug_start;
307 /** Print a debug message with printf formatting.
308 * Requires double parenthesis around 2 or more args.
310 # define DPRINTF(args) ((void) ((mdb_debug) && DPRINTF0 args))
311 # define DPRINTF0(fmt, ...) \
312 fprintf(stderr, "%s:%d " fmt "\n", __func__, __LINE__, __VA_ARGS__)
314 # define DPRINTF(args) ((void) 0)
316 /** Print a debug string.
317 * The string is printed literally, with no format processing.
319 #define DPUTS(arg) DPRINTF(("%s", arg))
322 /** A default memory page size.
323 * The actual size is platform-dependent, but we use this for
324 * boot-strapping. We probably should not be using this any more.
325 * The #GET_PAGESIZE() macro is used to get the actual size.
327 * Note that we don't currently support Huge pages. On Linux,
328 * regular data files cannot use Huge pages, and in general
329 * Huge pages aren't actually pageable. We rely on the OS
330 * demand-pager to read our data and page it out when memory
331 * pressure from other processes is high. So until OSs have
332 * actual paging support for Huge pages, they're not viable.
334 #define MDB_PAGESIZE 4096
336 /** The minimum number of keys required in a database page.
337 * Setting this to a larger value will place a smaller bound on the
338 * maximum size of a data item. Data items larger than this size will
339 * be pushed into overflow pages instead of being stored directly in
340 * the B-tree node. This value used to default to 4. With a page size
341 * of 4096 bytes that meant that any item larger than 1024 bytes would
342 * go into an overflow page. That also meant that on average 2-3KB of
343 * each overflow page was wasted space. The value cannot be lower than
344 * 2 because then there would no longer be a tree structure. With this
345 * value, items larger than 2KB will go into overflow pages, and on
346 * average only 1KB will be wasted.
348 #define MDB_MINKEYS 2
350 /** A stamp that identifies a file as an MDB file.
351 * There's nothing special about this value other than that it is easily
352 * recognizable, and it will reflect any byte order mismatches.
354 #define MDB_MAGIC 0xBEEFC0DE
356 /** The version number for a database's datafile format. */
357 #define MDB_DATA_VERSION 1
358 /** The version number for a database's lockfile format. */
359 #define MDB_LOCK_VERSION 1
361 /** @brief The maximum size of a key in the database.
363 * The library rejects bigger keys, and cannot deal with records
364 * with bigger keys stored by a library with bigger max keysize.
366 * We require that keys all fit onto a regular page. This limit
367 * could be raised a bit further if needed; to something just
368 * under #MDB_PAGESIZE / #MDB_MINKEYS.
370 * Note that data items in an #MDB_DUPSORT database are actually keys
371 * of a subDB, so they're also limited to this size.
373 #ifndef MDB_MAXKEYSIZE
374 #define MDB_MAXKEYSIZE 511
377 /** @brief The maximum size of a data item.
379 * We only store a 32 bit value for node sizes.
381 #define MAXDATASIZE 0xffffffffUL
386 * This is used for printing a hex dump of a key's contents.
388 #define DKBUF char kbuf[(MDB_MAXKEYSIZE*2+1)]
389 /** Display a key in hex.
391 * Invoke a function to display a key in hex.
393 #define DKEY(x) mdb_dkey(x, kbuf)
399 /** An invalid page number.
400 * Mainly used to denote an empty tree.
402 #define P_INVALID (~(pgno_t)0)
404 /** Test if the flags \b f are set in a flag word \b w. */
405 #define F_ISSET(w, f) (((w) & (f)) == (f))
407 /** Used for offsets within a single page.
408 * Since memory pages are typically 4 or 8KB in size, 12-13 bits,
411 typedef uint16_t indx_t;
413 /** Default size of memory map.
414 * This is certainly too small for any actual applications. Apps should always set
415 * the size explicitly using #mdb_env_set_mapsize().
417 #define DEFAULT_MAPSIZE 1048576
419 /** @defgroup readers Reader Lock Table
420 * Readers don't acquire any locks for their data access. Instead, they
421 * simply record their transaction ID in the reader table. The reader
422 * mutex is needed just to find an empty slot in the reader table. The
423 * slot's address is saved in thread-specific data so that subsequent read
424 * transactions started by the same thread need no further locking to proceed.
426 * If #MDB_NOTLS is set, the slot address is not saved in thread-specific data.
428 * No reader table is used if the database is on a read-only filesystem.
430 * Since the database uses multi-version concurrency control, readers don't
431 * actually need any locking. This table is used to keep track of which
432 * readers are using data from which old transactions, so that we'll know
433 * when a particular old transaction is no longer in use. Old transactions
434 * that have discarded any data pages can then have those pages reclaimed
435 * for use by a later write transaction.
437 * The lock table is constructed such that reader slots are aligned with the
438 * processor's cache line size. Any slot is only ever used by one thread.
439 * This alignment guarantees that there will be no contention or cache
440 * thrashing as threads update their own slot info, and also eliminates
441 * any need for locking when accessing a slot.
443 * A writer thread will scan every slot in the table to determine the oldest
444 * outstanding reader transaction. Any freed pages older than this will be
445 * reclaimed by the writer. The writer doesn't use any locks when scanning
446 * this table. This means that there's no guarantee that the writer will
447 * see the most up-to-date reader info, but that's not required for correct
448 * operation - all we need is to know the upper bound on the oldest reader,
449 * we don't care at all about the newest reader. So the only consequence of
450 * reading stale information here is that old pages might hang around a
451 * while longer before being reclaimed. That's actually good anyway, because
452 * the longer we delay reclaiming old pages, the more likely it is that a
453 * string of contiguous pages can be found after coalescing old pages from
454 * many old transactions together.
457 /** Number of slots in the reader table.
458 * This value was chosen somewhat arbitrarily. 126 readers plus a
459 * couple mutexes fit exactly into 8KB on my development machine.
460 * Applications should set the table size using #mdb_env_set_maxreaders().
462 #define DEFAULT_READERS 126
464 /** The size of a CPU cache line in bytes. We want our lock structures
465 * aligned to this size to avoid false cache line sharing in the
467 * This value works for most CPUs. For Itanium this should be 128.
473 /** The information we store in a single slot of the reader table.
474 * In addition to a transaction ID, we also record the process and
475 * thread ID that owns a slot, so that we can detect stale information,
476 * e.g. threads or processes that went away without cleaning up.
477 * @note We currently don't check for stale records. We simply re-init
478 * the table when we know that we're the only process opening the
481 typedef struct MDB_rxbody {
482 /** Current Transaction ID when this transaction began, or (txnid_t)-1.
483 * Multiple readers that start at the same time will probably have the
484 * same ID here. Again, it's not important to exclude them from
485 * anything; all we need to know is which version of the DB they
486 * started from so we can avoid overwriting any data used in that
487 * particular version.
490 /** The process ID of the process owning this reader txn. */
492 /** The thread ID of the thread owning this txn. */
496 /** The actual reader record, with cacheline padding. */
497 typedef struct MDB_reader {
500 /** shorthand for mrb_txnid */
501 #define mr_txnid mru.mrx.mrb_txnid
502 #define mr_pid mru.mrx.mrb_pid
503 #define mr_tid mru.mrx.mrb_tid
504 /** cache line alignment */
505 char pad[(sizeof(MDB_rxbody)+CACHELINE-1) & ~(CACHELINE-1)];
509 /** The header for the reader table.
510 * The table resides in a memory-mapped file. (This is a different file
511 * than is used for the main database.)
513 * For POSIX the actual mutexes reside in the shared memory of this
514 * mapped file. On Windows, mutexes are named objects allocated by the
515 * kernel; we store the mutex names in this mapped file so that other
516 * processes can grab them. This same approach is also used on
517 * MacOSX/Darwin (using named semaphores) since MacOSX doesn't support
518 * process-shared POSIX mutexes. For these cases where a named object
519 * is used, the object name is derived from a 64 bit FNV hash of the
520 * environment pathname. As such, naming collisions are extremely
521 * unlikely. If a collision occurs, the results are unpredictable.
523 typedef struct MDB_txbody {
524 /** Stamp identifying this as an MDB file. It must be set
527 /** Format of this lock file. Must be set to #MDB_LOCK_FORMAT. */
529 #if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
530 char mtb_rmname[MNAME_LEN];
532 /** Mutex protecting access to this table.
533 * This is the reader lock that #LOCK_MUTEX_R acquires.
535 pthread_mutex_t mtb_mutex;
537 /** The ID of the last transaction committed to the database.
538 * This is recorded here only for convenience; the value can always
539 * be determined by reading the main database meta pages.
542 /** The number of slots that have been used in the reader table.
543 * This always records the maximum count, it is not decremented
544 * when readers release their slots.
546 unsigned mtb_numreaders;
549 /** The actual reader table definition. */
550 typedef struct MDB_txninfo {
553 #define mti_magic mt1.mtb.mtb_magic
554 #define mti_format mt1.mtb.mtb_format
555 #define mti_mutex mt1.mtb.mtb_mutex
556 #define mti_rmname mt1.mtb.mtb_rmname
557 #define mti_txnid mt1.mtb.mtb_txnid
558 #define mti_numreaders mt1.mtb.mtb_numreaders
559 char pad[(sizeof(MDB_txbody)+CACHELINE-1) & ~(CACHELINE-1)];
562 #if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
563 char mt2_wmname[MNAME_LEN];
564 #define mti_wmname mt2.mt2_wmname
566 pthread_mutex_t mt2_wmutex;
567 #define mti_wmutex mt2.mt2_wmutex
569 char pad[(MNAME_LEN+CACHELINE-1) & ~(CACHELINE-1)];
571 MDB_reader mti_readers[1];
574 /** Lockfile format signature: version, features and field layout */
575 #define MDB_LOCK_FORMAT \
577 ((MDB_LOCK_VERSION) \
578 /* Flags which describe functionality */ \
579 + (((MDB_PIDLOCK) != 0) << 16)))
582 /** Common header for all page types.
583 * Overflow records occupy a number of contiguous pages with no
584 * headers on any page after the first.
586 typedef struct MDB_page {
587 #define mp_pgno mp_p.p_pgno
588 #define mp_next mp_p.p_next
590 pgno_t p_pgno; /**< page number */
591 void * p_next; /**< for in-memory list of freed structs */
594 /** @defgroup mdb_page Page Flags
596 * Flags for the page headers.
599 #define P_BRANCH 0x01 /**< branch page */
600 #define P_LEAF 0x02 /**< leaf page */
601 #define P_OVERFLOW 0x04 /**< overflow page */
602 #define P_META 0x08 /**< meta page */
603 #define P_DIRTY 0x10 /**< dirty page */
604 #define P_LEAF2 0x20 /**< for #MDB_DUPFIXED records */
605 #define P_SUBP 0x40 /**< for #MDB_DUPSORT sub-pages */
606 #define P_KEEP 0x8000 /**< leave this page alone during spill */
608 uint16_t mp_flags; /**< @ref mdb_page */
609 #define mp_lower mp_pb.pb.pb_lower
610 #define mp_upper mp_pb.pb.pb_upper
611 #define mp_pages mp_pb.pb_pages
614 indx_t pb_lower; /**< lower bound of free space */
615 indx_t pb_upper; /**< upper bound of free space */
617 uint32_t pb_pages; /**< number of overflow pages */
619 indx_t mp_ptrs[1]; /**< dynamic size */
622 /** Size of the page header, excluding dynamic data at the end */
623 #define PAGEHDRSZ ((unsigned) offsetof(MDB_page, mp_ptrs))
625 /** Address of first usable data byte in a page, after the header */
626 #define METADATA(p) ((void *)((char *)(p) + PAGEHDRSZ))
628 /** Number of nodes on a page */
629 #define NUMKEYS(p) (((p)->mp_lower - PAGEHDRSZ) >> 1)
631 /** The amount of space remaining in the page */
632 #define SIZELEFT(p) (indx_t)((p)->mp_upper - (p)->mp_lower)
634 /** The percentage of space used in the page, in tenths of a percent. */
635 #define PAGEFILL(env, p) (1000L * ((env)->me_psize - PAGEHDRSZ - SIZELEFT(p)) / \
636 ((env)->me_psize - PAGEHDRSZ))
637 /** The minimum page fill factor, in tenths of a percent.
638 * Pages emptier than this are candidates for merging.
640 #define FILL_THRESHOLD 250
642 /** Test if a page is a leaf page */
643 #define IS_LEAF(p) F_ISSET((p)->mp_flags, P_LEAF)
644 /** Test if a page is a LEAF2 page */
645 #define IS_LEAF2(p) F_ISSET((p)->mp_flags, P_LEAF2)
646 /** Test if a page is a branch page */
647 #define IS_BRANCH(p) F_ISSET((p)->mp_flags, P_BRANCH)
648 /** Test if a page is an overflow page */
649 #define IS_OVERFLOW(p) F_ISSET((p)->mp_flags, P_OVERFLOW)
650 /** Test if a page is a sub page */
651 #define IS_SUBP(p) F_ISSET((p)->mp_flags, P_SUBP)
653 /** The number of overflow pages needed to store the given size. */
654 #define OVPAGES(size, psize) ((PAGEHDRSZ-1 + (size)) / (psize) + 1)
656 /** Header for a single key/data pair within a page.
657 * We guarantee 2-byte alignment for nodes.
659 typedef struct MDB_node {
660 /** lo and hi are used for data size on leaf nodes and for
661 * child pgno on branch nodes. On 64 bit platforms, flags
662 * is also used for pgno. (Branch nodes have no flags).
663 * They are in host byte order in case that lets some
664 * accesses be optimized into a 32-bit word access.
666 #define mn_lo mn_offset[BYTE_ORDER!=LITTLE_ENDIAN]
667 #define mn_hi mn_offset[BYTE_ORDER==LITTLE_ENDIAN] /**< part of dsize or pgno */
668 unsigned short mn_offset[2]; /**< storage for #mn_lo and #mn_hi */
669 /** @defgroup mdb_node Node Flags
671 * Flags for node headers.
674 #define F_BIGDATA 0x01 /**< data put on overflow page */
675 #define F_SUBDATA 0x02 /**< data is a sub-database */
676 #define F_DUPDATA 0x04 /**< data has duplicates */
678 /** valid flags for #mdb_node_add() */
679 #define NODE_ADD_FLAGS (F_DUPDATA|F_SUBDATA|MDB_RESERVE|MDB_APPEND)
682 unsigned short mn_flags; /**< @ref mdb_node */
683 unsigned short mn_ksize; /**< key size */
684 char mn_data[1]; /**< key and data are appended here */
687 /** Size of the node header, excluding dynamic data at the end */
688 #define NODESIZE offsetof(MDB_node, mn_data)
690 /** Bit position of top word in page number, for shifting mn_flags */
691 #define PGNO_TOPWORD ((pgno_t)-1 > 0xffffffffu ? 32 : 0)
693 /** Size of a node in a branch page with a given key.
694 * This is just the node header plus the key, there is no data.
696 #define INDXSIZE(k) (NODESIZE + ((k) == NULL ? 0 : (k)->mv_size))
698 /** Size of a node in a leaf page with a given key and data.
699 * This is node header plus key plus data size.
701 #define LEAFSIZE(k, d) (NODESIZE + (k)->mv_size + (d)->mv_size)
703 /** Address of node \b i in page \b p */
704 #define NODEPTR(p, i) ((MDB_node *)((char *)(p) + (p)->mp_ptrs[i]))
706 /** Address of the key for the node */
707 #define NODEKEY(node) (void *)((node)->mn_data)
709 /** Address of the data for a node */
710 #define NODEDATA(node) (void *)((char *)(node)->mn_data + (node)->mn_ksize)
712 /** Get the page number pointed to by a branch node */
713 #define NODEPGNO(node) \
714 ((node)->mn_lo | ((pgno_t) (node)->mn_hi << 16) | \
715 (PGNO_TOPWORD ? ((pgno_t) (node)->mn_flags << PGNO_TOPWORD) : 0))
716 /** Set the page number in a branch node */
717 #define SETPGNO(node,pgno) do { \
718 (node)->mn_lo = (pgno) & 0xffff; (node)->mn_hi = (pgno) >> 16; \
719 if (PGNO_TOPWORD) (node)->mn_flags = (pgno) >> PGNO_TOPWORD; } while(0)
721 /** Get the size of the data in a leaf node */
722 #define NODEDSZ(node) ((node)->mn_lo | ((unsigned)(node)->mn_hi << 16))
723 /** Set the size of the data for a leaf node */
724 #define SETDSZ(node,size) do { \
725 (node)->mn_lo = (size) & 0xffff; (node)->mn_hi = (size) >> 16;} while(0)
726 /** The size of a key in a node */
727 #define NODEKSZ(node) ((node)->mn_ksize)
729 /** Copy a page number from src to dst */
731 #define COPY_PGNO(dst,src) dst = src
733 #if SIZE_MAX > 4294967295UL
734 #define COPY_PGNO(dst,src) do { \
735 unsigned short *s, *d; \
736 s = (unsigned short *)&(src); \
737 d = (unsigned short *)&(dst); \
744 #define COPY_PGNO(dst,src) do { \
745 unsigned short *s, *d; \
746 s = (unsigned short *)&(src); \
747 d = (unsigned short *)&(dst); \
753 /** The address of a key in a LEAF2 page.
754 * LEAF2 pages are used for #MDB_DUPFIXED sorted-duplicate sub-DBs.
755 * There are no node headers, keys are stored contiguously.
757 #define LEAF2KEY(p, i, ks) ((char *)(p) + PAGEHDRSZ + ((i)*(ks)))
759 /** Set the \b node's key into \b keyptr, if requested. */
760 #define MDB_GET_KEY(node, keyptr) { if ((keyptr) != NULL) { \
761 (keyptr)->mv_size = NODEKSZ(node); (keyptr)->mv_data = NODEKEY(node); } }
763 /** Set the \b node's key into \b key. */
764 #define MDB_GET_KEY2(node, key) { key.mv_size = NODEKSZ(node); key.mv_data = NODEKEY(node); }
766 /** Information about a single database in the environment. */
767 typedef struct MDB_db {
768 uint32_t md_pad; /**< also ksize for LEAF2 pages */
769 uint16_t md_flags; /**< @ref mdb_dbi_open */
770 uint16_t md_depth; /**< depth of this tree */
771 pgno_t md_branch_pages; /**< number of internal pages */
772 pgno_t md_leaf_pages; /**< number of leaf pages */
773 pgno_t md_overflow_pages; /**< number of overflow pages */
774 size_t md_entries; /**< number of data items */
775 pgno_t md_root; /**< the root page of this tree */
778 /** mdb_dbi_open flags */
779 #define MDB_VALID 0x8000 /**< DB handle is valid, for me_dbflags */
780 #define PERSISTENT_FLAGS (0xffff & ~(MDB_VALID))
781 #define VALID_FLAGS (MDB_REVERSEKEY|MDB_DUPSORT|MDB_INTEGERKEY|MDB_DUPFIXED|\
782 MDB_INTEGERDUP|MDB_REVERSEDUP|MDB_CREATE)
784 /** Handle for the DB used to track free pages. */
786 /** Handle for the default DB. */
789 /** Meta page content. */
790 typedef struct MDB_meta {
791 /** Stamp identifying this as an MDB file. It must be set
794 /** Version number of this lock file. Must be set to #MDB_DATA_VERSION. */
796 void *mm_address; /**< address for fixed mapping */
797 size_t mm_mapsize; /**< size of mmap region */
798 MDB_db mm_dbs[2]; /**< first is free space, 2nd is main db */
799 /** The size of pages used in this DB */
800 #define mm_psize mm_dbs[0].md_pad
801 /** Any persistent environment flags. @ref mdb_env */
802 #define mm_flags mm_dbs[0].md_flags
803 pgno_t mm_last_pg; /**< last used page in file */
804 txnid_t mm_txnid; /**< txnid that committed this page */
807 /** Buffer for a stack-allocated dirty page.
808 * The members define size and alignment, and silence type
809 * aliasing warnings. They are not used directly; that could
810 * mean incorrectly using several union members in parallel.
812 typedef union MDB_pagebuf {
813 char mb_raw[MDB_PAGESIZE];
816 char mm_pad[PAGEHDRSZ];
821 /** Auxiliary DB info.
822 * The information here is mostly static/read-only. There is
823 * only a single copy of this record in the environment.
825 typedef struct MDB_dbx {
826 MDB_val md_name; /**< name of the database */
827 MDB_cmp_func *md_cmp; /**< function for comparing keys */
828 MDB_cmp_func *md_dcmp; /**< function for comparing data items */
829 MDB_rel_func *md_rel; /**< user relocate function */
830 void *md_relctx; /**< user-provided context for md_rel */
833 /** A database transaction.
834 * Every operation requires a transaction handle.
837 MDB_txn *mt_parent; /**< parent of a nested txn */
838 MDB_txn *mt_child; /**< nested txn under this txn */
839 pgno_t mt_next_pgno; /**< next unallocated page */
840 /** The ID of this transaction. IDs are integers incrementing from 1.
841 * Only committed write transactions increment the ID. If a transaction
842 * aborts, the ID may be re-used by the next writer.
845 MDB_env *mt_env; /**< the DB environment */
846 /** The list of pages that became unused during this transaction.
849 /** The sorted list of dirty pages we temporarily wrote to disk
850 * because the dirty list was full. page numbers in here are
851 * shifted left by 1, deleted slots have the LSB set.
853 MDB_IDL mt_spill_pgs;
855 /** For write txns: Modified pages. Sorted when not MDB_WRITEMAP. */
857 /** For read txns: This thread/txn's reader table slot, or NULL. */
860 /** Array of records for each DB known in the environment. */
862 /** Array of MDB_db records for each known DB */
864 /** @defgroup mt_dbflag Transaction DB Flags
868 #define DB_DIRTY 0x01 /**< DB was written in this txn */
869 #define DB_STALE 0x02 /**< DB record is older than txnID */
870 #define DB_NEW 0x04 /**< DB handle opened in this txn */
871 #define DB_VALID 0x08 /**< DB handle is valid, see also #MDB_VALID */
873 /** In write txns, array of cursors for each DB */
874 MDB_cursor **mt_cursors;
875 /** Array of flags for each DB */
876 unsigned char *mt_dbflags;
877 /** Number of DB records in use. This number only ever increments;
878 * we don't decrement it when individual DB handles are closed.
882 /** @defgroup mdb_txn Transaction Flags
886 #define MDB_TXN_RDONLY 0x01 /**< read-only transaction */
887 #define MDB_TXN_ERROR 0x02 /**< an error has occurred */
888 #define MDB_TXN_DIRTY 0x04 /**< must write, even if dirty list is empty */
889 #define MDB_TXN_SPILLS 0x08 /**< txn or a parent has spilled pages */
891 unsigned int mt_flags; /**< @ref mdb_txn */
892 /** dirty_list maxsize - # of allocated pages allowed, including in parent txns */
893 unsigned int mt_dirty_room;
894 /** Tracks which of the two meta pages was used at the start
895 * of this transaction.
897 unsigned int mt_toggle;
900 /** Enough space for 2^32 nodes with minimum of 2 keys per node. I.e., plenty.
901 * At 4 keys per node, enough for 2^64 nodes, so there's probably no need to
902 * raise this on a 64 bit machine.
904 #define CURSOR_STACK 32
908 /** Cursors are used for all DB operations */
910 /** Next cursor on this DB in this txn */
912 /** Backup of the original cursor if this cursor is a shadow */
913 MDB_cursor *mc_backup;
914 /** Context used for databases with #MDB_DUPSORT, otherwise NULL */
915 struct MDB_xcursor *mc_xcursor;
916 /** The transaction that owns this cursor */
918 /** The database handle this cursor operates on */
920 /** The database record for this cursor */
922 /** The database auxiliary record for this cursor */
924 /** The @ref mt_dbflag for this database */
925 unsigned char *mc_dbflag;
926 unsigned short mc_snum; /**< number of pushed pages */
927 unsigned short mc_top; /**< index of top page, normally mc_snum-1 */
928 /** @defgroup mdb_cursor Cursor Flags
930 * Cursor state flags.
933 #define C_INITIALIZED 0x01 /**< cursor has been initialized and is valid */
934 #define C_EOF 0x02 /**< No more data */
935 #define C_SUB 0x04 /**< Cursor is a sub-cursor */
936 #define C_DEL 0x08 /**< last op was a cursor_del */
937 #define C_SPLITTING 0x20 /**< Cursor is in page_split */
938 #define C_UNTRACK 0x40 /**< Un-track cursor when closing */
940 unsigned int mc_flags; /**< @ref mdb_cursor */
941 MDB_page *mc_pg[CURSOR_STACK]; /**< stack of pushed pages */
942 indx_t mc_ki[CURSOR_STACK]; /**< stack of page indices */
945 /** Context for sorted-dup records.
946 * We could have gone to a fully recursive design, with arbitrarily
947 * deep nesting of sub-databases. But for now we only handle these
948 * levels - main DB, optional sub-DB, sorted-duplicate DB.
950 typedef struct MDB_xcursor {
951 /** A sub-cursor for traversing the Dup DB */
952 MDB_cursor mx_cursor;
953 /** The database record for this Dup DB */
955 /** The auxiliary DB record for this Dup DB */
957 /** The @ref mt_dbflag for this Dup DB */
958 unsigned char mx_dbflag;
961 /** State of FreeDB old pages, stored in the MDB_env */
962 typedef struct MDB_pgstate {
963 pgno_t *mf_pghead; /**< Reclaimed freeDB pages, or NULL before use */
964 txnid_t mf_pglast; /**< ID of last used record, or 0 if !mf_pghead */
967 /** The database environment. */
969 HANDLE me_fd; /**< The main data file */
970 HANDLE me_lfd; /**< The lock file */
971 HANDLE me_mfd; /**< just for writing the meta pages */
972 /** Failed to update the meta page. Probably an I/O error. */
973 #define MDB_FATAL_ERROR 0x80000000U
974 /** Some fields are initialized. */
975 #define MDB_ENV_ACTIVE 0x20000000U
976 /** me_txkey is set */
977 #define MDB_ENV_TXKEY 0x10000000U
978 /** Have liveness lock in reader table */
979 #define MDB_LIVE_READER 0x08000000U
980 uint32_t me_flags; /**< @ref mdb_env */
981 unsigned int me_psize; /**< size of a page, from #GET_PAGESIZE */
982 unsigned int me_maxreaders; /**< size of the reader table */
983 unsigned int me_numreaders; /**< max numreaders set by this env */
984 MDB_dbi me_numdbs; /**< number of DBs opened */
985 MDB_dbi me_maxdbs; /**< size of the DB table */
986 pid_t me_pid; /**< process ID of this env */
987 char *me_path; /**< path to the DB files */
988 char *me_map; /**< the memory map of the data file */
989 MDB_txninfo *me_txns; /**< the memory map of the lock file or NULL */
990 MDB_meta *me_metas[2]; /**< pointers to the two meta pages */
991 MDB_txn *me_txn; /**< current write transaction */
992 size_t me_mapsize; /**< size of the data memory map */
993 off_t me_size; /**< current file size */
994 pgno_t me_maxpg; /**< me_mapsize / me_psize */
995 MDB_dbx *me_dbxs; /**< array of static DB info */
996 uint16_t *me_dbflags; /**< array of flags from MDB_db.md_flags */
997 pthread_key_t me_txkey; /**< thread-key for readers */
998 MDB_pgstate me_pgstate; /**< state of old pages from freeDB */
999 # define me_pglast me_pgstate.mf_pglast
1000 # define me_pghead me_pgstate.mf_pghead
1001 MDB_page *me_dpages; /**< list of malloc'd blocks for re-use */
1002 /** IDL of pages that became unused in a write txn */
1003 MDB_IDL me_free_pgs;
1004 /** ID2L of pages written during a write txn. Length MDB_IDL_UM_SIZE. */
1005 MDB_ID2L me_dirty_list;
1006 /** Max number of freelist items that can fit in a single overflow page */
1008 /** Max size of a node on a page */
1009 unsigned int me_nodemax;
1011 int me_pidquery; /**< Used in OpenProcess */
1012 HANDLE me_rmutex; /* Windows mutexes don't reside in shared mem */
1014 #elif defined(MDB_USE_POSIX_SEM)
1015 sem_t *me_rmutex; /* Shared mutexes are not supported */
1020 /** Nested transaction */
1021 typedef struct MDB_ntxn {
1022 MDB_txn mnt_txn; /* the transaction */
1023 MDB_pgstate mnt_pgstate; /* parent transaction's saved freestate */
1026 /** max number of pages to commit in one writev() call */
1027 #define MDB_COMMIT_PAGES 64
1028 #if defined(IOV_MAX) && IOV_MAX < MDB_COMMIT_PAGES
1029 #undef MDB_COMMIT_PAGES
1030 #define MDB_COMMIT_PAGES IOV_MAX
1033 /* max bytes to write in one call */
1034 #define MAX_WRITE (0x80000000U >> (sizeof(ssize_t) == 4))
1036 static int mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp);
1037 static int mdb_page_new(MDB_cursor *mc, uint32_t flags, int num, MDB_page **mp);
1038 static int mdb_page_touch(MDB_cursor *mc);
1040 static int mdb_page_get(MDB_txn *txn, pgno_t pgno, MDB_page **mp, int *lvl);
1041 static int mdb_page_search_root(MDB_cursor *mc,
1042 MDB_val *key, int modify);
1043 #define MDB_PS_MODIFY 1
1044 #define MDB_PS_ROOTONLY 2
1045 static int mdb_page_search(MDB_cursor *mc,
1046 MDB_val *key, int flags);
1047 static int mdb_page_merge(MDB_cursor *csrc, MDB_cursor *cdst);
1049 #define MDB_SPLIT_REPLACE MDB_APPENDDUP /**< newkey is not new */
1050 static int mdb_page_split(MDB_cursor *mc, MDB_val *newkey, MDB_val *newdata,
1051 pgno_t newpgno, unsigned int nflags);
1053 static int mdb_env_read_header(MDB_env *env, MDB_meta *meta);
1054 static int mdb_env_pick_meta(const MDB_env *env);
1055 static int mdb_env_write_meta(MDB_txn *txn);
1056 #if !(defined(_WIN32) || defined(MDB_USE_POSIX_SEM)) /* Drop unused excl arg */
1057 # define mdb_env_close0(env, excl) mdb_env_close1(env)
1059 static void mdb_env_close0(MDB_env *env, int excl);
1061 static MDB_node *mdb_node_search(MDB_cursor *mc, MDB_val *key, int *exactp);
1062 static int mdb_node_add(MDB_cursor *mc, indx_t indx,
1063 MDB_val *key, MDB_val *data, pgno_t pgno, unsigned int flags);
1064 static void mdb_node_del(MDB_page *mp, indx_t indx, int ksize);
1065 static void mdb_node_shrink(MDB_page *mp, indx_t indx);
1066 static int mdb_node_move(MDB_cursor *csrc, MDB_cursor *cdst);
1067 static int mdb_node_read(MDB_txn *txn, MDB_node *leaf, MDB_val *data);
1068 static size_t mdb_leaf_size(MDB_env *env, MDB_val *key, MDB_val *data);
1069 static size_t mdb_branch_size(MDB_env *env, MDB_val *key);
1071 static int mdb_rebalance(MDB_cursor *mc);
1072 static int mdb_update_key(MDB_cursor *mc, MDB_val *key);
1074 static void mdb_cursor_pop(MDB_cursor *mc);
1075 static int mdb_cursor_push(MDB_cursor *mc, MDB_page *mp);
1077 static int mdb_cursor_del0(MDB_cursor *mc, MDB_node *leaf);
1078 static int mdb_cursor_sibling(MDB_cursor *mc, int move_right);
1079 static int mdb_cursor_next(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op);
1080 static int mdb_cursor_prev(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op);
1081 static int mdb_cursor_set(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op,
1083 static int mdb_cursor_first(MDB_cursor *mc, MDB_val *key, MDB_val *data);
1084 static int mdb_cursor_last(MDB_cursor *mc, MDB_val *key, MDB_val *data);
1086 static void mdb_cursor_init(MDB_cursor *mc, MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx);
1087 static void mdb_xcursor_init0(MDB_cursor *mc);
1088 static void mdb_xcursor_init1(MDB_cursor *mc, MDB_node *node);
1090 static int mdb_drop0(MDB_cursor *mc, int subs);
1091 static void mdb_default_cmp(MDB_txn *txn, MDB_dbi dbi);
1094 static MDB_cmp_func mdb_cmp_memn, mdb_cmp_memnr, mdb_cmp_int, mdb_cmp_cint, mdb_cmp_long;
1098 static SECURITY_DESCRIPTOR mdb_null_sd;
1099 static SECURITY_ATTRIBUTES mdb_all_sa;
1100 static int mdb_sec_inited;
1103 /** Return the library version info. */
1105 mdb_version(int *major, int *minor, int *patch)
1107 if (major) *major = MDB_VERSION_MAJOR;
1108 if (minor) *minor = MDB_VERSION_MINOR;
1109 if (patch) *patch = MDB_VERSION_PATCH;
1110 return MDB_VERSION_STRING;
1113 /** Table of descriptions for MDB @ref errors */
1114 static char *const mdb_errstr[] = {
1115 "MDB_KEYEXIST: Key/data pair already exists",
1116 "MDB_NOTFOUND: No matching key/data pair found",
1117 "MDB_PAGE_NOTFOUND: Requested page not found",
1118 "MDB_CORRUPTED: Located page was wrong type",
1119 "MDB_PANIC: Update of meta page failed",
1120 "MDB_VERSION_MISMATCH: Database environment version mismatch",
1121 "MDB_INVALID: File is not an MDB file",
1122 "MDB_MAP_FULL: Environment mapsize limit reached",
1123 "MDB_DBS_FULL: Environment maxdbs limit reached",
1124 "MDB_READERS_FULL: Environment maxreaders limit reached",
1125 "MDB_TLS_FULL: Thread-local storage keys full - too many environments open",
1126 "MDB_TXN_FULL: Transaction has too many dirty pages - transaction too big",
1127 "MDB_CURSOR_FULL: Internal error - cursor stack limit reached",
1128 "MDB_PAGE_FULL: Internal error - page has no more space",
1129 "MDB_MAP_RESIZED: Database contents grew beyond environment mapsize",
1130 "MDB_INCOMPATIBLE: Operation and DB incompatible, or DB flags changed",
1131 "MDB_BAD_RSLOT: Invalid reuse of reader locktable slot",
1132 "MDB_BAD_TXN: Transaction cannot recover - it must be aborted",
1133 "MDB_BAD_VALSIZE: Too big key/data, key is empty, or wrong DUPFIXED size",
1137 mdb_strerror(int err)
1141 return ("Successful return: 0");
1143 if (err >= MDB_KEYEXIST && err <= MDB_LAST_ERRCODE) {
1144 i = err - MDB_KEYEXIST;
1145 return mdb_errstr[i];
1148 return strerror(err);
1152 /** Display a key in hexadecimal and return the address of the result.
1153 * @param[in] key the key to display
1154 * @param[in] buf the buffer to write into. Should always be #DKBUF.
1155 * @return The key in hexadecimal form.
1158 mdb_dkey(MDB_val *key, char *buf)
1161 unsigned char *c = key->mv_data;
1167 if (key->mv_size > MDB_MAXKEYSIZE)
1168 return "MDB_MAXKEYSIZE";
1169 /* may want to make this a dynamic check: if the key is mostly
1170 * printable characters, print it as-is instead of converting to hex.
1174 for (i=0; i<key->mv_size; i++)
1175 ptr += sprintf(ptr, "%02x", *c++);
1177 sprintf(buf, "%.*s", key->mv_size, key->mv_data);
1182 /** Display all the keys in the page. */
1184 mdb_page_list(MDB_page *mp)
1187 unsigned int i, nkeys, nsize;
1191 nkeys = NUMKEYS(mp);
1192 fprintf(stderr, "Page %"Z"u numkeys %d\n", mp->mp_pgno, nkeys);
1193 for (i=0; i<nkeys; i++) {
1194 node = NODEPTR(mp, i);
1195 key.mv_size = node->mn_ksize;
1196 key.mv_data = node->mn_data;
1197 nsize = NODESIZE + NODEKSZ(node) + sizeof(indx_t);
1198 if (IS_BRANCH(mp)) {
1199 fprintf(stderr, "key %d: page %"Z"u, %s\n", i, NODEPGNO(node),
1202 if (F_ISSET(node->mn_flags, F_BIGDATA))
1203 nsize += sizeof(pgno_t);
1205 nsize += NODEDSZ(node);
1206 fprintf(stderr, "key %d: nsize %d, %s\n", i, nsize, DKEY(&key));
1212 mdb_cursor_chk(MDB_cursor *mc)
1218 if (!mc->mc_snum && !(mc->mc_flags & C_INITIALIZED)) return;
1219 for (i=0; i<mc->mc_top; i++) {
1221 node = NODEPTR(mp, mc->mc_ki[i]);
1222 if (NODEPGNO(node) != mc->mc_pg[i+1]->mp_pgno)
1225 if (mc->mc_ki[i] >= NUMKEYS(mc->mc_pg[i]))
1231 /** Count all the pages in each DB and in the freelist
1232 * and make sure it matches the actual number of pages
1235 static void mdb_audit(MDB_txn *txn)
1239 MDB_ID freecount, count;
1244 mdb_cursor_init(&mc, txn, FREE_DBI, NULL);
1245 while ((rc = mdb_cursor_get(&mc, &key, &data, MDB_NEXT)) == 0)
1246 freecount += *(MDB_ID *)data.mv_data;
1249 for (i = 0; i<txn->mt_numdbs; i++) {
1251 mdb_cursor_init(&mc, txn, i, &mx);
1252 if (txn->mt_dbs[i].md_root == P_INVALID)
1254 count += txn->mt_dbs[i].md_branch_pages +
1255 txn->mt_dbs[i].md_leaf_pages +
1256 txn->mt_dbs[i].md_overflow_pages;
1257 if (txn->mt_dbs[i].md_flags & MDB_DUPSORT) {
1258 mdb_page_search(&mc, NULL, 0);
1262 mp = mc.mc_pg[mc.mc_top];
1263 for (j=0; j<NUMKEYS(mp); j++) {
1264 MDB_node *leaf = NODEPTR(mp, j);
1265 if (leaf->mn_flags & F_SUBDATA) {
1267 memcpy(&db, NODEDATA(leaf), sizeof(db));
1268 count += db.md_branch_pages + db.md_leaf_pages +
1269 db.md_overflow_pages;
1273 while (mdb_cursor_sibling(&mc, 1) == 0);
1276 if (freecount + count + 2 /* metapages */ != txn->mt_next_pgno) {
1277 fprintf(stderr, "audit: %lu freecount: %lu count: %lu total: %lu next_pgno: %lu\n",
1278 txn->mt_txnid, freecount, count+2, freecount+count+2, txn->mt_next_pgno);
1284 mdb_cmp(MDB_txn *txn, MDB_dbi dbi, const MDB_val *a, const MDB_val *b)
1286 return txn->mt_dbxs[dbi].md_cmp(a, b);
1290 mdb_dcmp(MDB_txn *txn, MDB_dbi dbi, const MDB_val *a, const MDB_val *b)
1292 return txn->mt_dbxs[dbi].md_dcmp(a, b);
1295 /** Allocate memory for a page.
1296 * Re-use old malloc'd pages first for singletons, otherwise just malloc.
1299 mdb_page_malloc(MDB_txn *txn, unsigned num)
1301 MDB_env *env = txn->mt_env;
1302 MDB_page *ret = env->me_dpages;
1303 size_t sz = env->me_psize;
1306 VGMEMP_ALLOC(env, ret, sz);
1307 VGMEMP_DEFINED(ret, sizeof(ret->mp_next));
1308 env->me_dpages = ret->mp_next;
1314 if ((ret = malloc(sz)) != NULL) {
1315 VGMEMP_ALLOC(env, ret, sz);
1320 /** Free a single page.
1321 * Saves single pages to a list, for future reuse.
1322 * (This is not used for multi-page overflow pages.)
1325 mdb_page_free(MDB_env *env, MDB_page *mp)
1327 mp->mp_next = env->me_dpages;
1328 VGMEMP_FREE(env, mp);
1329 env->me_dpages = mp;
1332 /* Free a dirty page */
1334 mdb_dpage_free(MDB_env *env, MDB_page *dp)
1336 if (!IS_OVERFLOW(dp) || dp->mp_pages == 1) {
1337 mdb_page_free(env, dp);
1339 /* large pages just get freed directly */
1340 VGMEMP_FREE(env, dp);
1345 /** Return all dirty pages to dpage list */
1347 mdb_dlist_free(MDB_txn *txn)
1349 MDB_env *env = txn->mt_env;
1350 MDB_ID2L dl = txn->mt_u.dirty_list;
1351 unsigned i, n = dl[0].mid;
1353 for (i = 1; i <= n; i++) {
1354 mdb_dpage_free(env, dl[i].mptr);
1359 /* Set or clear P_KEEP in dirty, non-overflow, non-sub pages watched by txn.
1360 * @param[in] mc A cursor handle for the current operation.
1361 * @param[in] pflags Flags of the pages to update:
1362 * P_DIRTY to set P_KEEP, P_DIRTY|P_KEEP to clear it.
1363 * @param[in] all No shortcuts. Needed except after a full #mdb_page_flush().
1364 * @return 0 on success, non-zero on failure.
1367 mdb_pages_xkeep(MDB_cursor *mc, unsigned pflags, int all)
1369 MDB_txn *txn = mc->mc_txn;
1374 int rc = MDB_SUCCESS, level;
1376 /* Mark pages seen by cursors */
1377 if (mc->mc_flags & C_UNTRACK)
1378 mc = NULL; /* will find mc in mt_cursors */
1379 for (i = txn->mt_numdbs;; mc = txn->mt_cursors[--i]) {
1380 for (; mc; mc=mc->mc_next) {
1381 for (m3 = mc; m3->mc_flags & C_INITIALIZED; m3 = &mx->mx_cursor) {
1382 for (j=0; j<m3->mc_snum; j++)
1383 if ((m3->mc_pg[j]->mp_flags & (P_SUBP|P_DIRTY|P_KEEP))
1385 m3->mc_pg[j]->mp_flags ^= P_KEEP;
1386 mx = m3->mc_xcursor;
1396 /* Mark dirty root pages */
1397 for (i=0; i<txn->mt_numdbs; i++) {
1398 if (txn->mt_dbflags[i] & DB_DIRTY) {
1399 pgno_t pgno = txn->mt_dbs[i].md_root;
1400 if (pgno == P_INVALID)
1402 if ((rc = mdb_page_get(txn, pgno, &dp, &level)) != MDB_SUCCESS)
1404 if ((dp->mp_flags & (P_DIRTY|P_KEEP)) == pflags && level <= 1)
1405 dp->mp_flags ^= P_KEEP;
1413 static int mdb_page_flush(MDB_txn *txn, int keep);
1415 /** Spill pages from the dirty list back to disk.
1416 * This is intended to prevent running into #MDB_TXN_FULL situations,
1417 * but note that they may still occur in a few cases:
1418 * 1) pages in #MDB_DUPSORT sub-DBs are never spilled, so if there
1419 * are too many of these dirtied in one txn, the txn may still get
1421 * 2) child txns may run out of space if their parents dirtied a
1422 * lot of pages and never spilled them. TODO: we probably should do
1423 * a preemptive spill during #mdb_txn_begin() of a child txn, if
1424 * the parent's dirty_room is below a given threshold.
1425 * 3) our estimate of the txn size could be too small. At the
1426 * moment this seems unlikely.
1428 * Otherwise, if not using nested txns, it is expected that apps will
1429 * not run into #MDB_TXN_FULL any more. The pages are flushed to disk
1430 * the same way as for a txn commit, e.g. their P_DIRTY flag is cleared.
1431 * If the txn never references them again, they can be left alone.
1432 * If the txn only reads them, they can be used without any fuss.
1433 * If the txn writes them again, they can be dirtied immediately without
1434 * going thru all of the work of #mdb_page_touch(). Such references are
1435 * handled by #mdb_page_unspill().
1437 * Also note, we never spill DB root pages, nor pages of active cursors,
1438 * because we'll need these back again soon anyway. And in nested txns,
1439 * we can't spill a page in a child txn if it was already spilled in a
1440 * parent txn. That would alter the parent txns' data even though
1441 * the child hasn't committed yet, and we'd have no way to undo it if
1442 * the child aborted.
1444 * @param[in] m0 cursor A cursor handle identifying the transaction and
1445 * database for which we are checking space.
1446 * @param[in] key For a put operation, the key being stored.
1447 * @param[in] data For a put operation, the data being stored.
1448 * @return 0 on success, non-zero on failure.
1451 mdb_page_spill(MDB_cursor *m0, MDB_val *key, MDB_val *data)
1453 MDB_txn *txn = m0->mc_txn;
1455 MDB_ID2L dl = txn->mt_u.dirty_list;
1456 unsigned int i, j, need;
1459 if (m0->mc_flags & C_SUB)
1462 /* Estimate how much space this op will take */
1463 i = m0->mc_db->md_depth;
1464 /* Named DBs also dirty the main DB */
1465 if (m0->mc_dbi > MAIN_DBI)
1466 i += txn->mt_dbs[MAIN_DBI].md_depth;
1467 /* For puts, roughly factor in the key+data size */
1469 i += (LEAFSIZE(key, data) + txn->mt_env->me_psize) / txn->mt_env->me_psize;
1470 i += i; /* double it for good measure */
1473 if (txn->mt_dirty_room > i)
1476 if (!txn->mt_spill_pgs) {
1477 txn->mt_spill_pgs = mdb_midl_alloc(MDB_IDL_UM_MAX);
1478 if (!txn->mt_spill_pgs)
1481 /* purge deleted slots */
1482 MDB_IDL sl = txn->mt_spill_pgs;
1483 unsigned int num = sl[0];
1485 for (i=1; i<=num; i++) {
1492 /* Preserve pages which may soon be dirtied again */
1493 if ((rc = mdb_pages_xkeep(m0, P_DIRTY, 1)) != MDB_SUCCESS)
1496 /* Less aggressive spill - we originally spilled the entire dirty list,
1497 * with a few exceptions for cursor pages and DB root pages. But this
1498 * turns out to be a lot of wasted effort because in a large txn many
1499 * of those pages will need to be used again. So now we spill only 1/8th
1500 * of the dirty pages. Testing revealed this to be a good tradeoff,
1501 * better than 1/2, 1/4, or 1/10.
1503 if (need < MDB_IDL_UM_MAX / 8)
1504 need = MDB_IDL_UM_MAX / 8;
1506 /* Save the page IDs of all the pages we're flushing */
1507 /* flush from the tail forward, this saves a lot of shifting later on. */
1508 for (i=dl[0].mid; i && need; i--) {
1509 MDB_ID pn = dl[i].mid << 1;
1511 if (dp->mp_flags & P_KEEP)
1513 /* Can't spill twice, make sure it's not already in a parent's
1516 if (txn->mt_parent) {
1518 for (tx2 = txn->mt_parent; tx2; tx2 = tx2->mt_parent) {
1519 if (tx2->mt_spill_pgs) {
1520 j = mdb_midl_search(tx2->mt_spill_pgs, pn);
1521 if (j <= tx2->mt_spill_pgs[0] && tx2->mt_spill_pgs[j] == pn) {
1522 dp->mp_flags |= P_KEEP;
1530 if ((rc = mdb_midl_append(&txn->mt_spill_pgs, pn)))
1534 mdb_midl_sort(txn->mt_spill_pgs);
1536 /* Flush the spilled part of dirty list */
1537 if ((rc = mdb_page_flush(txn, i)) != MDB_SUCCESS)
1540 /* Reset any dirty pages we kept that page_flush didn't see */
1541 rc = mdb_pages_xkeep(m0, P_DIRTY|P_KEEP, i);
1545 if (txn->mt_parent) {
1546 txn->mt_dirty_room = txn->mt_parent->mt_dirty_room - dl[0].mid;
1547 /* dirty pages that are dirty in an ancestor don't
1548 * count against this txn's dirty_room.
1550 for (i=1; i<=dl[0].mid; i++) {
1551 pgno_t pgno = dl[i].mid;
1553 for (tx2 = txn->mt_parent; tx2; tx2 = tx2->mt_parent) {
1554 j = mdb_mid2l_search(tx2->mt_u.dirty_list, pgno);
1555 if (j <= tx2->mt_u.dirty_list[0].mid &&
1556 tx2->mt_u.dirty_list[j].mid == pgno) {
1557 txn->mt_dirty_room++;
1563 txn->mt_dirty_room = MDB_IDL_UM_MAX - dl[0].mid;
1565 txn->mt_flags |= MDB_TXN_SPILLS;
1567 txn->mt_flags |= MDB_TXN_ERROR;
1572 /** Find oldest txnid still referenced. Expects txn->mt_txnid > 0. */
1574 mdb_find_oldest(MDB_txn *txn)
1577 txnid_t mr, oldest = txn->mt_txnid - 1;
1578 MDB_reader *r = txn->mt_env->me_txns->mti_readers;
1579 for (i = txn->mt_env->me_txns->mti_numreaders; --i >= 0; ) {
1589 /** Add a page to the txn's dirty list */
1591 mdb_page_dirty(MDB_txn *txn, MDB_page *mp)
1594 int (*insert)(MDB_ID2L, MDB_ID2 *);
1596 if (txn->mt_env->me_flags & MDB_WRITEMAP) {
1597 insert = mdb_mid2l_append;
1599 insert = mdb_mid2l_insert;
1601 mid.mid = mp->mp_pgno;
1603 insert(txn->mt_u.dirty_list, &mid);
1604 txn->mt_dirty_room--;
1607 /** Allocate page numbers and memory for writing. Maintain me_pglast,
1608 * me_pghead and mt_next_pgno.
1610 * If there are free pages available from older transactions, they
1611 * are re-used first. Otherwise allocate a new page at mt_next_pgno.
1612 * Do not modify the freedB, just merge freeDB records into me_pghead[]
1613 * and move me_pglast to say which records were consumed. Only this
1614 * function can create me_pghead and move me_pglast/mt_next_pgno.
1615 * @param[in] mc cursor A cursor handle identifying the transaction and
1616 * database for which we are allocating.
1617 * @param[in] num the number of pages to allocate.
1618 * @param[out] mp Address of the allocated page(s). Requests for multiple pages
1619 * will always be satisfied by a single contiguous chunk of memory.
1620 * @return 0 on success, non-zero on failure.
1623 mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp)
1625 #ifdef MDB_PARANOID /* Seems like we can ignore this now */
1626 /* Get at most <Max_retries> more freeDB records once me_pghead
1627 * has enough pages. If not enough, use new pages from the map.
1628 * If <Paranoid> and mc is updating the freeDB, only get new
1629 * records if me_pghead is empty. Then the freelist cannot play
1630 * catch-up with itself by growing while trying to save it.
1632 enum { Paranoid = 1, Max_retries = 500 };
1634 enum { Paranoid = 0, Max_retries = INT_MAX /*infinite*/ };
1636 int rc, n2 = num-1, retry = Max_retries;
1637 MDB_txn *txn = mc->mc_txn;
1638 MDB_env *env = txn->mt_env;
1639 pgno_t pgno, *mop = env->me_pghead;
1640 unsigned i, j, k, mop_len = mop ? mop[0] : 0;
1642 txnid_t oldest = 0, last;
1648 /* If our dirty list is already full, we can't do anything */
1649 if (txn->mt_dirty_room == 0)
1650 return MDB_TXN_FULL;
1652 for (op = MDB_FIRST;; op = MDB_NEXT) {
1655 pgno_t *idl, old_id, new_id;
1657 /* Seek a big enough contiguous page range. Prefer
1658 * pages at the tail, just truncating the list.
1660 if (mop_len >= (unsigned)num) {
1664 if (mop[i-n2] == pgno+n2)
1666 } while (--i >= (unsigned)num);
1667 if (Max_retries < INT_MAX && --retry < 0)
1671 if (op == MDB_FIRST) { /* 1st iteration */
1672 /* Prepare to fetch more and coalesce */
1673 oldest = mdb_find_oldest(txn);
1674 last = env->me_pglast;
1675 mdb_cursor_init(&m2, txn, FREE_DBI, NULL);
1678 key.mv_data = &last; /* will look up last+1 */
1679 key.mv_size = sizeof(last);
1681 if (Paranoid && mc->mc_dbi == FREE_DBI)
1684 if (Paranoid && retry < 0 && mop_len)
1688 /* Do not fetch more if the record will be too recent */
1691 rc = mdb_cursor_get(&m2, &key, NULL, op);
1693 if (rc == MDB_NOTFOUND)
1697 last = *(txnid_t*)key.mv_data;
1700 np = m2.mc_pg[m2.mc_top];
1701 leaf = NODEPTR(np, m2.mc_ki[m2.mc_top]);
1702 if ((rc = mdb_node_read(txn, leaf, &data)) != MDB_SUCCESS)
1705 idl = (MDB_ID *) data.mv_data;
1708 if (!(env->me_pghead = mop = mdb_midl_alloc(i)))
1711 if ((rc = mdb_midl_need(&env->me_pghead, i)) != 0)
1713 mop = env->me_pghead;
1715 env->me_pglast = last;
1717 DPRINTF(("IDL read txn %"Z"u root %"Z"u num %u",
1718 last, txn->mt_dbs[FREE_DBI].md_root, i));
1720 DPRINTF(("IDL %"Z"u", idl[k]));
1722 /* Merge in descending sorted order */
1725 mop[0] = (pgno_t)-1;
1729 for (; old_id < new_id; old_id = mop[--j])
1736 /* Use new pages from the map when nothing suitable in the freeDB */
1738 pgno = txn->mt_next_pgno;
1739 if (pgno + num >= env->me_maxpg) {
1740 DPUTS("DB size maxed out");
1741 return MDB_MAP_FULL;
1745 if (env->me_flags & MDB_WRITEMAP) {
1746 np = (MDB_page *)(env->me_map + env->me_psize * pgno);
1748 if (!(np = mdb_page_malloc(txn, num)))
1752 mop[0] = mop_len -= num;
1753 /* Move any stragglers down */
1754 for (j = i-num; j < mop_len; )
1755 mop[++j] = mop[++i];
1757 txn->mt_next_pgno = pgno + num;
1760 mdb_page_dirty(txn, np);
1766 /** Copy the used portions of a non-overflow page.
1767 * @param[in] dst page to copy into
1768 * @param[in] src page to copy from
1769 * @param[in] psize size of a page
1772 mdb_page_copy(MDB_page *dst, MDB_page *src, unsigned int psize)
1774 enum { Align = sizeof(pgno_t) };
1775 indx_t upper = src->mp_upper, lower = src->mp_lower, unused = upper-lower;
1777 /* If page isn't full, just copy the used portion. Adjust
1778 * alignment so memcpy may copy words instead of bytes.
1780 if ((unused &= -Align) && !IS_LEAF2(src)) {
1782 memcpy(dst, src, (lower + (Align-1)) & -Align);
1783 memcpy((pgno_t *)((char *)dst+upper), (pgno_t *)((char *)src+upper),
1786 memcpy(dst, src, psize - unused);
1790 /** Pull a page off the txn's spill list, if present.
1791 * If a page being referenced was spilled to disk in this txn, bring
1792 * it back and make it dirty/writable again.
1793 * @param[in] tx0 the transaction handle.
1794 * @param[in] mp the page being referenced.
1795 * @param[out] ret the writable page, if any. ret is unchanged if
1796 * mp wasn't spilled.
1799 mdb_page_unspill(MDB_txn *tx0, MDB_page *mp, MDB_page **ret)
1801 MDB_env *env = tx0->mt_env;
1804 pgno_t pgno = mp->mp_pgno, pn = pgno << 1;
1806 for (txn = tx0; txn; txn=txn->mt_parent) {
1807 if (!txn->mt_spill_pgs)
1809 x = mdb_midl_search(txn->mt_spill_pgs, pn);
1810 if (x <= txn->mt_spill_pgs[0] && txn->mt_spill_pgs[x] == pn) {
1813 if (IS_OVERFLOW(mp))
1817 if (env->me_flags & MDB_WRITEMAP) {
1820 np = mdb_page_malloc(txn, num);
1824 memcpy(np, mp, num * env->me_psize);
1826 mdb_page_copy(np, mp, env->me_psize);
1829 /* If in current txn, this page is no longer spilled.
1830 * If it happens to be the last page, truncate the spill list.
1831 * Otherwise mark it as deleted by setting the LSB.
1833 if (x == txn->mt_spill_pgs[0])
1834 txn->mt_spill_pgs[0]--;
1836 txn->mt_spill_pgs[x] |= 1;
1837 } /* otherwise, if belonging to a parent txn, the
1838 * page remains spilled until child commits
1841 if (txn->mt_parent) {
1843 /* If this page is also in a parent's dirty list, then
1844 * it's already accounted in dirty_room, and we need to
1845 * cancel out the decrement that mdb_page_dirty does.
1847 for (tx2 = txn->mt_parent; tx2; tx2 = tx2->mt_parent) {
1848 x = mdb_mid2l_search(tx2->mt_u.dirty_list, pgno);
1849 if (x <= tx2->mt_u.dirty_list[0].mid &&
1850 tx2->mt_u.dirty_list[x].mid == pgno) {
1851 tx0->mt_dirty_room++;
1856 mdb_page_dirty(tx0, np);
1857 np->mp_flags |= P_DIRTY;
1865 /** Touch a page: make it dirty and re-insert into tree with updated pgno.
1866 * @param[in] mc cursor pointing to the page to be touched
1867 * @return 0 on success, non-zero on failure.
1870 mdb_page_touch(MDB_cursor *mc)
1872 MDB_page *mp = mc->mc_pg[mc->mc_top], *np;
1873 MDB_txn *txn = mc->mc_txn;
1874 MDB_cursor *m2, *m3;
1879 if (!F_ISSET(mp->mp_flags, P_DIRTY)) {
1880 if (txn->mt_flags & MDB_TXN_SPILLS) {
1882 rc = mdb_page_unspill(txn, mp, &np);
1888 if ((rc = mdb_midl_need(&txn->mt_free_pgs, 1)) ||
1889 (rc = mdb_page_alloc(mc, 1, &np)))
1892 DPRINTF(("touched db %u page %"Z"u -> %"Z"u", mc->mc_dbi,mp->mp_pgno,pgno));
1893 assert(mp->mp_pgno != pgno);
1894 mdb_midl_xappend(txn->mt_free_pgs, mp->mp_pgno);
1895 /* Update the parent page, if any, to point to the new page */
1897 MDB_page *parent = mc->mc_pg[mc->mc_top-1];
1898 MDB_node *node = NODEPTR(parent, mc->mc_ki[mc->mc_top-1]);
1899 SETPGNO(node, pgno);
1901 mc->mc_db->md_root = pgno;
1903 } else if (txn->mt_parent && !IS_SUBP(mp)) {
1904 MDB_ID2 mid, *dl = txn->mt_u.dirty_list;
1906 /* If txn has a parent, make sure the page is in our
1910 unsigned x = mdb_mid2l_search(dl, pgno);
1911 if (x <= dl[0].mid && dl[x].mid == pgno) {
1912 if (mp != dl[x].mptr) { /* bad cursor? */
1913 mc->mc_flags &= ~(C_INITIALIZED|C_EOF);
1914 return MDB_CORRUPTED;
1919 assert(dl[0].mid < MDB_IDL_UM_MAX);
1921 np = mdb_page_malloc(txn, 1);
1926 mdb_mid2l_insert(dl, &mid);
1931 mdb_page_copy(np, mp, txn->mt_env->me_psize);
1933 np->mp_flags |= P_DIRTY;
1936 /* Adjust cursors pointing to mp */
1937 mc->mc_pg[mc->mc_top] = np;
1939 if (mc->mc_flags & C_SUB) {
1941 for (m2 = txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
1942 m3 = &m2->mc_xcursor->mx_cursor;
1943 if (m3->mc_snum < mc->mc_snum) continue;
1944 if (m3->mc_pg[mc->mc_top] == mp)
1945 m3->mc_pg[mc->mc_top] = np;
1948 for (m2 = txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
1949 if (m2->mc_snum < mc->mc_snum) continue;
1950 if (m2->mc_pg[mc->mc_top] == mp) {
1951 m2->mc_pg[mc->mc_top] = np;
1952 if ((mc->mc_db->md_flags & MDB_DUPSORT) &&
1953 m2->mc_ki[mc->mc_top] == mc->mc_ki[mc->mc_top])
1955 MDB_node *leaf = NODEPTR(np, mc->mc_ki[mc->mc_top]);
1956 if (!(leaf->mn_flags & F_SUBDATA))
1957 m2->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(leaf);
1966 mdb_env_sync(MDB_env *env, int force)
1969 if (force || !F_ISSET(env->me_flags, MDB_NOSYNC)) {
1970 if (env->me_flags & MDB_WRITEMAP) {
1971 int flags = ((env->me_flags & MDB_MAPASYNC) && !force)
1972 ? MS_ASYNC : MS_SYNC;
1973 if (MDB_MSYNC(env->me_map, env->me_mapsize, flags))
1976 else if (flags == MS_SYNC && MDB_FDATASYNC(env->me_fd))
1980 if (MDB_FDATASYNC(env->me_fd))
1987 /** Back up parent txn's cursors, then grab the originals for tracking */
1989 mdb_cursor_shadow(MDB_txn *src, MDB_txn *dst)
1991 MDB_cursor *mc, *bk;
1996 for (i = src->mt_numdbs; --i >= 0; ) {
1997 if ((mc = src->mt_cursors[i]) != NULL) {
1998 size = sizeof(MDB_cursor);
2000 size += sizeof(MDB_xcursor);
2001 for (; mc; mc = bk->mc_next) {
2007 mc->mc_db = &dst->mt_dbs[i];
2008 /* Kill pointers into src - and dst to reduce abuse: The
2009 * user may not use mc until dst ends. Otherwise we'd...
2011 mc->mc_txn = NULL; /* ...set this to dst */
2012 mc->mc_dbflag = NULL; /* ...and &dst->mt_dbflags[i] */
2013 if ((mx = mc->mc_xcursor) != NULL) {
2014 *(MDB_xcursor *)(bk+1) = *mx;
2015 mx->mx_cursor.mc_txn = NULL; /* ...and dst. */
2017 mc->mc_next = dst->mt_cursors[i];
2018 dst->mt_cursors[i] = mc;
2025 /** Close this write txn's cursors, give parent txn's cursors back to parent.
2026 * @param[in] txn the transaction handle.
2027 * @param[in] merge true to keep changes to parent cursors, false to revert.
2028 * @return 0 on success, non-zero on failure.
2031 mdb_cursors_close(MDB_txn *txn, unsigned merge)
2033 MDB_cursor **cursors = txn->mt_cursors, *mc, *next, *bk;
2037 for (i = txn->mt_numdbs; --i >= 0; ) {
2038 for (mc = cursors[i]; mc; mc = next) {
2040 if ((bk = mc->mc_backup) != NULL) {
2042 /* Commit changes to parent txn */
2043 mc->mc_next = bk->mc_next;
2044 mc->mc_backup = bk->mc_backup;
2045 mc->mc_txn = bk->mc_txn;
2046 mc->mc_db = bk->mc_db;
2047 mc->mc_dbflag = bk->mc_dbflag;
2048 if ((mx = mc->mc_xcursor) != NULL)
2049 mx->mx_cursor.mc_txn = bk->mc_txn;
2051 /* Abort nested txn */
2053 if ((mx = mc->mc_xcursor) != NULL)
2054 *mx = *(MDB_xcursor *)(bk+1);
2058 /* Only malloced cursors are permanently tracked. */
2066 #define mdb_txn_reset0(txn, act) mdb_txn_reset0(txn)
2069 mdb_txn_reset0(MDB_txn *txn, const char *act);
2071 #if !(MDB_PIDLOCK) /* Currently the same as defined(_WIN32) */
2077 Pidset = F_SETLK, Pidcheck = F_GETLK
2081 /** Set or check a pid lock. Set returns 0 on success.
2082 * Check returns 0 if the process is certainly dead, nonzero if it may
2083 * be alive (the lock exists or an error happened so we do not know).
2085 * On Windows Pidset is a no-op, we merely check for the existence
2086 * of the process with the given pid. On POSIX we use a single byte
2087 * lock on the lockfile, set at an offset equal to the pid.
2090 mdb_reader_pid(MDB_env *env, enum Pidlock_op op, pid_t pid)
2092 #if !(MDB_PIDLOCK) /* Currently the same as defined(_WIN32) */
2095 if (op == Pidcheck) {
2096 h = OpenProcess(env->me_pidquery, FALSE, pid);
2097 /* No documented "no such process" code, but other program use this: */
2099 return ErrCode() != ERROR_INVALID_PARAMETER;
2100 /* A process exists until all handles to it close. Has it exited? */
2101 ret = WaitForSingleObject(h, 0) != 0;
2108 struct flock lock_info;
2109 memset(&lock_info, 0, sizeof(lock_info));
2110 lock_info.l_type = F_WRLCK;
2111 lock_info.l_whence = SEEK_SET;
2112 lock_info.l_start = pid;
2113 lock_info.l_len = 1;
2114 if ((rc = fcntl(env->me_lfd, op, &lock_info)) == 0) {
2115 if (op == F_GETLK && lock_info.l_type != F_UNLCK)
2117 } else if ((rc = ErrCode()) == EINTR) {
2125 /** Common code for #mdb_txn_begin() and #mdb_txn_renew().
2126 * @param[in] txn the transaction handle to initialize
2127 * @return 0 on success, non-zero on failure.
2130 mdb_txn_renew0(MDB_txn *txn)
2132 MDB_env *env = txn->mt_env;
2135 int rc, new_notls = 0;
2138 txn->mt_numdbs = env->me_numdbs;
2139 txn->mt_dbxs = env->me_dbxs; /* mostly static anyway */
2141 if (txn->mt_flags & MDB_TXN_RDONLY) {
2142 if (!env->me_txns) {
2143 i = mdb_env_pick_meta(env);
2144 txn->mt_txnid = env->me_metas[i]->mm_txnid;
2145 txn->mt_u.reader = NULL;
2147 MDB_reader *r = (env->me_flags & MDB_NOTLS) ? txn->mt_u.reader :
2148 pthread_getspecific(env->me_txkey);
2150 if (r->mr_pid != env->me_pid || r->mr_txnid != (txnid_t)-1)
2151 return MDB_BAD_RSLOT;
2153 pid_t pid = env->me_pid;
2154 pthread_t tid = pthread_self();
2156 if (!(env->me_flags & MDB_LIVE_READER)) {
2157 rc = mdb_reader_pid(env, Pidset, pid);
2159 UNLOCK_MUTEX_R(env);
2162 env->me_flags |= MDB_LIVE_READER;
2166 for (i=0; i<env->me_txns->mti_numreaders; i++)
2167 if (env->me_txns->mti_readers[i].mr_pid == 0)
2169 if (i == env->me_maxreaders) {
2170 UNLOCK_MUTEX_R(env);
2171 return MDB_READERS_FULL;
2173 env->me_txns->mti_readers[i].mr_pid = pid;
2174 env->me_txns->mti_readers[i].mr_tid = tid;
2175 if (i >= env->me_txns->mti_numreaders)
2176 env->me_txns->mti_numreaders = i+1;
2177 /* Save numreaders for un-mutexed mdb_env_close() */
2178 env->me_numreaders = env->me_txns->mti_numreaders;
2179 UNLOCK_MUTEX_R(env);
2180 r = &env->me_txns->mti_readers[i];
2181 new_notls = (env->me_flags & MDB_NOTLS);
2182 if (!new_notls && (rc=pthread_setspecific(env->me_txkey, r))) {
2187 txn->mt_txnid = r->mr_txnid = env->me_txns->mti_txnid;
2188 txn->mt_u.reader = r;
2190 txn->mt_toggle = txn->mt_txnid & 1;
2194 txn->mt_txnid = env->me_txns->mti_txnid;
2195 txn->mt_toggle = txn->mt_txnid & 1;
2198 if (txn->mt_txnid == mdb_debug_start)
2201 txn->mt_dirty_room = MDB_IDL_UM_MAX;
2202 txn->mt_u.dirty_list = env->me_dirty_list;
2203 txn->mt_u.dirty_list[0].mid = 0;
2204 txn->mt_free_pgs = env->me_free_pgs;
2205 txn->mt_free_pgs[0] = 0;
2206 txn->mt_spill_pgs = NULL;
2210 /* Copy the DB info and flags */
2211 memcpy(txn->mt_dbs, env->me_metas[txn->mt_toggle]->mm_dbs, 2 * sizeof(MDB_db));
2213 /* Moved to here to avoid a data race in read TXNs */
2214 txn->mt_next_pgno = env->me_metas[txn->mt_toggle]->mm_last_pg+1;
2216 for (i=2; i<txn->mt_numdbs; i++) {
2217 x = env->me_dbflags[i];
2218 txn->mt_dbs[i].md_flags = x & PERSISTENT_FLAGS;
2219 txn->mt_dbflags[i] = (x & MDB_VALID) ? DB_VALID|DB_STALE : 0;
2221 txn->mt_dbflags[0] = txn->mt_dbflags[1] = DB_VALID;
2223 if (env->me_maxpg < txn->mt_next_pgno) {
2224 mdb_txn_reset0(txn, "renew0-mapfail");
2226 txn->mt_u.reader->mr_pid = 0;
2227 txn->mt_u.reader = NULL;
2229 return MDB_MAP_RESIZED;
2236 mdb_txn_renew(MDB_txn *txn)
2240 if (!txn || txn->mt_dbxs) /* A reset txn has mt_dbxs==NULL */
2243 if (txn->mt_env->me_flags & MDB_FATAL_ERROR) {
2244 DPUTS("environment had fatal error, must shutdown!");
2248 rc = mdb_txn_renew0(txn);
2249 if (rc == MDB_SUCCESS) {
2250 DPRINTF(("renew txn %"Z"u%c %p on mdbenv %p, root page %"Z"u",
2251 txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',
2252 (void *)txn, (void *)txn->mt_env, txn->mt_dbs[MAIN_DBI].md_root));
2258 mdb_txn_begin(MDB_env *env, MDB_txn *parent, unsigned int flags, MDB_txn **ret)
2262 int rc, size, tsize = sizeof(MDB_txn);
2264 if (env->me_flags & MDB_FATAL_ERROR) {
2265 DPUTS("environment had fatal error, must shutdown!");
2268 if ((env->me_flags & MDB_RDONLY) && !(flags & MDB_RDONLY))
2271 /* Nested transactions: Max 1 child, write txns only, no writemap */
2272 if (parent->mt_child ||
2273 (flags & MDB_RDONLY) ||
2274 (parent->mt_flags & (MDB_TXN_RDONLY|MDB_TXN_ERROR)) ||
2275 (env->me_flags & MDB_WRITEMAP))
2277 return (parent->mt_flags & MDB_TXN_RDONLY) ? EINVAL : MDB_BAD_TXN;
2279 tsize = sizeof(MDB_ntxn);
2281 size = tsize + env->me_maxdbs * (sizeof(MDB_db)+1);
2282 if (!(flags & MDB_RDONLY))
2283 size += env->me_maxdbs * sizeof(MDB_cursor *);
2285 if ((txn = calloc(1, size)) == NULL) {
2286 DPRINTF(("calloc: %s", strerror(ErrCode())));
2289 txn->mt_dbs = (MDB_db *) ((char *)txn + tsize);
2290 if (flags & MDB_RDONLY) {
2291 txn->mt_flags |= MDB_TXN_RDONLY;
2292 txn->mt_dbflags = (unsigned char *)(txn->mt_dbs + env->me_maxdbs);
2294 txn->mt_cursors = (MDB_cursor **)(txn->mt_dbs + env->me_maxdbs);
2295 txn->mt_dbflags = (unsigned char *)(txn->mt_cursors + env->me_maxdbs);
2301 txn->mt_u.dirty_list = malloc(sizeof(MDB_ID2)*MDB_IDL_UM_SIZE);
2302 if (!txn->mt_u.dirty_list ||
2303 !(txn->mt_free_pgs = mdb_midl_alloc(MDB_IDL_UM_MAX)))
2305 free(txn->mt_u.dirty_list);
2309 txn->mt_txnid = parent->mt_txnid;
2310 txn->mt_toggle = parent->mt_toggle;
2311 txn->mt_dirty_room = parent->mt_dirty_room;
2312 txn->mt_u.dirty_list[0].mid = 0;
2313 txn->mt_spill_pgs = NULL;
2314 txn->mt_next_pgno = parent->mt_next_pgno;
2315 parent->mt_child = txn;
2316 txn->mt_parent = parent;
2317 txn->mt_numdbs = parent->mt_numdbs;
2318 txn->mt_flags = parent->mt_flags;
2319 txn->mt_dbxs = parent->mt_dbxs;
2320 memcpy(txn->mt_dbs, parent->mt_dbs, txn->mt_numdbs * sizeof(MDB_db));
2321 /* Copy parent's mt_dbflags, but clear DB_NEW */
2322 for (i=0; i<txn->mt_numdbs; i++)
2323 txn->mt_dbflags[i] = parent->mt_dbflags[i] & ~DB_NEW;
2325 ntxn = (MDB_ntxn *)txn;
2326 ntxn->mnt_pgstate = env->me_pgstate; /* save parent me_pghead & co */
2327 if (env->me_pghead) {
2328 size = MDB_IDL_SIZEOF(env->me_pghead);
2329 env->me_pghead = mdb_midl_alloc(env->me_pghead[0]);
2331 memcpy(env->me_pghead, ntxn->mnt_pgstate.mf_pghead, size);
2336 rc = mdb_cursor_shadow(parent, txn);
2338 mdb_txn_reset0(txn, "beginchild-fail");
2340 rc = mdb_txn_renew0(txn);
2346 DPRINTF(("begin txn %"Z"u%c %p on mdbenv %p, root page %"Z"u",
2347 txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',
2348 (void *) txn, (void *) env, txn->mt_dbs[MAIN_DBI].md_root));
2355 mdb_txn_env(MDB_txn *txn)
2357 if(!txn) return NULL;
2361 /** Export or close DBI handles opened in this txn. */
2363 mdb_dbis_update(MDB_txn *txn, int keep)
2366 MDB_dbi n = txn->mt_numdbs;
2367 MDB_env *env = txn->mt_env;
2368 unsigned char *tdbflags = txn->mt_dbflags;
2370 for (i = n; --i >= 2;) {
2371 if (tdbflags[i] & DB_NEW) {
2373 env->me_dbflags[i] = txn->mt_dbs[i].md_flags | MDB_VALID;
2375 char *ptr = env->me_dbxs[i].md_name.mv_data;
2376 env->me_dbxs[i].md_name.mv_data = NULL;
2377 env->me_dbxs[i].md_name.mv_size = 0;
2378 env->me_dbflags[i] = 0;
2383 if (keep && env->me_numdbs < n)
2387 /** Common code for #mdb_txn_reset() and #mdb_txn_abort().
2388 * May be called twice for readonly txns: First reset it, then abort.
2389 * @param[in] txn the transaction handle to reset
2390 * @param[in] act why the transaction is being reset
2393 mdb_txn_reset0(MDB_txn *txn, const char *act)
2395 MDB_env *env = txn->mt_env;
2397 /* Close any DBI handles opened in this txn */
2398 mdb_dbis_update(txn, 0);
2400 DPRINTF(("%s txn %"Z"u%c %p on mdbenv %p, root page %"Z"u",
2401 act, txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',
2402 (void *) txn, (void *)env, txn->mt_dbs[MAIN_DBI].md_root));
2404 if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
2405 if (txn->mt_u.reader) {
2406 txn->mt_u.reader->mr_txnid = (txnid_t)-1;
2407 if (!(env->me_flags & MDB_NOTLS))
2408 txn->mt_u.reader = NULL; /* txn does not own reader */
2410 txn->mt_numdbs = 0; /* close nothing if called again */
2411 txn->mt_dbxs = NULL; /* mark txn as reset */
2413 mdb_cursors_close(txn, 0);
2415 if (!(env->me_flags & MDB_WRITEMAP)) {
2416 mdb_dlist_free(txn);
2418 mdb_midl_free(env->me_pghead);
2420 if (txn->mt_parent) {
2421 txn->mt_parent->mt_child = NULL;
2422 env->me_pgstate = ((MDB_ntxn *)txn)->mnt_pgstate;
2423 mdb_midl_free(txn->mt_free_pgs);
2424 mdb_midl_free(txn->mt_spill_pgs);
2425 free(txn->mt_u.dirty_list);
2429 if (mdb_midl_shrink(&txn->mt_free_pgs))
2430 env->me_free_pgs = txn->mt_free_pgs;
2431 env->me_pghead = NULL;
2435 /* The writer mutex was locked in mdb_txn_begin. */
2436 UNLOCK_MUTEX_W(env);
2441 mdb_txn_reset(MDB_txn *txn)
2446 /* This call is only valid for read-only txns */
2447 if (!(txn->mt_flags & MDB_TXN_RDONLY))
2450 mdb_txn_reset0(txn, "reset");
2454 mdb_txn_abort(MDB_txn *txn)
2460 mdb_txn_abort(txn->mt_child);
2462 mdb_txn_reset0(txn, "abort");
2463 /* Free reader slot tied to this txn (if MDB_NOTLS && writable FS) */
2464 if ((txn->mt_flags & MDB_TXN_RDONLY) && txn->mt_u.reader)
2465 txn->mt_u.reader->mr_pid = 0;
2470 /** Save the freelist as of this transaction to the freeDB.
2471 * This changes the freelist. Keep trying until it stabilizes.
2474 mdb_freelist_save(MDB_txn *txn)
2476 /* env->me_pghead[] can grow and shrink during this call.
2477 * env->me_pglast and txn->mt_free_pgs[] can only grow.
2478 * Page numbers cannot disappear from txn->mt_free_pgs[].
2481 MDB_env *env = txn->mt_env;
2482 int rc, maxfree_1pg = env->me_maxfree_1pg, more = 1;
2483 txnid_t pglast = 0, head_id = 0;
2484 pgno_t freecnt = 0, *free_pgs, *mop;
2485 ssize_t head_room = 0, total_room = 0, mop_len;
2487 mdb_cursor_init(&mc, txn, FREE_DBI, NULL);
2489 if (env->me_pghead) {
2490 /* Make sure first page of freeDB is touched and on freelist */
2491 rc = mdb_page_search(&mc, NULL, MDB_PS_MODIFY);
2492 if (rc && rc != MDB_NOTFOUND)
2497 /* Come back here after each Put() in case freelist changed */
2500 /* If using records from freeDB which we have not yet
2501 * deleted, delete them and any we reserved for me_pghead.
2503 while (pglast < env->me_pglast) {
2504 rc = mdb_cursor_first(&mc, &key, NULL);
2507 pglast = head_id = *(txnid_t *)key.mv_data;
2508 total_room = head_room = 0;
2509 assert(pglast <= env->me_pglast);
2510 rc = mdb_cursor_del(&mc, 0);
2515 /* Save the IDL of pages freed by this txn, to a single record */
2516 if (freecnt < txn->mt_free_pgs[0]) {
2518 /* Make sure last page of freeDB is touched and on freelist */
2519 key.mv_size = MDB_MAXKEYSIZE+1;
2521 rc = mdb_page_search(&mc, &key, MDB_PS_MODIFY);
2522 if (rc && rc != MDB_NOTFOUND)
2525 free_pgs = txn->mt_free_pgs;
2526 /* Write to last page of freeDB */
2527 key.mv_size = sizeof(txn->mt_txnid);
2528 key.mv_data = &txn->mt_txnid;
2530 freecnt = free_pgs[0];
2531 data.mv_size = MDB_IDL_SIZEOF(free_pgs);
2532 rc = mdb_cursor_put(&mc, &key, &data, MDB_RESERVE);
2535 /* Retry if mt_free_pgs[] grew during the Put() */
2536 free_pgs = txn->mt_free_pgs;
2537 } while (freecnt < free_pgs[0]);
2538 mdb_midl_sort(free_pgs);
2539 memcpy(data.mv_data, free_pgs, data.mv_size);
2542 unsigned int i = free_pgs[0];
2543 DPRINTF(("IDL write txn %"Z"u root %"Z"u num %u",
2544 txn->mt_txnid, txn->mt_dbs[FREE_DBI].md_root, i));
2546 DPRINTF(("IDL %"Z"u", free_pgs[i]));
2552 mop = env->me_pghead;
2553 mop_len = mop ? mop[0] : 0;
2555 /* Reserve records for me_pghead[]. Split it if multi-page,
2556 * to avoid searching freeDB for a page range. Use keys in
2557 * range [1,me_pglast]: Smaller than txnid of oldest reader.
2559 if (total_room >= mop_len) {
2560 if (total_room == mop_len || --more < 0)
2562 } else if (head_room >= maxfree_1pg && head_id > 1) {
2563 /* Keep current record (overflow page), add a new one */
2567 /* (Re)write {key = head_id, IDL length = head_room} */
2568 total_room -= head_room;
2569 head_room = mop_len - total_room;
2570 if (head_room > maxfree_1pg && head_id > 1) {
2571 /* Overflow multi-page for part of me_pghead */
2572 head_room /= head_id; /* amortize page sizes */
2573 head_room += maxfree_1pg - head_room % (maxfree_1pg + 1);
2574 } else if (head_room < 0) {
2575 /* Rare case, not bothering to delete this record */
2578 key.mv_size = sizeof(head_id);
2579 key.mv_data = &head_id;
2580 data.mv_size = (head_room + 1) * sizeof(pgno_t);
2581 rc = mdb_cursor_put(&mc, &key, &data, MDB_RESERVE);
2584 *(MDB_ID *)data.mv_data = 0; /* IDL is initially empty */
2585 total_room += head_room;
2588 /* Fill in the reserved, touched me_pghead records */
2594 rc = mdb_cursor_first(&mc, &key, &data);
2595 for (; !rc; rc = mdb_cursor_next(&mc, &key, &data, MDB_NEXT)) {
2596 unsigned flags = MDB_CURRENT;
2597 txnid_t id = *(txnid_t *)key.mv_data;
2598 ssize_t len = (ssize_t)(data.mv_size / sizeof(MDB_ID)) - 1;
2601 assert(len >= 0 && id <= env->me_pglast);
2603 if (len > mop_len) {
2605 data.mv_size = (len + 1) * sizeof(MDB_ID);
2608 data.mv_data = mop -= len;
2611 rc = mdb_cursor_put(&mc, &key, &data, flags);
2613 if (rc || !(mop_len -= len))
2620 /** Flush (some) dirty pages to the map, after clearing their dirty flag.
2621 * @param[in] txn the transaction that's being committed
2622 * @param[in] keep number of initial pages in dirty_list to keep dirty.
2623 * @return 0 on success, non-zero on failure.
2626 mdb_page_flush(MDB_txn *txn, int keep)
2628 MDB_env *env = txn->mt_env;
2629 MDB_ID2L dl = txn->mt_u.dirty_list;
2630 unsigned psize = env->me_psize, j;
2631 int i, pagecount = dl[0].mid, rc;
2632 size_t size = 0, pos = 0;
2634 MDB_page *dp = NULL;
2638 struct iovec iov[MDB_COMMIT_PAGES];
2639 ssize_t wpos = 0, wsize = 0, wres;
2640 size_t next_pos = 1; /* impossible pos, so pos != next_pos */
2646 if (env->me_flags & MDB_WRITEMAP) {
2647 /* Clear dirty flags */
2648 while (++i <= pagecount) {
2650 /* Don't flush this page yet */
2651 if (dp->mp_flags & P_KEEP) {
2652 dp->mp_flags ^= P_KEEP;
2656 dp->mp_flags &= ~P_DIRTY;
2662 /* Write the pages */
2664 if (++i <= pagecount) {
2666 /* Don't flush this page yet */
2667 if (dp->mp_flags & P_KEEP) {
2668 dp->mp_flags ^= P_KEEP;
2673 /* clear dirty flag */
2674 dp->mp_flags &= ~P_DIRTY;
2677 if (IS_OVERFLOW(dp)) size *= dp->mp_pages;
2682 /* Windows actually supports scatter/gather I/O, but only on
2683 * unbuffered file handles. Since we're relying on the OS page
2684 * cache for all our data, that's self-defeating. So we just
2685 * write pages one at a time. We use the ov structure to set
2686 * the write offset, to at least save the overhead of a Seek
2689 DPRINTF(("committing page %"Z"u", pgno));
2690 memset(&ov, 0, sizeof(ov));
2691 ov.Offset = pos & 0xffffffff;
2692 ov.OffsetHigh = pos >> 16 >> 16;
2693 if (!WriteFile(env->me_fd, dp, size, NULL, &ov)) {
2695 DPRINTF(("WriteFile: %d", rc));
2699 /* Write up to MDB_COMMIT_PAGES dirty pages at a time. */
2700 if (pos!=next_pos || n==MDB_COMMIT_PAGES || wsize+size>MAX_WRITE) {
2702 /* Write previous page(s) */
2703 #ifdef MDB_USE_PWRITEV
2704 wres = pwritev(env->me_fd, iov, n, wpos);
2707 wres = pwrite(env->me_fd, iov[0].iov_base, wsize, wpos);
2709 if (lseek(env->me_fd, wpos, SEEK_SET) == -1) {
2711 DPRINTF(("lseek: %s", strerror(rc)));
2714 wres = writev(env->me_fd, iov, n);
2717 if (wres != wsize) {
2720 DPRINTF(("Write error: %s", strerror(rc)));
2722 rc = EIO; /* TODO: Use which error code? */
2723 DPUTS("short write, filesystem full?");
2734 DPRINTF(("committing page %"Z"u", pgno));
2735 next_pos = pos + size;
2736 iov[n].iov_len = size;
2737 iov[n].iov_base = (char *)dp;
2743 for (i = keep; ++i <= pagecount; ) {
2745 /* This is a page we skipped above */
2748 dl[j].mid = dp->mp_pgno;
2751 mdb_dpage_free(env, dp);
2759 mdb_txn_commit(MDB_txn *txn)
2765 assert(txn != NULL);
2766 assert(txn->mt_env != NULL);
2768 if (txn->mt_child) {
2769 rc = mdb_txn_commit(txn->mt_child);
2770 txn->mt_child = NULL;
2777 if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
2778 mdb_dbis_update(txn, 1);
2779 txn->mt_numdbs = 2; /* so txn_abort() doesn't close any new handles */
2784 if (F_ISSET(txn->mt_flags, MDB_TXN_ERROR)) {
2785 DPUTS("error flag is set, can't commit");
2787 txn->mt_parent->mt_flags |= MDB_TXN_ERROR;
2792 if (txn->mt_parent) {
2793 MDB_txn *parent = txn->mt_parent;
2797 /* Append our free list to parent's */
2798 rc = mdb_midl_append_list(&parent->mt_free_pgs, txn->mt_free_pgs);
2801 mdb_midl_free(txn->mt_free_pgs);
2803 parent->mt_next_pgno = txn->mt_next_pgno;
2804 parent->mt_flags = txn->mt_flags;
2806 /* Merge our cursors into parent's and close them */
2807 mdb_cursors_close(txn, 1);
2809 /* Update parent's DB table. */
2810 memcpy(parent->mt_dbs, txn->mt_dbs, txn->mt_numdbs * sizeof(MDB_db));
2811 parent->mt_numdbs = txn->mt_numdbs;
2812 parent->mt_dbflags[0] = txn->mt_dbflags[0];
2813 parent->mt_dbflags[1] = txn->mt_dbflags[1];
2814 for (i=2; i<txn->mt_numdbs; i++) {
2815 /* preserve parent's DB_NEW status */
2816 x = parent->mt_dbflags[i] & DB_NEW;
2817 parent->mt_dbflags[i] = txn->mt_dbflags[i] | x;
2820 dst = parent->mt_u.dirty_list;
2821 src = txn->mt_u.dirty_list;
2822 /* Remove anything in our dirty list from parent's spill list */
2823 if (parent->mt_spill_pgs) {
2824 x = parent->mt_spill_pgs[0];
2826 /* zero out our dirty pages in parent spill list */
2827 for (i=1; i<=src[0].mid; i++) {
2828 MDB_ID pn = src[i].mid << 1;
2829 if (pn < parent->mt_spill_pgs[x])
2831 if (pn > parent->mt_spill_pgs[x]) {
2837 parent->mt_spill_pgs[x] = 0;
2840 /* OK, we had a few hits, squash zeros from the spill list */
2841 if (len < parent->mt_spill_pgs[0]) {
2843 for (y=1; y<=parent->mt_spill_pgs[0]; y++) {
2844 if (parent->mt_spill_pgs[y]) {
2846 parent->mt_spill_pgs[x] = parent->mt_spill_pgs[y];
2851 parent->mt_spill_pgs[0] = len;
2854 /* Find len = length of merging our dirty list with parent's */
2856 dst[0].mid = 0; /* simplify loops */
2857 if (parent->mt_parent) {
2858 len = x + src[0].mid;
2859 y = mdb_mid2l_search(src, dst[x].mid + 1) - 1;
2860 for (i = x; y && i; y--) {
2861 pgno_t yp = src[y].mid;
2862 while (yp < dst[i].mid)
2864 if (yp == dst[i].mid) {
2869 } else { /* Simplify the above for single-ancestor case */
2870 len = MDB_IDL_UM_MAX - txn->mt_dirty_room;
2872 /* Merge our dirty list with parent's */
2874 for (i = len; y; dst[i--] = src[y--]) {
2875 pgno_t yp = src[y].mid;
2876 while (yp < dst[x].mid)
2877 dst[i--] = dst[x--];
2878 if (yp == dst[x].mid)
2879 free(dst[x--].mptr);
2883 free(txn->mt_u.dirty_list);
2884 parent->mt_dirty_room = txn->mt_dirty_room;
2885 if (txn->mt_spill_pgs) {
2886 if (parent->mt_spill_pgs) {
2887 mdb_midl_append_list(&parent->mt_spill_pgs, txn->mt_spill_pgs);
2888 mdb_midl_free(txn->mt_spill_pgs);
2889 mdb_midl_sort(parent->mt_spill_pgs);
2891 parent->mt_spill_pgs = txn->mt_spill_pgs;
2895 parent->mt_child = NULL;
2896 mdb_midl_free(((MDB_ntxn *)txn)->mnt_pgstate.mf_pghead);
2901 if (txn != env->me_txn) {
2902 DPUTS("attempt to commit unknown transaction");
2907 mdb_cursors_close(txn, 0);
2909 if (!txn->mt_u.dirty_list[0].mid &&
2910 !(txn->mt_flags & (MDB_TXN_DIRTY|MDB_TXN_SPILLS)))
2913 DPRINTF(("committing txn %"Z"u %p on mdbenv %p, root page %"Z"u",
2914 txn->mt_txnid, (void*)txn, (void*)env, txn->mt_dbs[MAIN_DBI].md_root));
2916 /* Update DB root pointers */
2917 if (txn->mt_numdbs > 2) {
2921 data.mv_size = sizeof(MDB_db);
2923 mdb_cursor_init(&mc, txn, MAIN_DBI, NULL);
2924 for (i = 2; i < txn->mt_numdbs; i++) {
2925 if (txn->mt_dbflags[i] & DB_DIRTY) {
2926 data.mv_data = &txn->mt_dbs[i];
2927 rc = mdb_cursor_put(&mc, &txn->mt_dbxs[i].md_name, &data, 0);
2934 rc = mdb_freelist_save(txn);
2938 mdb_midl_free(env->me_pghead);
2939 env->me_pghead = NULL;
2940 if (mdb_midl_shrink(&txn->mt_free_pgs))
2941 env->me_free_pgs = txn->mt_free_pgs;
2947 if ((rc = mdb_page_flush(txn, 0)) ||
2948 (rc = mdb_env_sync(env, 0)) ||
2949 (rc = mdb_env_write_meta(txn)))
2955 mdb_dbis_update(txn, 1);
2957 UNLOCK_MUTEX_W(env);
2967 /** Read the environment parameters of a DB environment before
2968 * mapping it into memory.
2969 * @param[in] env the environment handle
2970 * @param[out] meta address of where to store the meta information
2971 * @return 0 on success, non-zero on failure.
2974 mdb_env_read_header(MDB_env *env, MDB_meta *meta)
2981 /* We don't know the page size yet, so use a minimum value.
2982 * Read both meta pages so we can use the latest one.
2985 for (i=off=0; i<2; i++, off = meta->mm_psize) {
2989 memset(&ov, 0, sizeof(ov));
2991 rc = ReadFile(env->me_fd,&pbuf,MDB_PAGESIZE,&len,&ov) ? (int)len : -1;
2992 if (rc == -1 && ErrCode() == ERROR_HANDLE_EOF)
2995 rc = pread(env->me_fd, &pbuf, MDB_PAGESIZE, off);
2997 if (rc != MDB_PAGESIZE) {
2998 if (rc == 0 && off == 0)
3000 rc = rc < 0 ? (int) ErrCode() : MDB_INVALID;
3001 DPRINTF(("read: %s", mdb_strerror(rc)));
3005 p = (MDB_page *)&pbuf;
3007 if (!F_ISSET(p->mp_flags, P_META)) {
3008 DPRINTF(("page %"Z"u not a meta page", p->mp_pgno));
3013 if (m->mm_magic != MDB_MAGIC) {
3014 DPUTS("meta has invalid magic");
3018 if (m->mm_version != MDB_DATA_VERSION) {
3019 DPRINTF(("database is version %u, expected version %u",
3020 m->mm_version, MDB_DATA_VERSION));
3021 return MDB_VERSION_MISMATCH;
3024 if (off == 0 || m->mm_txnid > meta->mm_txnid)
3030 /** Write the environment parameters of a freshly created DB environment.
3031 * @param[in] env the environment handle
3032 * @param[out] meta address of where to store the meta information
3033 * @return 0 on success, non-zero on failure.
3036 mdb_env_init_meta(MDB_env *env, MDB_meta *meta)
3044 memset(&ov, 0, sizeof(ov));
3045 #define DO_PWRITE(rc, fd, ptr, size, len, pos) do { \
3047 rc = WriteFile(fd, ptr, size, &len, &ov); } while(0)
3050 #define DO_PWRITE(rc, fd, ptr, size, len, pos) do { \
3051 len = pwrite(fd, ptr, size, pos); \
3052 rc = (len >= 0); } while(0)
3055 DPUTS("writing new meta page");
3057 psize = env->me_psize;
3059 meta->mm_magic = MDB_MAGIC;
3060 meta->mm_version = MDB_DATA_VERSION;
3061 meta->mm_mapsize = env->me_mapsize;
3062 meta->mm_psize = psize;
3063 meta->mm_last_pg = 1;
3064 meta->mm_flags = env->me_flags & 0xffff;
3065 meta->mm_flags |= MDB_INTEGERKEY;
3066 meta->mm_dbs[0].md_root = P_INVALID;
3067 meta->mm_dbs[1].md_root = P_INVALID;
3069 p = calloc(2, psize);
3071 p->mp_flags = P_META;
3072 *(MDB_meta *)METADATA(p) = *meta;
3074 q = (MDB_page *)((char *)p + psize);
3076 q->mp_flags = P_META;
3077 *(MDB_meta *)METADATA(q) = *meta;
3079 DO_PWRITE(rc, env->me_fd, p, psize * 2, len, 0);
3082 else if ((unsigned) len == psize * 2)
3090 /** Update the environment info to commit a transaction.
3091 * @param[in] txn the transaction that's being committed
3092 * @return 0 on success, non-zero on failure.
3095 mdb_env_write_meta(MDB_txn *txn)
3098 MDB_meta meta, metab, *mp;
3100 int rc, len, toggle;
3109 assert(txn != NULL);
3110 assert(txn->mt_env != NULL);
3112 toggle = !txn->mt_toggle;
3113 DPRINTF(("writing meta page %d for root page %"Z"u",
3114 toggle, txn->mt_dbs[MAIN_DBI].md_root));
3117 mp = env->me_metas[toggle];
3119 if (env->me_flags & MDB_WRITEMAP) {
3120 /* Persist any increases of mapsize config */
3121 if (env->me_mapsize > mp->mm_mapsize)
3122 mp->mm_mapsize = env->me_mapsize;
3123 mp->mm_dbs[0] = txn->mt_dbs[0];
3124 mp->mm_dbs[1] = txn->mt_dbs[1];
3125 mp->mm_last_pg = txn->mt_next_pgno - 1;
3126 mp->mm_txnid = txn->mt_txnid;
3127 if (!(env->me_flags & (MDB_NOMETASYNC|MDB_NOSYNC))) {
3128 rc = (env->me_flags & MDB_MAPASYNC) ? MS_ASYNC : MS_SYNC;
3131 ptr += env->me_psize;
3132 if (MDB_MSYNC(ptr, env->me_psize, rc)) {
3139 metab.mm_txnid = env->me_metas[toggle]->mm_txnid;
3140 metab.mm_last_pg = env->me_metas[toggle]->mm_last_pg;
3142 ptr = (char *)&meta;
3143 if (env->me_mapsize > mp->mm_mapsize) {
3144 /* Persist any increases of mapsize config */
3145 meta.mm_mapsize = env->me_mapsize;
3146 off = offsetof(MDB_meta, mm_mapsize);
3148 off = offsetof(MDB_meta, mm_dbs[0].md_depth);
3150 len = sizeof(MDB_meta) - off;
3153 meta.mm_dbs[0] = txn->mt_dbs[0];
3154 meta.mm_dbs[1] = txn->mt_dbs[1];
3155 meta.mm_last_pg = txn->mt_next_pgno - 1;
3156 meta.mm_txnid = txn->mt_txnid;
3159 off += env->me_psize;
3162 /* Write to the SYNC fd */
3163 mfd = env->me_flags & (MDB_NOSYNC|MDB_NOMETASYNC) ?
3164 env->me_fd : env->me_mfd;
3167 memset(&ov, 0, sizeof(ov));
3169 if (!WriteFile(mfd, ptr, len, (DWORD *)&rc, &ov))
3173 rc = pwrite(mfd, ptr, len, off);
3176 rc = rc < 0 ? ErrCode() : EIO;
3177 DPUTS("write failed, disk error?");
3178 /* On a failure, the pagecache still contains the new data.
3179 * Write some old data back, to prevent it from being used.
3180 * Use the non-SYNC fd; we know it will fail anyway.
3182 meta.mm_last_pg = metab.mm_last_pg;
3183 meta.mm_txnid = metab.mm_txnid;
3185 memset(&ov, 0, sizeof(ov));
3187 WriteFile(env->me_fd, ptr, len, NULL, &ov);
3189 r2 = pwrite(env->me_fd, ptr, len, off);
3190 (void)r2; /* Silence warnings. We don't care about pwrite's return value */
3193 env->me_flags |= MDB_FATAL_ERROR;
3197 /* Memory ordering issues are irrelevant; since the entire writer
3198 * is wrapped by wmutex, all of these changes will become visible
3199 * after the wmutex is unlocked. Since the DB is multi-version,
3200 * readers will get consistent data regardless of how fresh or
3201 * how stale their view of these values is.
3203 env->me_txns->mti_txnid = txn->mt_txnid;
3208 /** Check both meta pages to see which one is newer.
3209 * @param[in] env the environment handle
3210 * @return meta toggle (0 or 1).
3213 mdb_env_pick_meta(const MDB_env *env)
3215 return (env->me_metas[0]->mm_txnid < env->me_metas[1]->mm_txnid);
3219 mdb_env_create(MDB_env **env)
3223 e = calloc(1, sizeof(MDB_env));
3227 e->me_maxreaders = DEFAULT_READERS;
3228 e->me_maxdbs = e->me_numdbs = 2;
3229 e->me_fd = INVALID_HANDLE_VALUE;
3230 e->me_lfd = INVALID_HANDLE_VALUE;
3231 e->me_mfd = INVALID_HANDLE_VALUE;
3232 #ifdef MDB_USE_POSIX_SEM
3233 e->me_rmutex = SEM_FAILED;
3234 e->me_wmutex = SEM_FAILED;
3236 e->me_pid = getpid();
3237 VGMEMP_CREATE(e,0,0);
3243 mdb_env_map(MDB_env *env, void *addr, int newsize)
3246 unsigned int flags = env->me_flags;
3250 LONG sizelo, sizehi;
3251 sizelo = env->me_mapsize & 0xffffffff;
3252 sizehi = env->me_mapsize >> 16 >> 16; /* only needed on Win64 */
3254 /* Windows won't create mappings for zero length files.
3255 * Just allocate the maxsize right now.
3258 if (SetFilePointer(env->me_fd, sizelo, &sizehi, 0) != (DWORD)sizelo
3259 || !SetEndOfFile(env->me_fd)
3260 || SetFilePointer(env->me_fd, 0, NULL, 0) != 0)
3263 mh = CreateFileMapping(env->me_fd, NULL, flags & MDB_WRITEMAP ?
3264 PAGE_READWRITE : PAGE_READONLY,
3265 sizehi, sizelo, NULL);
3268 env->me_map = MapViewOfFileEx(mh, flags & MDB_WRITEMAP ?
3269 FILE_MAP_WRITE : FILE_MAP_READ,
3270 0, 0, env->me_mapsize, addr);
3271 rc = env->me_map ? 0 : ErrCode();
3276 int prot = PROT_READ;
3277 if (flags & MDB_WRITEMAP) {
3279 if (newsize && ftruncate(env->me_fd, env->me_mapsize) < 0)
3282 env->me_map = mmap(addr, env->me_mapsize, prot, MAP_SHARED,
3284 if (env->me_map == MAP_FAILED) {
3288 /* Turn off readahead. It's harmful when the DB is larger than RAM. */
3290 madvise(env->me_map, env->me_mapsize, MADV_RANDOM);
3292 #ifdef POSIX_MADV_RANDOM
3293 posix_madvise(env->me_map, env->me_mapsize, POSIX_MADV_RANDOM);
3294 #endif /* POSIX_MADV_RANDOM */
3295 #endif /* MADV_RANDOM */
3298 /* Can happen because the address argument to mmap() is just a
3299 * hint. mmap() can pick another, e.g. if the range is in use.
3300 * The MAP_FIXED flag would prevent that, but then mmap could
3301 * instead unmap existing pages to make room for the new map.
3303 if (addr && env->me_map != addr)
3304 return EBUSY; /* TODO: Make a new MDB_* error code? */
3306 p = (MDB_page *)env->me_map;
3307 env->me_metas[0] = METADATA(p);
3308 env->me_metas[1] = (MDB_meta *)((char *)env->me_metas[0] + env->me_psize);
3314 mdb_env_set_mapsize(MDB_env *env, size_t size)
3316 /* If env is already open, caller is responsible for making
3317 * sure there are no active txns.
3325 size = env->me_metas[mdb_env_pick_meta(env)]->mm_mapsize;
3326 munmap(env->me_map, env->me_mapsize);
3327 env->me_mapsize = size;
3328 old = (env->me_flags & MDB_FIXEDMAP) ? env->me_map : NULL;
3329 rc = mdb_env_map(env, old, 1);
3333 env->me_mapsize = size;
3335 env->me_maxpg = env->me_mapsize / env->me_psize;
3340 mdb_env_set_maxdbs(MDB_env *env, MDB_dbi dbs)
3344 env->me_maxdbs = dbs + 2; /* Named databases + main and free DB */
3349 mdb_env_set_maxreaders(MDB_env *env, unsigned int readers)
3351 if (env->me_map || readers < 1)
3353 env->me_maxreaders = readers;
3358 mdb_env_get_maxreaders(MDB_env *env, unsigned int *readers)
3360 if (!env || !readers)
3362 *readers = env->me_maxreaders;
3366 /** Further setup required for opening an MDB environment
3369 mdb_env_open2(MDB_env *env)
3371 unsigned int flags = env->me_flags;
3372 int i, newenv = 0, rc;
3376 /* See if we should use QueryLimited */
3378 if ((rc & 0xff) > 5)
3379 env->me_pidquery = MDB_PROCESS_QUERY_LIMITED_INFORMATION;
3381 env->me_pidquery = PROCESS_QUERY_INFORMATION;
3384 memset(&meta, 0, sizeof(meta));
3386 if ((i = mdb_env_read_header(env, &meta)) != 0) {
3389 DPUTS("new mdbenv");
3391 GET_PAGESIZE(env->me_psize);
3393 env->me_psize = meta.mm_psize;
3396 /* Was a mapsize configured? */
3397 if (!env->me_mapsize) {
3398 /* If this is a new environment, take the default,
3399 * else use the size recorded in the existing env.
3401 env->me_mapsize = newenv ? DEFAULT_MAPSIZE : meta.mm_mapsize;
3402 } else if (env->me_mapsize < meta.mm_mapsize) {
3403 /* If the configured size is smaller, make sure it's
3404 * still big enough. Silently round up to minimum if not.
3406 size_t minsize = (meta.mm_last_pg + 1) * meta.mm_psize;
3407 if (env->me_mapsize < minsize)
3408 env->me_mapsize = minsize;
3411 rc = mdb_env_map(env, meta.mm_address, newenv);
3416 if (flags & MDB_FIXEDMAP)
3417 meta.mm_address = env->me_map;
3418 i = mdb_env_init_meta(env, &meta);
3419 if (i != MDB_SUCCESS) {
3423 env->me_maxfree_1pg = (env->me_psize - PAGEHDRSZ) / sizeof(pgno_t) - 1;
3424 env->me_nodemax = (env->me_psize - PAGEHDRSZ) / MDB_MINKEYS;
3426 env->me_maxpg = env->me_mapsize / env->me_psize;
3429 int toggle = mdb_env_pick_meta(env);
3430 MDB_db *db = &env->me_metas[toggle]->mm_dbs[MAIN_DBI];
3432 DPRINTF(("opened database version %u, pagesize %u",
3433 env->me_metas[0]->mm_version, env->me_psize));
3434 DPRINTF(("using meta page %d", toggle));
3435 DPRINTF(("depth: %u", db->md_depth));
3436 DPRINTF(("entries: %"Z"u", db->md_entries));
3437 DPRINTF(("branch pages: %"Z"u", db->md_branch_pages));
3438 DPRINTF(("leaf pages: %"Z"u", db->md_leaf_pages));
3439 DPRINTF(("overflow pages: %"Z"u", db->md_overflow_pages));
3440 DPRINTF(("root: %"Z"u", db->md_root));
3448 /** Release a reader thread's slot in the reader lock table.
3449 * This function is called automatically when a thread exits.
3450 * @param[in] ptr This points to the slot in the reader lock table.
3453 mdb_env_reader_dest(void *ptr)
3455 MDB_reader *reader = ptr;
3461 /** Junk for arranging thread-specific callbacks on Windows. This is
3462 * necessarily platform and compiler-specific. Windows supports up
3463 * to 1088 keys. Let's assume nobody opens more than 64 environments
3464 * in a single process, for now. They can override this if needed.
3466 #ifndef MAX_TLS_KEYS
3467 #define MAX_TLS_KEYS 64
3469 static pthread_key_t mdb_tls_keys[MAX_TLS_KEYS];
3470 static int mdb_tls_nkeys;
3472 static void NTAPI mdb_tls_callback(PVOID module, DWORD reason, PVOID ptr)
3476 case DLL_PROCESS_ATTACH: break;
3477 case DLL_THREAD_ATTACH: break;
3478 case DLL_THREAD_DETACH:
3479 for (i=0; i<mdb_tls_nkeys; i++) {
3480 MDB_reader *r = pthread_getspecific(mdb_tls_keys[i]);
3481 mdb_env_reader_dest(r);
3484 case DLL_PROCESS_DETACH: break;
3489 const PIMAGE_TLS_CALLBACK mdb_tls_cbp __attribute__((section (".CRT$XLB"))) = mdb_tls_callback;
3491 PIMAGE_TLS_CALLBACK mdb_tls_cbp __attribute__((section (".CRT$XLB"))) = mdb_tls_callback;
3495 /* Force some symbol references.
3496 * _tls_used forces the linker to create the TLS directory if not already done
3497 * mdb_tls_cbp prevents whole-program-optimizer from dropping the symbol.
3499 #pragma comment(linker, "/INCLUDE:_tls_used")
3500 #pragma comment(linker, "/INCLUDE:mdb_tls_cbp")
3501 #pragma const_seg(".CRT$XLB")
3502 extern const PIMAGE_TLS_CALLBACK mdb_tls_callback;
3503 const PIMAGE_TLS_CALLBACK mdb_tls_cbp = mdb_tls_callback;
3506 #pragma comment(linker, "/INCLUDE:__tls_used")
3507 #pragma comment(linker, "/INCLUDE:_mdb_tls_cbp")
3508 #pragma data_seg(".CRT$XLB")
3509 PIMAGE_TLS_CALLBACK mdb_tls_cbp = mdb_tls_callback;
3511 #endif /* WIN 32/64 */
3512 #endif /* !__GNUC__ */
3515 /** Downgrade the exclusive lock on the region back to shared */
3517 mdb_env_share_locks(MDB_env *env, int *excl)
3519 int rc = 0, toggle = mdb_env_pick_meta(env);
3521 env->me_txns->mti_txnid = env->me_metas[toggle]->mm_txnid;
3526 /* First acquire a shared lock. The Unlock will
3527 * then release the existing exclusive lock.
3529 memset(&ov, 0, sizeof(ov));
3530 if (!LockFileEx(env->me_lfd, 0, 0, 1, 0, &ov)) {
3533 UnlockFile(env->me_lfd, 0, 0, 1, 0);
3539 struct flock lock_info;
3540 /* The shared lock replaces the existing lock */
3541 memset((void *)&lock_info, 0, sizeof(lock_info));
3542 lock_info.l_type = F_RDLCK;
3543 lock_info.l_whence = SEEK_SET;
3544 lock_info.l_start = 0;
3545 lock_info.l_len = 1;
3546 while ((rc = fcntl(env->me_lfd, F_SETLK, &lock_info)) &&
3547 (rc = ErrCode()) == EINTR) ;
3548 *excl = rc ? -1 : 0; /* error may mean we lost the lock */
3555 /** Try to get exlusive lock, otherwise shared.
3556 * Maintain *excl = -1: no/unknown lock, 0: shared, 1: exclusive.
3559 mdb_env_excl_lock(MDB_env *env, int *excl)
3563 if (LockFile(env->me_lfd, 0, 0, 1, 0)) {
3567 memset(&ov, 0, sizeof(ov));
3568 if (LockFileEx(env->me_lfd, 0, 0, 1, 0, &ov)) {
3575 struct flock lock_info;
3576 memset((void *)&lock_info, 0, sizeof(lock_info));
3577 lock_info.l_type = F_WRLCK;
3578 lock_info.l_whence = SEEK_SET;
3579 lock_info.l_start = 0;
3580 lock_info.l_len = 1;
3581 while ((rc = fcntl(env->me_lfd, F_SETLK, &lock_info)) &&
3582 (rc = ErrCode()) == EINTR) ;
3586 # ifdef MDB_USE_POSIX_SEM
3587 if (*excl < 0) /* always true when !MDB_USE_POSIX_SEM */
3590 lock_info.l_type = F_RDLCK;
3591 while ((rc = fcntl(env->me_lfd, F_SETLKW, &lock_info)) &&
3592 (rc = ErrCode()) == EINTR) ;
3600 #if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
3602 * hash_64 - 64 bit Fowler/Noll/Vo-0 FNV-1a hash code
3604 * @(#) $Revision: 5.1 $
3605 * @(#) $Id: hash_64a.c,v 5.1 2009/06/30 09:01:38 chongo Exp $
3606 * @(#) $Source: /usr/local/src/cmd/fnv/RCS/hash_64a.c,v $
3608 * http://www.isthe.com/chongo/tech/comp/fnv/index.html
3612 * Please do not copyright this code. This code is in the public domain.
3614 * LANDON CURT NOLL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
3615 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO
3616 * EVENT SHALL LANDON CURT NOLL BE LIABLE FOR ANY SPECIAL, INDIRECT OR
3617 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
3618 * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
3619 * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
3620 * PERFORMANCE OF THIS SOFTWARE.
3623 * chongo <Landon Curt Noll> /\oo/\
3624 * http://www.isthe.com/chongo/
3626 * Share and Enjoy! :-)
3629 typedef unsigned long long mdb_hash_t;
3630 #define MDB_HASH_INIT ((mdb_hash_t)0xcbf29ce484222325ULL)
3632 /** perform a 64 bit Fowler/Noll/Vo FNV-1a hash on a buffer
3633 * @param[in] val value to hash
3634 * @param[in] hval initial value for hash
3635 * @return 64 bit hash
3637 * NOTE: To use the recommended 64 bit FNV-1a hash, use MDB_HASH_INIT as the
3638 * hval arg on the first call.
3641 mdb_hash_val(MDB_val *val, mdb_hash_t hval)
3643 unsigned char *s = (unsigned char *)val->mv_data; /* unsigned string */
3644 unsigned char *end = s + val->mv_size;
3646 * FNV-1a hash each octet of the string
3649 /* xor the bottom with the current octet */
3650 hval ^= (mdb_hash_t)*s++;
3652 /* multiply by the 64 bit FNV magic prime mod 2^64 */
3653 hval += (hval << 1) + (hval << 4) + (hval << 5) +
3654 (hval << 7) + (hval << 8) + (hval << 40);
3656 /* return our new hash value */
3660 /** Hash the string and output the encoded hash.
3661 * This uses modified RFC1924 Ascii85 encoding to accommodate systems with
3662 * very short name limits. We don't care about the encoding being reversible,
3663 * we just want to preserve as many bits of the input as possible in a
3664 * small printable string.
3665 * @param[in] str string to hash
3666 * @param[out] encbuf an array of 11 chars to hold the hash
3668 static const char mdb_a85[]= "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{|}~";
3671 mdb_pack85(unsigned long l, char *out)
3675 for (i=0; i<5; i++) {
3676 *out++ = mdb_a85[l % 85];
3682 mdb_hash_enc(MDB_val *val, char *encbuf)
3684 mdb_hash_t h = mdb_hash_val(val, MDB_HASH_INIT);
3686 mdb_pack85(h, encbuf);
3687 mdb_pack85(h>>32, encbuf+5);
3692 /** Open and/or initialize the lock region for the environment.
3693 * @param[in] env The MDB environment.
3694 * @param[in] lpath The pathname of the file used for the lock region.
3695 * @param[in] mode The Unix permissions for the file, if we create it.
3696 * @param[out] excl Resulting file lock type: -1 none, 0 shared, 1 exclusive
3697 * @param[in,out] excl In -1, out lock type: -1 none, 0 shared, 1 exclusive
3698 * @return 0 on success, non-zero on failure.
3701 mdb_env_setup_locks(MDB_env *env, char *lpath, int mode, int *excl)
3704 # define MDB_ERRCODE_ROFS ERROR_WRITE_PROTECT
3706 # define MDB_ERRCODE_ROFS EROFS
3707 #ifdef O_CLOEXEC /* Linux: Open file and set FD_CLOEXEC atomically */
3708 # define MDB_CLOEXEC O_CLOEXEC
3711 # define MDB_CLOEXEC 0
3718 env->me_lfd = CreateFile(lpath, GENERIC_READ|GENERIC_WRITE,
3719 FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, OPEN_ALWAYS,
3720 FILE_ATTRIBUTE_NORMAL, NULL);
3722 env->me_lfd = open(lpath, O_RDWR|O_CREAT|MDB_CLOEXEC, mode);
3724 if (env->me_lfd == INVALID_HANDLE_VALUE) {
3726 if (rc == MDB_ERRCODE_ROFS && (env->me_flags & MDB_RDONLY)) {
3731 #if ! ((MDB_CLOEXEC) || defined(_WIN32))
3732 /* Lose record locks when exec*() */
3733 if ((fdflags = fcntl(env->me_lfd, F_GETFD) | FD_CLOEXEC) >= 0)
3734 fcntl(env->me_lfd, F_SETFD, fdflags);
3737 if (!(env->me_flags & MDB_NOTLS)) {
3738 rc = pthread_key_create(&env->me_txkey, mdb_env_reader_dest);
3741 env->me_flags |= MDB_ENV_TXKEY;
3743 /* Windows TLS callbacks need help finding their TLS info. */
3744 if (mdb_tls_nkeys >= MAX_TLS_KEYS) {
3748 mdb_tls_keys[mdb_tls_nkeys++] = env->me_txkey;
3752 /* Try to get exclusive lock. If we succeed, then
3753 * nobody is using the lock region and we should initialize it.
3755 if ((rc = mdb_env_excl_lock(env, excl))) goto fail;
3758 size = GetFileSize(env->me_lfd, NULL);
3760 size = lseek(env->me_lfd, 0, SEEK_END);
3761 if (size == -1) goto fail_errno;
3763 rsize = (env->me_maxreaders-1) * sizeof(MDB_reader) + sizeof(MDB_txninfo);
3764 if (size < rsize && *excl > 0) {
3766 if (SetFilePointer(env->me_lfd, rsize, NULL, FILE_BEGIN) != rsize
3767 || !SetEndOfFile(env->me_lfd))
3770 if (ftruncate(env->me_lfd, rsize) != 0) goto fail_errno;
3774 size = rsize - sizeof(MDB_txninfo);
3775 env->me_maxreaders = size/sizeof(MDB_reader) + 1;
3780 mh = CreateFileMapping(env->me_lfd, NULL, PAGE_READWRITE,
3782 if (!mh) goto fail_errno;
3783 env->me_txns = MapViewOfFileEx(mh, FILE_MAP_WRITE, 0, 0, rsize, NULL);
3785 if (!env->me_txns) goto fail_errno;
3787 void *m = mmap(NULL, rsize, PROT_READ|PROT_WRITE, MAP_SHARED,
3789 if (m == MAP_FAILED) goto fail_errno;
3795 BY_HANDLE_FILE_INFORMATION stbuf;
3804 if (!mdb_sec_inited) {
3805 InitializeSecurityDescriptor(&mdb_null_sd,
3806 SECURITY_DESCRIPTOR_REVISION);
3807 SetSecurityDescriptorDacl(&mdb_null_sd, TRUE, 0, FALSE);
3808 mdb_all_sa.nLength = sizeof(SECURITY_ATTRIBUTES);
3809 mdb_all_sa.bInheritHandle = FALSE;
3810 mdb_all_sa.lpSecurityDescriptor = &mdb_null_sd;
3813 if (!GetFileInformationByHandle(env->me_lfd, &stbuf)) goto fail_errno;
3814 idbuf.volume = stbuf.dwVolumeSerialNumber;
3815 idbuf.nhigh = stbuf.nFileIndexHigh;
3816 idbuf.nlow = stbuf.nFileIndexLow;
3817 val.mv_data = &idbuf;
3818 val.mv_size = sizeof(idbuf);
3819 mdb_hash_enc(&val, encbuf);
3820 sprintf(env->me_txns->mti_rmname, "Global\\MDBr%s", encbuf);
3821 sprintf(env->me_txns->mti_wmname, "Global\\MDBw%s", encbuf);
3822 env->me_rmutex = CreateMutex(&mdb_all_sa, FALSE, env->me_txns->mti_rmname);
3823 if (!env->me_rmutex) goto fail_errno;
3824 env->me_wmutex = CreateMutex(&mdb_all_sa, FALSE, env->me_txns->mti_wmname);
3825 if (!env->me_wmutex) goto fail_errno;
3826 #elif defined(MDB_USE_POSIX_SEM)
3835 #if defined(__NetBSD__)
3836 #define MDB_SHORT_SEMNAMES 1 /* limited to 14 chars */
3838 if (fstat(env->me_lfd, &stbuf)) goto fail_errno;
3839 idbuf.dev = stbuf.st_dev;
3840 idbuf.ino = stbuf.st_ino;
3841 val.mv_data = &idbuf;
3842 val.mv_size = sizeof(idbuf);
3843 mdb_hash_enc(&val, encbuf);
3844 #ifdef MDB_SHORT_SEMNAMES
3845 encbuf[9] = '\0'; /* drop name from 15 chars to 14 chars */
3847 sprintf(env->me_txns->mti_rmname, "/MDBr%s", encbuf);
3848 sprintf(env->me_txns->mti_wmname, "/MDBw%s", encbuf);
3849 /* Clean up after a previous run, if needed: Try to
3850 * remove both semaphores before doing anything else.
3852 sem_unlink(env->me_txns->mti_rmname);
3853 sem_unlink(env->me_txns->mti_wmname);
3854 env->me_rmutex = sem_open(env->me_txns->mti_rmname,
3855 O_CREAT|O_EXCL, mode, 1);
3856 if (env->me_rmutex == SEM_FAILED) goto fail_errno;
3857 env->me_wmutex = sem_open(env->me_txns->mti_wmname,
3858 O_CREAT|O_EXCL, mode, 1);
3859 if (env->me_wmutex == SEM_FAILED) goto fail_errno;
3860 #else /* MDB_USE_POSIX_SEM */
3861 pthread_mutexattr_t mattr;
3863 if ((rc = pthread_mutexattr_init(&mattr))
3864 || (rc = pthread_mutexattr_setpshared(&mattr, PTHREAD_PROCESS_SHARED))
3865 || (rc = pthread_mutex_init(&env->me_txns->mti_mutex, &mattr))
3866 || (rc = pthread_mutex_init(&env->me_txns->mti_wmutex, &mattr)))
3868 pthread_mutexattr_destroy(&mattr);
3869 #endif /* _WIN32 || MDB_USE_POSIX_SEM */
3871 env->me_txns->mti_magic = MDB_MAGIC;
3872 env->me_txns->mti_format = MDB_LOCK_FORMAT;
3873 env->me_txns->mti_txnid = 0;
3874 env->me_txns->mti_numreaders = 0;
3877 if (env->me_txns->mti_magic != MDB_MAGIC) {
3878 DPUTS("lock region has invalid magic");
3882 if (env->me_txns->mti_format != MDB_LOCK_FORMAT) {
3883 DPRINTF(("lock region has format+version 0x%x, expected 0x%x",
3884 env->me_txns->mti_format, MDB_LOCK_FORMAT));
3885 rc = MDB_VERSION_MISMATCH;
3889 if (rc && rc != EACCES && rc != EAGAIN) {
3893 env->me_rmutex = OpenMutex(SYNCHRONIZE, FALSE, env->me_txns->mti_rmname);
3894 if (!env->me_rmutex) goto fail_errno;
3895 env->me_wmutex = OpenMutex(SYNCHRONIZE, FALSE, env->me_txns->mti_wmname);
3896 if (!env->me_wmutex) goto fail_errno;
3897 #elif defined(MDB_USE_POSIX_SEM)
3898 env->me_rmutex = sem_open(env->me_txns->mti_rmname, 0);
3899 if (env->me_rmutex == SEM_FAILED) goto fail_errno;
3900 env->me_wmutex = sem_open(env->me_txns->mti_wmname, 0);
3901 if (env->me_wmutex == SEM_FAILED) goto fail_errno;
3912 /** The name of the lock file in the DB environment */
3913 #define LOCKNAME "/lock.mdb"
3914 /** The name of the data file in the DB environment */
3915 #define DATANAME "/data.mdb"
3916 /** The suffix of the lock file when no subdir is used */
3917 #define LOCKSUFF "-lock"
3918 /** Only a subset of the @ref mdb_env flags can be changed
3919 * at runtime. Changing other flags requires closing the
3920 * environment and re-opening it with the new flags.
3922 #define CHANGEABLE (MDB_NOSYNC|MDB_NOMETASYNC|MDB_MAPASYNC)
3923 #define CHANGELESS (MDB_FIXEDMAP|MDB_NOSUBDIR|MDB_RDONLY|MDB_WRITEMAP|MDB_NOTLS)
3926 mdb_env_open(MDB_env *env, const char *path, unsigned int flags, mdb_mode_t mode)
3928 int oflags, rc, len, excl = -1;
3929 char *lpath, *dpath;
3931 if (env->me_fd!=INVALID_HANDLE_VALUE || (flags & ~(CHANGEABLE|CHANGELESS)))
3935 if (flags & MDB_NOSUBDIR) {
3936 rc = len + sizeof(LOCKSUFF) + len + 1;
3938 rc = len + sizeof(LOCKNAME) + len + sizeof(DATANAME);
3943 if (flags & MDB_NOSUBDIR) {
3944 dpath = lpath + len + sizeof(LOCKSUFF);
3945 sprintf(lpath, "%s" LOCKSUFF, path);
3946 strcpy(dpath, path);
3948 dpath = lpath + len + sizeof(LOCKNAME);
3949 sprintf(lpath, "%s" LOCKNAME, path);
3950 sprintf(dpath, "%s" DATANAME, path);
3954 flags |= env->me_flags;
3955 if (flags & MDB_RDONLY) {
3956 /* silently ignore WRITEMAP when we're only getting read access */
3957 flags &= ~MDB_WRITEMAP;
3959 if (!((env->me_free_pgs = mdb_midl_alloc(MDB_IDL_UM_MAX)) &&
3960 (env->me_dirty_list = calloc(MDB_IDL_UM_SIZE, sizeof(MDB_ID2)))))
3963 env->me_flags = flags |= MDB_ENV_ACTIVE;
3967 env->me_path = strdup(path);
3968 env->me_dbxs = calloc(env->me_maxdbs, sizeof(MDB_dbx));
3969 env->me_dbflags = calloc(env->me_maxdbs, sizeof(uint16_t));
3970 if (!(env->me_dbxs && env->me_path && env->me_dbflags)) {
3975 /* For RDONLY, get lockfile after we know datafile exists */
3976 if (!F_ISSET(flags, MDB_RDONLY)) {
3977 rc = mdb_env_setup_locks(env, lpath, mode, &excl);
3983 if (F_ISSET(flags, MDB_RDONLY)) {
3984 oflags = GENERIC_READ;
3985 len = OPEN_EXISTING;
3987 oflags = GENERIC_READ|GENERIC_WRITE;
3990 mode = FILE_ATTRIBUTE_NORMAL;
3991 env->me_fd = CreateFile(dpath, oflags, FILE_SHARE_READ|FILE_SHARE_WRITE,
3992 NULL, len, mode, NULL);
3994 if (F_ISSET(flags, MDB_RDONLY))
3997 oflags = O_RDWR | O_CREAT;
3999 env->me_fd = open(dpath, oflags, mode);
4001 if (env->me_fd == INVALID_HANDLE_VALUE) {
4006 if (F_ISSET(flags, MDB_RDONLY)) {
4007 rc = mdb_env_setup_locks(env, lpath, mode, &excl);
4012 if ((rc = mdb_env_open2(env)) == MDB_SUCCESS) {
4013 if (flags & (MDB_RDONLY|MDB_WRITEMAP)) {
4014 env->me_mfd = env->me_fd;
4016 /* Synchronous fd for meta writes. Needed even with
4017 * MDB_NOSYNC/MDB_NOMETASYNC, in case these get reset.
4020 len = OPEN_EXISTING;
4021 env->me_mfd = CreateFile(dpath, oflags,
4022 FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, len,
4023 mode | FILE_FLAG_WRITE_THROUGH, NULL);
4026 env->me_mfd = open(dpath, oflags | MDB_DSYNC, mode);
4028 if (env->me_mfd == INVALID_HANDLE_VALUE) {
4033 DPRINTF(("opened dbenv %p", (void *) env));
4035 rc = mdb_env_share_locks(env, &excl);
4041 mdb_env_close0(env, excl);
4047 /** Destroy resources from mdb_env_open(), clear our readers & DBIs */
4049 mdb_env_close0(MDB_env *env, int excl)
4053 if (!(env->me_flags & MDB_ENV_ACTIVE))
4056 /* Doing this here since me_dbxs may not exist during mdb_env_close */
4057 for (i = env->me_maxdbs; --i > MAIN_DBI; )
4058 free(env->me_dbxs[i].md_name.mv_data);
4060 free(env->me_dbflags);
4063 free(env->me_dirty_list);
4064 mdb_midl_free(env->me_free_pgs);
4066 if (env->me_flags & MDB_ENV_TXKEY) {
4067 pthread_key_delete(env->me_txkey);
4069 /* Delete our key from the global list */
4070 for (i=0; i<mdb_tls_nkeys; i++)
4071 if (mdb_tls_keys[i] == env->me_txkey) {
4072 mdb_tls_keys[i] = mdb_tls_keys[mdb_tls_nkeys-1];
4080 munmap(env->me_map, env->me_mapsize);
4082 if (env->me_mfd != env->me_fd && env->me_mfd != INVALID_HANDLE_VALUE)
4083 (void) close(env->me_mfd);
4084 if (env->me_fd != INVALID_HANDLE_VALUE)
4085 (void) close(env->me_fd);
4087 pid_t pid = env->me_pid;
4088 /* Clearing readers is done in this function because
4089 * me_txkey with its destructor must be disabled first.
4091 for (i = env->me_numreaders; --i >= 0; )
4092 if (env->me_txns->mti_readers[i].mr_pid == pid)
4093 env->me_txns->mti_readers[i].mr_pid = 0;
4095 if (env->me_rmutex) {
4096 CloseHandle(env->me_rmutex);
4097 if (env->me_wmutex) CloseHandle(env->me_wmutex);
4099 /* Windows automatically destroys the mutexes when
4100 * the last handle closes.
4102 #elif defined(MDB_USE_POSIX_SEM)
4103 if (env->me_rmutex != SEM_FAILED) {
4104 sem_close(env->me_rmutex);
4105 if (env->me_wmutex != SEM_FAILED)
4106 sem_close(env->me_wmutex);
4107 /* If we have the filelock: If we are the
4108 * only remaining user, clean up semaphores.
4111 mdb_env_excl_lock(env, &excl);
4113 sem_unlink(env->me_txns->mti_rmname);
4114 sem_unlink(env->me_txns->mti_wmname);
4118 munmap((void *)env->me_txns, (env->me_maxreaders-1)*sizeof(MDB_reader)+sizeof(MDB_txninfo));
4120 if (env->me_lfd != INVALID_HANDLE_VALUE) {
4123 /* Unlock the lockfile. Windows would have unlocked it
4124 * after closing anyway, but not necessarily at once.
4126 UnlockFile(env->me_lfd, 0, 0, 1, 0);
4129 (void) close(env->me_lfd);
4132 env->me_flags &= ~(MDB_ENV_ACTIVE|MDB_ENV_TXKEY);
4136 mdb_env_copyfd(MDB_env *env, HANDLE fd)
4138 MDB_txn *txn = NULL;
4144 #define DO_WRITE(rc, fd, ptr, w2, len) rc = WriteFile(fd, ptr, w2, &len, NULL)
4148 #define DO_WRITE(rc, fd, ptr, w2, len) len = write(fd, ptr, w2); rc = (len >= 0)
4151 /* Do the lock/unlock of the reader mutex before starting the
4152 * write txn. Otherwise other read txns could block writers.
4154 rc = mdb_txn_begin(env, NULL, MDB_RDONLY, &txn);
4159 /* We must start the actual read txn after blocking writers */
4160 mdb_txn_reset0(txn, "reset-stage1");
4162 /* Temporarily block writers until we snapshot the meta pages */
4165 rc = mdb_txn_renew0(txn);
4167 UNLOCK_MUTEX_W(env);
4172 wsize = env->me_psize * 2;
4176 DO_WRITE(rc, fd, ptr, w2, len);
4180 } else if (len > 0) {
4186 /* Non-blocking or async handles are not supported */
4192 UNLOCK_MUTEX_W(env);
4197 wsize = txn->mt_next_pgno * env->me_psize - wsize;
4199 if (wsize > MAX_WRITE)
4203 DO_WRITE(rc, fd, ptr, w2, len);
4207 } else if (len > 0) {
4224 mdb_env_copy(MDB_env *env, const char *path)
4228 HANDLE newfd = INVALID_HANDLE_VALUE;
4230 if (env->me_flags & MDB_NOSUBDIR) {
4231 lpath = (char *)path;
4234 len += sizeof(DATANAME);
4235 lpath = malloc(len);
4238 sprintf(lpath, "%s" DATANAME, path);
4241 /* The destination path must exist, but the destination file must not.
4242 * We don't want the OS to cache the writes, since the source data is
4243 * already in the OS cache.
4246 newfd = CreateFile(lpath, GENERIC_WRITE, 0, NULL, CREATE_NEW,
4247 FILE_FLAG_NO_BUFFERING|FILE_FLAG_WRITE_THROUGH, NULL);
4249 newfd = open(lpath, O_WRONLY|O_CREAT|O_EXCL
4255 if (newfd == INVALID_HANDLE_VALUE) {
4260 #ifdef F_NOCACHE /* __APPLE__ */
4261 rc = fcntl(newfd, F_NOCACHE, 1);
4268 rc = mdb_env_copyfd(env, newfd);
4271 if (!(env->me_flags & MDB_NOSUBDIR))
4273 if (newfd != INVALID_HANDLE_VALUE)
4274 if (close(newfd) < 0 && rc == MDB_SUCCESS)
4281 mdb_env_close(MDB_env *env)
4288 VGMEMP_DESTROY(env);
4289 while ((dp = env->me_dpages) != NULL) {
4290 VGMEMP_DEFINED(&dp->mp_next, sizeof(dp->mp_next));
4291 env->me_dpages = dp->mp_next;
4295 mdb_env_close0(env, 0);
4299 /** Compare two items pointing at aligned size_t's */
4301 mdb_cmp_long(const MDB_val *a, const MDB_val *b)
4303 return (*(size_t *)a->mv_data < *(size_t *)b->mv_data) ? -1 :
4304 *(size_t *)a->mv_data > *(size_t *)b->mv_data;
4307 /** Compare two items pointing at aligned int's */
4309 mdb_cmp_int(const MDB_val *a, const MDB_val *b)
4311 return (*(unsigned int *)a->mv_data < *(unsigned int *)b->mv_data) ? -1 :
4312 *(unsigned int *)a->mv_data > *(unsigned int *)b->mv_data;
4315 /** Compare two items pointing at ints of unknown alignment.
4316 * Nodes and keys are guaranteed to be 2-byte aligned.
4319 mdb_cmp_cint(const MDB_val *a, const MDB_val *b)
4321 #if BYTE_ORDER == LITTLE_ENDIAN
4322 unsigned short *u, *c;
4325 u = (unsigned short *) ((char *) a->mv_data + a->mv_size);
4326 c = (unsigned short *) ((char *) b->mv_data + a->mv_size);
4329 } while(!x && u > (unsigned short *)a->mv_data);
4332 return memcmp(a->mv_data, b->mv_data, a->mv_size);
4336 /** Compare two items lexically */
4338 mdb_cmp_memn(const MDB_val *a, const MDB_val *b)
4345 len_diff = (ssize_t) a->mv_size - (ssize_t) b->mv_size;
4351 diff = memcmp(a->mv_data, b->mv_data, len);
4352 return diff ? diff : len_diff<0 ? -1 : len_diff;
4355 /** Compare two items in reverse byte order */
4357 mdb_cmp_memnr(const MDB_val *a, const MDB_val *b)
4359 const unsigned char *p1, *p2, *p1_lim;
4363 p1_lim = (const unsigned char *)a->mv_data;
4364 p1 = (const unsigned char *)a->mv_data + a->mv_size;
4365 p2 = (const unsigned char *)b->mv_data + b->mv_size;
4367 len_diff = (ssize_t) a->mv_size - (ssize_t) b->mv_size;
4373 while (p1 > p1_lim) {
4374 diff = *--p1 - *--p2;
4378 return len_diff<0 ? -1 : len_diff;
4381 /** Search for key within a page, using binary search.
4382 * Returns the smallest entry larger or equal to the key.
4383 * If exactp is non-null, stores whether the found entry was an exact match
4384 * in *exactp (1 or 0).
4385 * Updates the cursor index with the index of the found entry.
4386 * If no entry larger or equal to the key is found, returns NULL.
4389 mdb_node_search(MDB_cursor *mc, MDB_val *key, int *exactp)
4391 unsigned int i = 0, nkeys;
4394 MDB_page *mp = mc->mc_pg[mc->mc_top];
4395 MDB_node *node = NULL;
4400 nkeys = NUMKEYS(mp);
4405 COPY_PGNO(pgno, mp->mp_pgno);
4406 DPRINTF(("searching %u keys in %s %spage %"Z"u",
4407 nkeys, IS_LEAF(mp) ? "leaf" : "branch", IS_SUBP(mp) ? "sub-" : "",
4414 low = IS_LEAF(mp) ? 0 : 1;
4416 cmp = mc->mc_dbx->md_cmp;
4418 /* Branch pages have no data, so if using integer keys,
4419 * alignment is guaranteed. Use faster mdb_cmp_int.
4421 if (cmp == mdb_cmp_cint && IS_BRANCH(mp)) {
4422 if (NODEPTR(mp, 1)->mn_ksize == sizeof(size_t))
4429 nodekey.mv_size = mc->mc_db->md_pad;
4430 node = NODEPTR(mp, 0); /* fake */
4431 while (low <= high) {
4432 i = (low + high) >> 1;
4433 nodekey.mv_data = LEAF2KEY(mp, i, nodekey.mv_size);
4434 rc = cmp(key, &nodekey);
4435 DPRINTF(("found leaf index %u [%s], rc = %i",
4436 i, DKEY(&nodekey), rc));
4445 while (low <= high) {
4446 i = (low + high) >> 1;
4448 node = NODEPTR(mp, i);
4449 nodekey.mv_size = NODEKSZ(node);
4450 nodekey.mv_data = NODEKEY(node);
4452 rc = cmp(key, &nodekey);
4455 DPRINTF(("found leaf index %u [%s], rc = %i",
4456 i, DKEY(&nodekey), rc));
4458 DPRINTF(("found branch index %u [%s -> %"Z"u], rc = %i",
4459 i, DKEY(&nodekey), NODEPGNO(node), rc));
4470 if (rc > 0) { /* Found entry is less than the key. */
4471 i++; /* Skip to get the smallest entry larger than key. */
4473 node = NODEPTR(mp, i);
4476 *exactp = (rc == 0);
4477 /* store the key index */
4478 mc->mc_ki[mc->mc_top] = i;
4480 /* There is no entry larger or equal to the key. */
4483 /* nodeptr is fake for LEAF2 */
4489 mdb_cursor_adjust(MDB_cursor *mc, func)
4493 for (m2 = mc->mc_txn->mt_cursors[mc->mc_dbi]; m2; m2=m2->mc_next) {
4494 if (m2->mc_pg[m2->mc_top] == mc->mc_pg[mc->mc_top]) {
4501 /** Pop a page off the top of the cursor's stack. */
4503 mdb_cursor_pop(MDB_cursor *mc)
4507 MDB_page *top = mc->mc_pg[mc->mc_top];
4513 DPRINTF(("popped page %"Z"u off db %u cursor %p", top->mp_pgno,
4514 mc->mc_dbi, (void *) mc));
4518 /** Push a page onto the top of the cursor's stack. */
4520 mdb_cursor_push(MDB_cursor *mc, MDB_page *mp)
4522 DPRINTF(("pushing page %"Z"u on db %u cursor %p", mp->mp_pgno,
4523 mc->mc_dbi, (void *) mc));
4525 if (mc->mc_snum >= CURSOR_STACK) {
4526 assert(mc->mc_snum < CURSOR_STACK);
4527 return MDB_CURSOR_FULL;
4530 mc->mc_top = mc->mc_snum++;
4531 mc->mc_pg[mc->mc_top] = mp;
4532 mc->mc_ki[mc->mc_top] = 0;
4537 /** Find the address of the page corresponding to a given page number.
4538 * @param[in] txn the transaction for this access.
4539 * @param[in] pgno the page number for the page to retrieve.
4540 * @param[out] ret address of a pointer where the page's address will be stored.
4541 * @param[out] lvl dirty_list inheritance level of found page. 1=current txn, 0=mapped page.
4542 * @return 0 on success, non-zero on failure.
4545 mdb_page_get(MDB_txn *txn, pgno_t pgno, MDB_page **ret, int *lvl)
4547 MDB_env *env = txn->mt_env;
4551 if (!((txn->mt_flags & MDB_TXN_RDONLY) | (env->me_flags & MDB_WRITEMAP))) {
4555 MDB_ID2L dl = tx2->mt_u.dirty_list;
4557 /* Spilled pages were dirtied in this txn and flushed
4558 * because the dirty list got full. Bring this page
4559 * back in from the map (but don't unspill it here,
4560 * leave that unless page_touch happens again).
4562 if (tx2->mt_spill_pgs) {
4563 MDB_ID pn = pgno << 1;
4564 x = mdb_midl_search(tx2->mt_spill_pgs, pn);
4565 if (x <= tx2->mt_spill_pgs[0] && tx2->mt_spill_pgs[x] == pn) {
4566 p = (MDB_page *)(env->me_map + env->me_psize * pgno);
4571 unsigned x = mdb_mid2l_search(dl, pgno);
4572 if (x <= dl[0].mid && dl[x].mid == pgno) {
4578 } while ((tx2 = tx2->mt_parent) != NULL);
4581 if (pgno < txn->mt_next_pgno) {
4583 p = (MDB_page *)(env->me_map + env->me_psize * pgno);
4585 DPRINTF(("page %"Z"u not found", pgno));
4587 return MDB_PAGE_NOTFOUND;
4597 /** Search for the page a given key should be in.
4598 * Pushes parent pages on the cursor stack. This function continues a
4599 * search on a cursor that has already been initialized. (Usually by
4600 * #mdb_page_search() but also by #mdb_node_move().)
4601 * @param[in,out] mc the cursor for this operation.
4602 * @param[in] key the key to search for. If NULL, search for the lowest
4603 * page. (This is used by #mdb_cursor_first().)
4604 * @param[in] modify If true, visited pages are updated with new page numbers.
4605 * @return 0 on success, non-zero on failure.
4608 mdb_page_search_root(MDB_cursor *mc, MDB_val *key, int modify)
4610 MDB_page *mp = mc->mc_pg[mc->mc_top];
4614 while (IS_BRANCH(mp)) {
4618 DPRINTF(("branch page %"Z"u has %u keys", mp->mp_pgno, NUMKEYS(mp)));
4619 assert(NUMKEYS(mp) > 1);
4620 DPRINTF(("found index 0 to page %"Z"u", NODEPGNO(NODEPTR(mp, 0))));
4622 if (key == NULL) /* Initialize cursor to first page. */
4624 else if (key->mv_size > MDB_MAXKEYSIZE && key->mv_data == NULL) {
4625 /* cursor to last page */
4629 node = mdb_node_search(mc, key, &exact);
4631 i = NUMKEYS(mp) - 1;
4633 i = mc->mc_ki[mc->mc_top];
4642 DPRINTF(("following index %u for key [%s]", i, DKEY(key)));
4643 assert(i < NUMKEYS(mp));
4644 node = NODEPTR(mp, i);
4646 if ((rc = mdb_page_get(mc->mc_txn, NODEPGNO(node), &mp, NULL)) != 0)
4649 mc->mc_ki[mc->mc_top] = i;
4650 if ((rc = mdb_cursor_push(mc, mp)))
4654 if ((rc = mdb_page_touch(mc)) != 0)
4656 mp = mc->mc_pg[mc->mc_top];
4661 DPRINTF(("internal error, index points to a %02X page!?",
4663 return MDB_CORRUPTED;
4666 DPRINTF(("found leaf page %"Z"u for key [%s]", mp->mp_pgno,
4667 key ? DKEY(key) : NULL));
4668 mc->mc_flags |= C_INITIALIZED;
4669 mc->mc_flags &= ~C_EOF;
4674 /** Search for the lowest key under the current branch page.
4675 * This just bypasses a NUMKEYS check in the current page
4676 * before calling mdb_page_search_root(), because the callers
4677 * are all in situations where the current page is known to
4681 mdb_page_search_lowest(MDB_cursor *mc)
4683 MDB_page *mp = mc->mc_pg[mc->mc_top];
4684 MDB_node *node = NODEPTR(mp, 0);
4687 if ((rc = mdb_page_get(mc->mc_txn, NODEPGNO(node), &mp, NULL)) != 0)
4690 mc->mc_ki[mc->mc_top] = 0;
4691 if ((rc = mdb_cursor_push(mc, mp)))
4693 return mdb_page_search_root(mc, NULL, 0);
4696 /** Search for the page a given key should be in.
4697 * Pushes parent pages on the cursor stack. This function just sets up
4698 * the search; it finds the root page for \b mc's database and sets this
4699 * as the root of the cursor's stack. Then #mdb_page_search_root() is
4700 * called to complete the search.
4701 * @param[in,out] mc the cursor for this operation.
4702 * @param[in] key the key to search for. If NULL, search for the lowest
4703 * page. (This is used by #mdb_cursor_first().)
4704 * @param[in] flags If MDB_PS_MODIFY set, visited pages are updated with new page numbers.
4705 * If MDB_PS_ROOTONLY set, just fetch root node, no further lookups.
4706 * @return 0 on success, non-zero on failure.
4709 mdb_page_search(MDB_cursor *mc, MDB_val *key, int flags)
4714 /* Make sure the txn is still viable, then find the root from
4715 * the txn's db table.
4717 if (F_ISSET(mc->mc_txn->mt_flags, MDB_TXN_ERROR)) {
4718 DPUTS("transaction has failed, must abort");
4721 /* Make sure we're using an up-to-date root */
4722 if (mc->mc_dbi > MAIN_DBI) {
4723 if ((*mc->mc_dbflag & DB_STALE) ||
4724 ((flags & MDB_PS_MODIFY) && !(*mc->mc_dbflag & DB_DIRTY))) {
4726 unsigned char dbflag = 0;
4727 mdb_cursor_init(&mc2, mc->mc_txn, MAIN_DBI, NULL);
4728 rc = mdb_page_search(&mc2, &mc->mc_dbx->md_name, flags & MDB_PS_MODIFY);
4731 if (*mc->mc_dbflag & DB_STALE) {
4735 MDB_node *leaf = mdb_node_search(&mc2,
4736 &mc->mc_dbx->md_name, &exact);
4738 return MDB_NOTFOUND;
4739 rc = mdb_node_read(mc->mc_txn, leaf, &data);
4742 memcpy(&flags, ((char *) data.mv_data + offsetof(MDB_db, md_flags)),
4744 /* The txn may not know this DBI, or another process may
4745 * have dropped and recreated the DB with other flags.
4747 if ((mc->mc_db->md_flags & PERSISTENT_FLAGS) != flags)
4748 return MDB_INCOMPATIBLE;
4749 memcpy(mc->mc_db, data.mv_data, sizeof(MDB_db));
4751 if (flags & MDB_PS_MODIFY)
4753 *mc->mc_dbflag &= ~DB_STALE;
4754 *mc->mc_dbflag |= dbflag;
4757 root = mc->mc_db->md_root;
4759 if (root == P_INVALID) { /* Tree is empty. */
4760 DPUTS("tree is empty");
4761 return MDB_NOTFOUND;
4766 if (!mc->mc_pg[0] || mc->mc_pg[0]->mp_pgno != root)
4767 if ((rc = mdb_page_get(mc->mc_txn, root, &mc->mc_pg[0], NULL)) != 0)
4773 DPRINTF(("db %u root page %"Z"u has flags 0x%X",
4774 mc->mc_dbi, root, mc->mc_pg[0]->mp_flags));
4776 if (flags & MDB_PS_MODIFY) {
4777 if ((rc = mdb_page_touch(mc)))
4781 if (flags & MDB_PS_ROOTONLY)
4784 return mdb_page_search_root(mc, key, flags);
4788 mdb_ovpage_free(MDB_cursor *mc, MDB_page *mp)
4790 MDB_txn *txn = mc->mc_txn;
4791 pgno_t pg = mp->mp_pgno;
4792 unsigned x = 0, ovpages = mp->mp_pages;
4793 MDB_env *env = txn->mt_env;
4794 MDB_IDL sl = txn->mt_spill_pgs;
4795 MDB_ID pn = pg << 1;
4798 DPRINTF(("free ov page %"Z"u (%d)", pg, ovpages));
4799 /* If the page is dirty or on the spill list we just acquired it,
4800 * so we should give it back to our current free list, if any.
4801 * Otherwise put it onto the list of pages we freed in this txn.
4803 * Won't create me_pghead: me_pglast must be inited along with it.
4804 * Unsupported in nested txns: They would need to hide the page
4805 * range in ancestor txns' dirty and spilled lists.
4807 if (env->me_pghead &&
4809 ((mp->mp_flags & P_DIRTY) ||
4810 (sl && (x = mdb_midl_search(sl, pn)) <= sl[0] && sl[x] == pn)))
4814 MDB_ID2 *dl, ix, iy;
4815 rc = mdb_midl_need(&env->me_pghead, ovpages);
4818 if (!(mp->mp_flags & P_DIRTY)) {
4819 /* This page is no longer spilled */
4826 /* Remove from dirty list */
4827 dl = txn->mt_u.dirty_list;
4829 for (ix = dl[x]; ix.mptr != mp; ix = iy) {
4837 dl[j] = ix; /* Unsorted. OK when MDB_TXN_ERROR. */
4838 txn->mt_flags |= MDB_TXN_ERROR;
4839 return MDB_CORRUPTED;
4842 if (!(env->me_flags & MDB_WRITEMAP))
4843 mdb_dpage_free(env, mp);
4845 /* Insert in me_pghead */
4846 mop = env->me_pghead;
4847 j = mop[0] + ovpages;
4848 for (i = mop[0]; i && mop[i] < pg; i--)
4854 rc = mdb_midl_append_range(&txn->mt_free_pgs, pg, ovpages);
4858 mc->mc_db->md_overflow_pages -= ovpages;
4862 /** Return the data associated with a given node.
4863 * @param[in] txn The transaction for this operation.
4864 * @param[in] leaf The node being read.
4865 * @param[out] data Updated to point to the node's data.
4866 * @return 0 on success, non-zero on failure.
4869 mdb_node_read(MDB_txn *txn, MDB_node *leaf, MDB_val *data)
4871 MDB_page *omp; /* overflow page */
4875 if (!F_ISSET(leaf->mn_flags, F_BIGDATA)) {
4876 data->mv_size = NODEDSZ(leaf);
4877 data->mv_data = NODEDATA(leaf);
4881 /* Read overflow data.
4883 data->mv_size = NODEDSZ(leaf);
4884 memcpy(&pgno, NODEDATA(leaf), sizeof(pgno));
4885 if ((rc = mdb_page_get(txn, pgno, &omp, NULL)) != 0) {
4886 DPRINTF(("read overflow page %"Z"u failed", pgno));
4889 data->mv_data = METADATA(omp);
4895 mdb_get(MDB_txn *txn, MDB_dbi dbi,
4896 MDB_val *key, MDB_val *data)
4905 DPRINTF(("===> get db %u key [%s]", dbi, DKEY(key)));
4907 if (txn == NULL || !dbi || dbi >= txn->mt_numdbs || !(txn->mt_dbflags[dbi] & DB_VALID))
4910 if (txn->mt_flags & MDB_TXN_ERROR)
4913 if (key->mv_size == 0 || key->mv_size > MDB_MAXKEYSIZE) {
4914 return MDB_BAD_VALSIZE;
4917 mdb_cursor_init(&mc, txn, dbi, &mx);
4918 return mdb_cursor_set(&mc, key, data, MDB_SET, &exact);
4921 /** Find a sibling for a page.
4922 * Replaces the page at the top of the cursor's stack with the
4923 * specified sibling, if one exists.
4924 * @param[in] mc The cursor for this operation.
4925 * @param[in] move_right Non-zero if the right sibling is requested,
4926 * otherwise the left sibling.
4927 * @return 0 on success, non-zero on failure.
4930 mdb_cursor_sibling(MDB_cursor *mc, int move_right)
4936 if (mc->mc_snum < 2) {
4937 return MDB_NOTFOUND; /* root has no siblings */
4941 DPRINTF(("parent page is page %"Z"u, index %u",
4942 mc->mc_pg[mc->mc_top]->mp_pgno, mc->mc_ki[mc->mc_top]));
4944 if (move_right ? (mc->mc_ki[mc->mc_top] + 1u >= NUMKEYS(mc->mc_pg[mc->mc_top]))
4945 : (mc->mc_ki[mc->mc_top] == 0)) {
4946 DPRINTF(("no more keys left, moving to %s sibling",
4947 move_right ? "right" : "left"));
4948 if ((rc = mdb_cursor_sibling(mc, move_right)) != MDB_SUCCESS) {
4949 /* undo cursor_pop before returning */
4956 mc->mc_ki[mc->mc_top]++;
4958 mc->mc_ki[mc->mc_top]--;
4959 DPRINTF(("just moving to %s index key %u",
4960 move_right ? "right" : "left", mc->mc_ki[mc->mc_top]));
4962 assert(IS_BRANCH(mc->mc_pg[mc->mc_top]));
4964 indx = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
4965 if ((rc = mdb_page_get(mc->mc_txn, NODEPGNO(indx), &mp, NULL) != 0))
4968 mdb_cursor_push(mc, mp);
4970 mc->mc_ki[mc->mc_top] = NUMKEYS(mp)-1;
4975 /** Move the cursor to the next data item. */
4977 mdb_cursor_next(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op)
4983 if (mc->mc_flags & C_EOF) {
4984 return MDB_NOTFOUND;
4987 assert(mc->mc_flags & C_INITIALIZED);
4989 mp = mc->mc_pg[mc->mc_top];
4991 if (mc->mc_db->md_flags & MDB_DUPSORT) {
4992 leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
4993 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
4994 if (op == MDB_NEXT || op == MDB_NEXT_DUP) {
4995 rc = mdb_cursor_next(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_NEXT);
4996 if (op != MDB_NEXT || rc != MDB_NOTFOUND) {
4997 if (rc == MDB_SUCCESS)
4998 MDB_GET_KEY(leaf, key);
5003 mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
5004 if (op == MDB_NEXT_DUP)
5005 return MDB_NOTFOUND;
5009 DPRINTF(("cursor_next: top page is %"Z"u in cursor %p", mp->mp_pgno, (void *) mc));
5010 if (mc->mc_flags & C_DEL)
5013 if (mc->mc_ki[mc->mc_top] + 1u >= NUMKEYS(mp)) {
5014 DPUTS("=====> move to next sibling page");
5015 if ((rc = mdb_cursor_sibling(mc, 1)) != MDB_SUCCESS) {
5016 mc->mc_flags |= C_EOF;
5019 mp = mc->mc_pg[mc->mc_top];
5020 DPRINTF(("next page is %"Z"u, key index %u", mp->mp_pgno, mc->mc_ki[mc->mc_top]));
5022 mc->mc_ki[mc->mc_top]++;
5025 DPRINTF(("==> cursor points to page %"Z"u with %u keys, key index %u",
5026 mp->mp_pgno, NUMKEYS(mp), mc->mc_ki[mc->mc_top]));
5029 key->mv_size = mc->mc_db->md_pad;
5030 key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
5034 assert(IS_LEAF(mp));
5035 leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
5037 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
5038 mdb_xcursor_init1(mc, leaf);
5041 if ((rc = mdb_node_read(mc->mc_txn, leaf, data)) != MDB_SUCCESS)
5044 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
5045 rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);
5046 if (rc != MDB_SUCCESS)
5051 MDB_GET_KEY(leaf, key);
5055 /** Move the cursor to the previous data item. */
5057 mdb_cursor_prev(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op)
5063 assert(mc->mc_flags & C_INITIALIZED);
5065 mp = mc->mc_pg[mc->mc_top];
5067 if (mc->mc_db->md_flags & MDB_DUPSORT) {
5068 leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
5069 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
5070 if (op == MDB_PREV || op == MDB_PREV_DUP) {
5071 rc = mdb_cursor_prev(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_PREV);
5072 if (op != MDB_PREV || rc != MDB_NOTFOUND) {
5073 if (rc == MDB_SUCCESS)
5074 MDB_GET_KEY(leaf, key);
5078 mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
5079 if (op == MDB_PREV_DUP)
5080 return MDB_NOTFOUND;
5085 DPRINTF(("cursor_prev: top page is %"Z"u in cursor %p", mp->mp_pgno, (void *) mc));
5087 if (mc->mc_ki[mc->mc_top] == 0) {
5088 DPUTS("=====> move to prev sibling page");
5089 if ((rc = mdb_cursor_sibling(mc, 0)) != MDB_SUCCESS) {
5092 mp = mc->mc_pg[mc->mc_top];
5093 mc->mc_ki[mc->mc_top] = NUMKEYS(mp) - 1;
5094 DPRINTF(("prev page is %"Z"u, key index %u", mp->mp_pgno, mc->mc_ki[mc->mc_top]));
5096 mc->mc_ki[mc->mc_top]--;
5098 mc->mc_flags &= ~C_EOF;
5100 DPRINTF(("==> cursor points to page %"Z"u with %u keys, key index %u",
5101 mp->mp_pgno, NUMKEYS(mp), mc->mc_ki[mc->mc_top]));
5104 key->mv_size = mc->mc_db->md_pad;
5105 key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
5109 assert(IS_LEAF(mp));
5110 leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
5112 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
5113 mdb_xcursor_init1(mc, leaf);
5116 if ((rc = mdb_node_read(mc->mc_txn, leaf, data)) != MDB_SUCCESS)
5119 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
5120 rc = mdb_cursor_last(&mc->mc_xcursor->mx_cursor, data, NULL);
5121 if (rc != MDB_SUCCESS)
5126 MDB_GET_KEY(leaf, key);
5130 /** Set the cursor on a specific data item. */
5132 mdb_cursor_set(MDB_cursor *mc, MDB_val *key, MDB_val *data,
5133 MDB_cursor_op op, int *exactp)
5137 MDB_node *leaf = NULL;
5142 assert(key->mv_size > 0);
5145 mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
5147 /* See if we're already on the right page */
5148 if (mc->mc_flags & C_INITIALIZED) {
5151 mp = mc->mc_pg[mc->mc_top];
5153 mc->mc_ki[mc->mc_top] = 0;
5154 return MDB_NOTFOUND;
5156 if (mp->mp_flags & P_LEAF2) {
5157 nodekey.mv_size = mc->mc_db->md_pad;
5158 nodekey.mv_data = LEAF2KEY(mp, 0, nodekey.mv_size);
5160 leaf = NODEPTR(mp, 0);
5161 MDB_GET_KEY2(leaf, nodekey);
5163 rc = mc->mc_dbx->md_cmp(key, &nodekey);
5165 /* Probably happens rarely, but first node on the page
5166 * was the one we wanted.
5168 mc->mc_ki[mc->mc_top] = 0;
5175 unsigned int nkeys = NUMKEYS(mp);
5177 if (mp->mp_flags & P_LEAF2) {
5178 nodekey.mv_data = LEAF2KEY(mp,
5179 nkeys-1, nodekey.mv_size);
5181 leaf = NODEPTR(mp, nkeys-1);
5182 MDB_GET_KEY2(leaf, nodekey);
5184 rc = mc->mc_dbx->md_cmp(key, &nodekey);
5186 /* last node was the one we wanted */
5187 mc->mc_ki[mc->mc_top] = nkeys-1;
5193 if (mc->mc_ki[mc->mc_top] < NUMKEYS(mp)) {
5194 /* This is definitely the right page, skip search_page */
5195 if (mp->mp_flags & P_LEAF2) {
5196 nodekey.mv_data = LEAF2KEY(mp,
5197 mc->mc_ki[mc->mc_top], nodekey.mv_size);
5199 leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
5200 MDB_GET_KEY2(leaf, nodekey);
5202 rc = mc->mc_dbx->md_cmp(key, &nodekey);
5204 /* current node was the one we wanted */
5214 /* If any parents have right-sibs, search.
5215 * Otherwise, there's nothing further.
5217 for (i=0; i<mc->mc_top; i++)
5219 NUMKEYS(mc->mc_pg[i])-1)
5221 if (i == mc->mc_top) {
5222 /* There are no other pages */
5223 mc->mc_ki[mc->mc_top] = nkeys;
5224 return MDB_NOTFOUND;
5228 /* There are no other pages */
5229 mc->mc_ki[mc->mc_top] = 0;
5230 if (op == MDB_SET_RANGE)
5233 return MDB_NOTFOUND;
5237 rc = mdb_page_search(mc, key, 0);
5238 if (rc != MDB_SUCCESS)
5241 mp = mc->mc_pg[mc->mc_top];
5242 assert(IS_LEAF(mp));
5245 leaf = mdb_node_search(mc, key, exactp);
5246 if (exactp != NULL && !*exactp) {
5247 /* MDB_SET specified and not an exact match. */
5248 return MDB_NOTFOUND;
5252 DPUTS("===> inexact leaf not found, goto sibling");
5253 if ((rc = mdb_cursor_sibling(mc, 1)) != MDB_SUCCESS)
5254 return rc; /* no entries matched */
5255 mp = mc->mc_pg[mc->mc_top];
5256 assert(IS_LEAF(mp));
5257 leaf = NODEPTR(mp, 0);
5261 mc->mc_flags |= C_INITIALIZED;
5262 mc->mc_flags &= ~C_EOF;
5265 key->mv_size = mc->mc_db->md_pad;
5266 key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
5270 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
5271 mdb_xcursor_init1(mc, leaf);
5274 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
5275 if (op == MDB_SET || op == MDB_SET_KEY || op == MDB_SET_RANGE) {
5276 rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);
5279 if (op == MDB_GET_BOTH) {
5285 rc = mdb_cursor_set(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_SET_RANGE, ex2p);
5286 if (rc != MDB_SUCCESS)
5289 } else if (op == MDB_GET_BOTH || op == MDB_GET_BOTH_RANGE) {
5291 if ((rc = mdb_node_read(mc->mc_txn, leaf, &d2)) != MDB_SUCCESS)
5293 rc = mc->mc_dbx->md_dcmp(data, &d2);
5295 if (op == MDB_GET_BOTH || rc > 0)
5296 return MDB_NOTFOUND;
5301 mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
5302 if ((rc = mdb_node_read(mc->mc_txn, leaf, data)) != MDB_SUCCESS)
5307 /* The key already matches in all other cases */
5308 if (op == MDB_SET_RANGE || op == MDB_SET_KEY)
5309 MDB_GET_KEY(leaf, key);
5310 DPRINTF(("==> cursor placed on key [%s]", DKEY(key)));
5315 /** Move the cursor to the first item in the database. */
5317 mdb_cursor_first(MDB_cursor *mc, MDB_val *key, MDB_val *data)
5323 mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
5325 if (!(mc->mc_flags & C_INITIALIZED) || mc->mc_top) {
5326 rc = mdb_page_search(mc, NULL, 0);
5327 if (rc != MDB_SUCCESS)
5330 assert(IS_LEAF(mc->mc_pg[mc->mc_top]));
5332 leaf = NODEPTR(mc->mc_pg[mc->mc_top], 0);
5333 mc->mc_flags |= C_INITIALIZED;
5334 mc->mc_flags &= ~C_EOF;
5336 mc->mc_ki[mc->mc_top] = 0;
5338 if (IS_LEAF2(mc->mc_pg[mc->mc_top])) {
5339 key->mv_size = mc->mc_db->md_pad;
5340 key->mv_data = LEAF2KEY(mc->mc_pg[mc->mc_top], 0, key->mv_size);
5345 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
5346 mdb_xcursor_init1(mc, leaf);
5347 rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);
5351 if ((rc = mdb_node_read(mc->mc_txn, leaf, data)) != MDB_SUCCESS)
5355 MDB_GET_KEY(leaf, key);
5359 /** Move the cursor to the last item in the database. */
5361 mdb_cursor_last(MDB_cursor *mc, MDB_val *key, MDB_val *data)
5367 mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
5369 if (!(mc->mc_flags & C_EOF)) {
5371 if (!(mc->mc_flags & C_INITIALIZED) || mc->mc_top) {
5374 lkey.mv_size = MDB_MAXKEYSIZE+1;
5375 lkey.mv_data = NULL;
5376 rc = mdb_page_search(mc, &lkey, 0);
5377 if (rc != MDB_SUCCESS)
5380 assert(IS_LEAF(mc->mc_pg[mc->mc_top]));
5383 mc->mc_ki[mc->mc_top] = NUMKEYS(mc->mc_pg[mc->mc_top]) - 1;
5384 mc->mc_flags |= C_INITIALIZED|C_EOF;
5385 leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
5387 if (IS_LEAF2(mc->mc_pg[mc->mc_top])) {
5388 key->mv_size = mc->mc_db->md_pad;
5389 key->mv_data = LEAF2KEY(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], key->mv_size);
5394 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
5395 mdb_xcursor_init1(mc, leaf);
5396 rc = mdb_cursor_last(&mc->mc_xcursor->mx_cursor, data, NULL);
5400 if ((rc = mdb_node_read(mc->mc_txn, leaf, data)) != MDB_SUCCESS)
5405 MDB_GET_KEY(leaf, key);
5410 mdb_cursor_get(MDB_cursor *mc, MDB_val *key, MDB_val *data,
5415 int (*mfunc)(MDB_cursor *mc, MDB_val *key, MDB_val *data);
5419 if (mc->mc_txn->mt_flags & MDB_TXN_ERROR)
5423 case MDB_GET_CURRENT:
5424 if (!(mc->mc_flags & C_INITIALIZED)) {
5427 MDB_page *mp = mc->mc_pg[mc->mc_top];
5429 mc->mc_ki[mc->mc_top] = 0;
5435 key->mv_size = mc->mc_db->md_pad;
5436 key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
5438 MDB_node *leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
5439 MDB_GET_KEY(leaf, key);
5441 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
5442 if (mc->mc_flags & C_DEL)
5443 mdb_xcursor_init1(mc, leaf);
5444 rc = mdb_cursor_get(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_GET_CURRENT);
5446 rc = mdb_node_read(mc->mc_txn, leaf, data);
5453 case MDB_GET_BOTH_RANGE:
5458 if (mc->mc_xcursor == NULL) {
5459 rc = MDB_INCOMPATIBLE;
5468 } else if (key->mv_size == 0 || key->mv_size > MDB_MAXKEYSIZE) {
5469 rc = MDB_BAD_VALSIZE;
5470 } else if (op == MDB_SET_RANGE)
5471 rc = mdb_cursor_set(mc, key, data, op, NULL);
5473 rc = mdb_cursor_set(mc, key, data, op, &exact);
5475 case MDB_GET_MULTIPLE:
5476 if (data == NULL || !(mc->mc_flags & C_INITIALIZED)) {
5480 if (!(mc->mc_db->md_flags & MDB_DUPFIXED)) {
5481 rc = MDB_INCOMPATIBLE;
5485 if (!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) ||
5486 (mc->mc_xcursor->mx_cursor.mc_flags & C_EOF))
5489 case MDB_NEXT_MULTIPLE:
5494 if (!(mc->mc_db->md_flags & MDB_DUPFIXED)) {
5495 rc = MDB_INCOMPATIBLE;
5498 if (!(mc->mc_flags & C_INITIALIZED))
5499 rc = mdb_cursor_first(mc, key, data);
5501 rc = mdb_cursor_next(mc, key, data, MDB_NEXT_DUP);
5502 if (rc == MDB_SUCCESS) {
5503 if (mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) {
5506 mx = &mc->mc_xcursor->mx_cursor;
5507 data->mv_size = NUMKEYS(mx->mc_pg[mx->mc_top]) *
5509 data->mv_data = METADATA(mx->mc_pg[mx->mc_top]);
5510 mx->mc_ki[mx->mc_top] = NUMKEYS(mx->mc_pg[mx->mc_top])-1;
5518 case MDB_NEXT_NODUP:
5519 if (!(mc->mc_flags & C_INITIALIZED))
5520 rc = mdb_cursor_first(mc, key, data);
5522 rc = mdb_cursor_next(mc, key, data, op);
5526 case MDB_PREV_NODUP:
5527 if (!(mc->mc_flags & C_INITIALIZED)) {
5528 rc = mdb_cursor_last(mc, key, data);
5531 mc->mc_flags |= C_INITIALIZED;
5532 mc->mc_ki[mc->mc_top]++;
5534 rc = mdb_cursor_prev(mc, key, data, op);
5537 rc = mdb_cursor_first(mc, key, data);
5540 mfunc = mdb_cursor_first;
5542 if (data == NULL || !(mc->mc_flags & C_INITIALIZED)) {
5546 if (mc->mc_xcursor == NULL) {
5547 rc = MDB_INCOMPATIBLE;
5550 if (!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED)) {
5554 rc = mfunc(&mc->mc_xcursor->mx_cursor, data, NULL);
5557 rc = mdb_cursor_last(mc, key, data);
5560 mfunc = mdb_cursor_last;
5563 DPRINTF(("unhandled/unimplemented cursor operation %u", op));
5568 if (mc->mc_flags & C_DEL)
5569 mc->mc_flags ^= C_DEL;
5574 /** Touch all the pages in the cursor stack.
5575 * Makes sure all the pages are writable, before attempting a write operation.
5576 * @param[in] mc The cursor to operate on.
5579 mdb_cursor_touch(MDB_cursor *mc)
5583 if (mc->mc_dbi > MAIN_DBI && !(*mc->mc_dbflag & DB_DIRTY)) {
5586 mdb_cursor_init(&mc2, mc->mc_txn, MAIN_DBI, &mcx);
5587 rc = mdb_page_search(&mc2, &mc->mc_dbx->md_name, MDB_PS_MODIFY);
5590 *mc->mc_dbflag |= DB_DIRTY;
5592 for (mc->mc_top = 0; mc->mc_top < mc->mc_snum; mc->mc_top++) {
5593 rc = mdb_page_touch(mc);
5597 mc->mc_top = mc->mc_snum-1;
5601 /** Do not spill pages to disk if txn is getting full, may fail instead */
5602 #define MDB_NOSPILL 0x8000
5605 mdb_cursor_put(MDB_cursor *mc, MDB_val *key, MDB_val *data,
5608 enum { MDB_NO_ROOT = MDB_LAST_ERRCODE+10 }; /* internal code */
5609 MDB_node *leaf = NULL;
5610 MDB_val xdata, *rdata, dkey;
5613 int do_sub = 0, insert = 0;
5614 unsigned int mcount = 0, dcount = 0, nospill;
5618 char dbuf[MDB_MAXKEYSIZE+1];
5619 unsigned int nflags;
5622 /* Check this first so counter will always be zero on any
5625 if (flags & MDB_MULTIPLE) {
5626 dcount = data[1].mv_size;
5627 data[1].mv_size = 0;
5628 if (!F_ISSET(mc->mc_db->md_flags, MDB_DUPFIXED))
5629 return MDB_INCOMPATIBLE;
5632 nospill = flags & MDB_NOSPILL;
5633 flags &= ~MDB_NOSPILL;
5635 if (mc->mc_txn->mt_flags & (MDB_TXN_RDONLY|MDB_TXN_ERROR))
5636 return (mc->mc_txn->mt_flags & MDB_TXN_RDONLY) ? EACCES : MDB_BAD_TXN;
5638 if (flags != MDB_CURRENT && (key->mv_size == 0 || key->mv_size > MDB_MAXKEYSIZE))
5639 return MDB_BAD_VALSIZE;
5641 if (F_ISSET(mc->mc_db->md_flags, MDB_DUPSORT) && data->mv_size > MDB_MAXKEYSIZE)
5642 return MDB_BAD_VALSIZE;
5644 #if SIZE_MAX > MAXDATASIZE
5645 if (data->mv_size > MAXDATASIZE)
5646 return MDB_BAD_VALSIZE;
5649 DPRINTF(("==> put db %u key [%s], size %"Z"u, data size %"Z"u",
5650 mc->mc_dbi, DKEY(key), key ? key->mv_size:0, data->mv_size));
5654 if (flags == MDB_CURRENT) {
5655 if (!(mc->mc_flags & C_INITIALIZED))
5658 } else if (mc->mc_db->md_root == P_INVALID) {
5659 /* new database, cursor has nothing to point to */
5661 mc->mc_flags &= ~C_INITIALIZED;
5666 if (flags & MDB_APPEND) {
5668 rc = mdb_cursor_last(mc, &k2, &d2);
5670 rc = mc->mc_dbx->md_cmp(key, &k2);
5673 mc->mc_ki[mc->mc_top]++;
5675 /* new key is <= last key */
5680 rc = mdb_cursor_set(mc, key, &d2, MDB_SET, &exact);
5682 if ((flags & MDB_NOOVERWRITE) && rc == 0) {
5683 DPRINTF(("duplicate key [%s]", DKEY(key)));
5685 return MDB_KEYEXIST;
5687 if (rc && rc != MDB_NOTFOUND)
5691 if (mc->mc_flags & C_DEL)
5692 mc->mc_flags ^= C_DEL;
5694 /* Cursor is positioned, check for room in the dirty list */
5696 if (flags & MDB_MULTIPLE) {
5698 xdata.mv_size = data->mv_size * dcount;
5702 if ((rc2 = mdb_page_spill(mc, key, rdata)))
5706 if (rc == MDB_NO_ROOT) {
5708 /* new database, write a root leaf page */
5709 DPUTS("allocating new root leaf page");
5710 if ((rc2 = mdb_page_new(mc, P_LEAF, 1, &np))) {
5713 mdb_cursor_push(mc, np);
5714 mc->mc_db->md_root = np->mp_pgno;
5715 mc->mc_db->md_depth++;
5716 *mc->mc_dbflag |= DB_DIRTY;
5717 if ((mc->mc_db->md_flags & (MDB_DUPSORT|MDB_DUPFIXED))
5719 np->mp_flags |= P_LEAF2;
5720 mc->mc_flags |= C_INITIALIZED;
5722 /* make sure all cursor pages are writable */
5723 rc2 = mdb_cursor_touch(mc);
5728 /* The key already exists */
5729 if (rc == MDB_SUCCESS) {
5730 /* there's only a key anyway, so this is a no-op */
5731 if (IS_LEAF2(mc->mc_pg[mc->mc_top])) {
5732 unsigned int ksize = mc->mc_db->md_pad;
5733 if (key->mv_size != ksize)
5734 return MDB_BAD_VALSIZE;
5735 if (flags == MDB_CURRENT) {
5736 char *ptr = LEAF2KEY(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], ksize);
5737 memcpy(ptr, key->mv_data, ksize);
5742 leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
5745 if (F_ISSET(mc->mc_db->md_flags, MDB_DUPSORT)) {
5746 /* Was a single item before, must convert now */
5748 if (!F_ISSET(leaf->mn_flags, F_DUPDATA)) {
5749 /* Just overwrite the current item */
5750 if (flags == MDB_CURRENT)
5753 dkey.mv_size = NODEDSZ(leaf);
5754 dkey.mv_data = NODEDATA(leaf);
5755 #if UINT_MAX < SIZE_MAX
5756 if (mc->mc_dbx->md_dcmp == mdb_cmp_int && dkey.mv_size == sizeof(size_t))
5757 #ifdef MISALIGNED_OK
5758 mc->mc_dbx->md_dcmp = mdb_cmp_long;
5760 mc->mc_dbx->md_dcmp = mdb_cmp_cint;
5763 /* if data matches, skip it */
5764 if (!mc->mc_dbx->md_dcmp(data, &dkey)) {
5765 if (flags & MDB_NODUPDATA)
5767 else if (flags & MDB_MULTIPLE)
5774 /* create a fake page for the dup items */
5775 memcpy(dbuf, dkey.mv_data, dkey.mv_size);
5776 dkey.mv_data = dbuf;
5777 fp = (MDB_page *)&pbuf;
5778 fp->mp_pgno = mc->mc_pg[mc->mc_top]->mp_pgno;
5779 fp->mp_flags = P_LEAF|P_DIRTY|P_SUBP;
5780 fp->mp_lower = PAGEHDRSZ;
5781 fp->mp_upper = PAGEHDRSZ + dkey.mv_size + data->mv_size;
5782 if (mc->mc_db->md_flags & MDB_DUPFIXED) {
5783 fp->mp_flags |= P_LEAF2;
5784 fp->mp_pad = data->mv_size;
5785 fp->mp_upper += 2 * data->mv_size; /* leave space for 2 more */
5787 fp->mp_upper += 2 * sizeof(indx_t) + 2 * NODESIZE +
5788 (dkey.mv_size & 1) + (data->mv_size & 1);
5790 mdb_node_del(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], 0);
5793 xdata.mv_size = fp->mp_upper;
5798 if (!F_ISSET(leaf->mn_flags, F_SUBDATA)) {
5799 /* See if we need to convert from fake page to subDB */
5801 unsigned int offset;
5805 fp = NODEDATA(leaf);
5806 if (flags == MDB_CURRENT) {
5808 fp->mp_flags |= P_DIRTY;
5809 COPY_PGNO(fp->mp_pgno, mc->mc_pg[mc->mc_top]->mp_pgno);
5810 mc->mc_xcursor->mx_cursor.mc_pg[0] = fp;
5814 if (mc->mc_db->md_flags & MDB_DUPFIXED) {
5815 offset = fp->mp_pad;
5816 if (SIZELEFT(fp) >= offset)
5818 offset *= 4; /* space for 4 more */
5820 offset = NODESIZE + sizeof(indx_t) + data->mv_size;
5822 offset += offset & 1;
5823 fp_flags = fp->mp_flags;
5824 if (NODESIZE + sizeof(indx_t) + NODEKSZ(leaf) + NODEDSZ(leaf) +
5825 offset >= mc->mc_txn->mt_env->me_nodemax) {
5826 /* yes, convert it */
5828 if (mc->mc_db->md_flags & MDB_DUPFIXED) {
5829 dummy.md_pad = fp->mp_pad;
5830 dummy.md_flags = MDB_DUPFIXED;
5831 if (mc->mc_db->md_flags & MDB_INTEGERDUP)
5832 dummy.md_flags |= MDB_INTEGERKEY;
5835 dummy.md_branch_pages = 0;
5836 dummy.md_leaf_pages = 1;
5837 dummy.md_overflow_pages = 0;
5838 dummy.md_entries = NUMKEYS(fp);
5840 xdata.mv_size = sizeof(MDB_db);
5841 xdata.mv_data = &dummy;
5842 if ((rc = mdb_page_alloc(mc, 1, &mp)))
5844 offset = mc->mc_txn->mt_env->me_psize - NODEDSZ(leaf);
5845 flags |= F_DUPDATA|F_SUBDATA;
5846 dummy.md_root = mp->mp_pgno;
5847 fp_flags &= ~P_SUBP;
5849 /* no, just grow it */
5851 xdata.mv_size = NODEDSZ(leaf) + offset;
5852 xdata.mv_data = &pbuf;
5853 mp = (MDB_page *)&pbuf;
5854 mp->mp_pgno = mc->mc_pg[mc->mc_top]->mp_pgno;
5857 mp->mp_flags = fp_flags | P_DIRTY;
5858 mp->mp_pad = fp->mp_pad;
5859 mp->mp_lower = fp->mp_lower;
5860 mp->mp_upper = fp->mp_upper + offset;
5862 memcpy(METADATA(mp), METADATA(fp), NUMKEYS(fp) * fp->mp_pad);
5864 nsize = NODEDSZ(leaf) - fp->mp_upper;
5865 memcpy((char *)mp + mp->mp_upper, (char *)fp + fp->mp_upper, nsize);
5866 for (i=0; i<NUMKEYS(fp); i++)
5867 mp->mp_ptrs[i] = fp->mp_ptrs[i] + offset;
5869 mdb_node_del(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], 0);
5873 /* data is on sub-DB, just store it */
5874 flags |= F_DUPDATA|F_SUBDATA;
5878 /* overflow page overwrites need special handling */
5879 if (F_ISSET(leaf->mn_flags, F_BIGDATA)) {
5882 unsigned psize = mc->mc_txn->mt_env->me_psize;
5883 int level, ovpages, dpages = OVPAGES(data->mv_size, psize);
5885 memcpy(&pg, NODEDATA(leaf), sizeof(pg));
5886 if ((rc2 = mdb_page_get(mc->mc_txn, pg, &omp, &level)) != 0)
5888 ovpages = omp->mp_pages;
5890 /* Is the ov page large enough? */
5891 if (ovpages >= dpages) {
5892 if (!(omp->mp_flags & P_DIRTY) &&
5893 (level || (mc->mc_txn->mt_env->me_flags & MDB_WRITEMAP)))
5895 rc = mdb_page_unspill(mc->mc_txn, omp, &omp);
5898 level = 0; /* dirty in this txn or clean */
5901 if (omp->mp_flags & P_DIRTY) {
5902 /* yes, overwrite it. Note in this case we don't
5903 * bother to try shrinking the page if the new data
5904 * is smaller than the overflow threshold.
5907 /* It is writable only in a parent txn */
5908 size_t sz = (size_t) psize * ovpages, off;
5909 MDB_page *np = mdb_page_malloc(mc->mc_txn, ovpages);
5915 mdb_mid2l_insert(mc->mc_txn->mt_u.dirty_list, &id2);
5916 if (!(flags & MDB_RESERVE)) {
5917 /* Copy end of page, adjusting alignment so
5918 * compiler may copy words instead of bytes.
5920 off = (PAGEHDRSZ + data->mv_size) & -sizeof(size_t);
5921 memcpy((size_t *)((char *)np + off),
5922 (size_t *)((char *)omp + off), sz - off);
5925 memcpy(np, omp, sz); /* Copy beginning of page */
5928 SETDSZ(leaf, data->mv_size);
5929 if (F_ISSET(flags, MDB_RESERVE))
5930 data->mv_data = METADATA(omp);
5932 memcpy(METADATA(omp), data->mv_data, data->mv_size);
5936 if ((rc2 = mdb_ovpage_free(mc, omp)) != MDB_SUCCESS)
5938 } else if (NODEDSZ(leaf) == data->mv_size) {
5939 /* same size, just replace it. Note that we could
5940 * also reuse this node if the new data is smaller,
5941 * but instead we opt to shrink the node in that case.
5943 if (F_ISSET(flags, MDB_RESERVE))
5944 data->mv_data = NODEDATA(leaf);
5945 else if (data->mv_size)
5946 memcpy(NODEDATA(leaf), data->mv_data, data->mv_size);
5948 memcpy(NODEKEY(leaf), key->mv_data, key->mv_size);
5951 mdb_node_del(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], 0);
5952 mc->mc_db->md_entries--;
5954 DPRINTF(("inserting key at index %i", mc->mc_ki[mc->mc_top]));
5961 nflags = flags & NODE_ADD_FLAGS;
5962 nsize = IS_LEAF2(mc->mc_pg[mc->mc_top]) ? key->mv_size : mdb_leaf_size(mc->mc_txn->mt_env, key, rdata);
5963 if (SIZELEFT(mc->mc_pg[mc->mc_top]) < nsize) {
5964 if (( flags & (F_DUPDATA|F_SUBDATA)) == F_DUPDATA )
5965 nflags &= ~MDB_APPEND;
5967 nflags |= MDB_SPLIT_REPLACE;
5968 rc = mdb_page_split(mc, key, rdata, P_INVALID, nflags);
5970 /* There is room already in this leaf page. */
5971 rc = mdb_node_add(mc, mc->mc_ki[mc->mc_top], key, rdata, 0, nflags);
5972 if (rc == 0 && !do_sub && insert) {
5973 /* Adjust other cursors pointing to mp */
5974 MDB_cursor *m2, *m3;
5975 MDB_dbi dbi = mc->mc_dbi;
5976 unsigned i = mc->mc_top;
5977 MDB_page *mp = mc->mc_pg[i];
5979 if (mc->mc_flags & C_SUB)
5982 for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
5983 if (mc->mc_flags & C_SUB)
5984 m3 = &m2->mc_xcursor->mx_cursor;
5987 if (m3 == mc || m3->mc_snum < mc->mc_snum) continue;
5988 if (m3->mc_pg[i] == mp && m3->mc_ki[i] >= mc->mc_ki[i]) {
5995 if (rc != MDB_SUCCESS)
5996 mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
5998 /* Now store the actual data in the child DB. Note that we're
5999 * storing the user data in the keys field, so there are strict
6000 * size limits on dupdata. The actual data fields of the child
6001 * DB are all zero size.
6008 leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
6009 if (flags & MDB_CURRENT) {
6010 xflags = MDB_CURRENT|MDB_NOSPILL;
6012 mdb_xcursor_init1(mc, leaf);
6013 xflags = (flags & MDB_NODUPDATA) ?
6014 MDB_NOOVERWRITE|MDB_NOSPILL : MDB_NOSPILL;
6016 /* converted, write the original data first */
6018 rc = mdb_cursor_put(&mc->mc_xcursor->mx_cursor, &dkey, &xdata, xflags);
6022 /* Adjust other cursors pointing to mp */
6024 unsigned i = mc->mc_top;
6025 MDB_page *mp = mc->mc_pg[i];
6027 for (m2 = mc->mc_txn->mt_cursors[mc->mc_dbi]; m2; m2=m2->mc_next) {
6028 if (m2 == mc || m2->mc_snum < mc->mc_snum) continue;
6029 if (!(m2->mc_flags & C_INITIALIZED)) continue;
6030 if (m2->mc_pg[i] == mp && m2->mc_ki[i] == mc->mc_ki[i]) {
6031 mdb_xcursor_init1(m2, leaf);
6035 /* we've done our job */
6038 if (flags & MDB_APPENDDUP)
6039 xflags |= MDB_APPEND;
6040 rc = mdb_cursor_put(&mc->mc_xcursor->mx_cursor, data, &xdata, xflags);
6041 if (flags & F_SUBDATA) {
6042 void *db = NODEDATA(leaf);
6043 memcpy(db, &mc->mc_xcursor->mx_db, sizeof(MDB_db));
6046 /* sub-writes might have failed so check rc again.
6047 * Don't increment count if we just replaced an existing item.
6049 if (!rc && !(flags & MDB_CURRENT))
6050 mc->mc_db->md_entries++;
6051 if (flags & MDB_MULTIPLE) {
6055 /* let caller know how many succeeded, if any */
6056 data[1].mv_size = mcount;
6057 if (mcount < dcount) {
6058 data[0].mv_data = (char *)data[0].mv_data + data[0].mv_size;
6059 leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
6066 /* If we succeeded and the key didn't exist before, make sure
6067 * the cursor is marked valid.
6070 mc->mc_flags |= C_INITIALIZED;
6075 mdb_cursor_del(MDB_cursor *mc, unsigned int flags)
6080 if (mc->mc_txn->mt_flags & (MDB_TXN_RDONLY|MDB_TXN_ERROR))
6081 return (mc->mc_txn->mt_flags & MDB_TXN_RDONLY) ? EACCES : MDB_BAD_TXN;
6083 if (!(mc->mc_flags & C_INITIALIZED))
6086 if (!(flags & MDB_NOSPILL) && (rc = mdb_page_spill(mc, NULL, NULL)))
6088 flags &= ~MDB_NOSPILL; /* TODO: Or change (flags != MDB_NODUPDATA) to ~(flags & MDB_NODUPDATA), not looking at the logic of that code just now */
6090 rc = mdb_cursor_touch(mc);
6094 leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
6096 if (!IS_LEAF2(mc->mc_pg[mc->mc_top]) && F_ISSET(leaf->mn_flags, F_DUPDATA)) {
6097 if (!(flags & MDB_NODUPDATA)) {
6098 if (!F_ISSET(leaf->mn_flags, F_SUBDATA)) {
6099 mc->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(leaf);
6101 rc = mdb_cursor_del(&mc->mc_xcursor->mx_cursor, MDB_NOSPILL);
6102 /* If sub-DB still has entries, we're done */
6103 if (mc->mc_xcursor->mx_db.md_entries) {
6104 if (leaf->mn_flags & F_SUBDATA) {
6105 /* update subDB info */
6106 void *db = NODEDATA(leaf);
6107 memcpy(db, &mc->mc_xcursor->mx_db, sizeof(MDB_db));
6110 /* shrink fake page */
6111 mdb_node_shrink(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
6112 leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
6113 mc->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(leaf);
6114 /* fix other sub-DB cursors pointed at this fake page */
6115 for (m2 = mc->mc_txn->mt_cursors[mc->mc_dbi]; m2; m2=m2->mc_next) {
6116 if (m2 == mc || m2->mc_snum < mc->mc_snum) continue;
6117 if (m2->mc_pg[mc->mc_top] == mc->mc_pg[mc->mc_top] &&
6118 m2->mc_ki[mc->mc_top] == mc->mc_ki[mc->mc_top])
6119 m2->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(leaf);
6122 mc->mc_db->md_entries--;
6123 mc->mc_flags |= C_DEL;
6126 /* otherwise fall thru and delete the sub-DB */
6129 if (leaf->mn_flags & F_SUBDATA) {
6130 /* add all the child DB's pages to the free list */
6131 rc = mdb_drop0(&mc->mc_xcursor->mx_cursor, 0);
6132 if (rc == MDB_SUCCESS) {
6133 mc->mc_db->md_entries -=
6134 mc->mc_xcursor->mx_db.md_entries;
6139 return mdb_cursor_del0(mc, leaf);
6142 /** Allocate and initialize new pages for a database.
6143 * @param[in] mc a cursor on the database being added to.
6144 * @param[in] flags flags defining what type of page is being allocated.
6145 * @param[in] num the number of pages to allocate. This is usually 1,
6146 * unless allocating overflow pages for a large record.
6147 * @param[out] mp Address of a page, or NULL on failure.
6148 * @return 0 on success, non-zero on failure.
6151 mdb_page_new(MDB_cursor *mc, uint32_t flags, int num, MDB_page **mp)
6156 if ((rc = mdb_page_alloc(mc, num, &np)))
6158 DPRINTF(("allocated new mpage %"Z"u, page size %u",
6159 np->mp_pgno, mc->mc_txn->mt_env->me_psize));
6160 np->mp_flags = flags | P_DIRTY;
6161 np->mp_lower = PAGEHDRSZ;
6162 np->mp_upper = mc->mc_txn->mt_env->me_psize;
6165 mc->mc_db->md_branch_pages++;
6166 else if (IS_LEAF(np))
6167 mc->mc_db->md_leaf_pages++;
6168 else if (IS_OVERFLOW(np)) {
6169 mc->mc_db->md_overflow_pages += num;
6177 /** Calculate the size of a leaf node.
6178 * The size depends on the environment's page size; if a data item
6179 * is too large it will be put onto an overflow page and the node
6180 * size will only include the key and not the data. Sizes are always
6181 * rounded up to an even number of bytes, to guarantee 2-byte alignment
6182 * of the #MDB_node headers.
6183 * @param[in] env The environment handle.
6184 * @param[in] key The key for the node.
6185 * @param[in] data The data for the node.
6186 * @return The number of bytes needed to store the node.
6189 mdb_leaf_size(MDB_env *env, MDB_val *key, MDB_val *data)
6193 sz = LEAFSIZE(key, data);
6194 if (sz >= env->me_nodemax) {
6195 /* put on overflow page */
6196 sz -= data->mv_size - sizeof(pgno_t);
6200 return sz + sizeof(indx_t);
6203 /** Calculate the size of a branch node.
6204 * The size should depend on the environment's page size but since
6205 * we currently don't support spilling large keys onto overflow
6206 * pages, it's simply the size of the #MDB_node header plus the
6207 * size of the key. Sizes are always rounded up to an even number
6208 * of bytes, to guarantee 2-byte alignment of the #MDB_node headers.
6209 * @param[in] env The environment handle.
6210 * @param[in] key The key for the node.
6211 * @return The number of bytes needed to store the node.
6214 mdb_branch_size(MDB_env *env, MDB_val *key)
6219 if (sz >= env->me_nodemax) {
6220 /* put on overflow page */
6221 /* not implemented */
6222 /* sz -= key->size - sizeof(pgno_t); */
6225 return sz + sizeof(indx_t);
6228 /** Add a node to the page pointed to by the cursor.
6229 * @param[in] mc The cursor for this operation.
6230 * @param[in] indx The index on the page where the new node should be added.
6231 * @param[in] key The key for the new node.
6232 * @param[in] data The data for the new node, if any.
6233 * @param[in] pgno The page number, if adding a branch node.
6234 * @param[in] flags Flags for the node.
6235 * @return 0 on success, non-zero on failure. Possible errors are:
6237 * <li>ENOMEM - failed to allocate overflow pages for the node.
6238 * <li>MDB_PAGE_FULL - there is insufficient room in the page. This error
6239 * should never happen since all callers already calculate the
6240 * page's free space before calling this function.
6244 mdb_node_add(MDB_cursor *mc, indx_t indx,
6245 MDB_val *key, MDB_val *data, pgno_t pgno, unsigned int flags)
6248 size_t node_size = NODESIZE;
6251 MDB_page *mp = mc->mc_pg[mc->mc_top];
6252 MDB_page *ofp = NULL; /* overflow page */
6255 assert(mp->mp_upper >= mp->mp_lower);
6257 DPRINTF(("add to %s %spage %"Z"u index %i, data size %"Z"u key size %"Z"u [%s]",
6258 IS_LEAF(mp) ? "leaf" : "branch",
6259 IS_SUBP(mp) ? "sub-" : "",
6260 mp->mp_pgno, indx, data ? data->mv_size : 0,
6261 key ? key->mv_size : 0, key ? DKEY(key) : NULL));
6264 /* Move higher keys up one slot. */
6265 int ksize = mc->mc_db->md_pad, dif;
6266 char *ptr = LEAF2KEY(mp, indx, ksize);
6267 dif = NUMKEYS(mp) - indx;
6269 memmove(ptr+ksize, ptr, dif*ksize);
6270 /* insert new key */
6271 memcpy(ptr, key->mv_data, ksize);
6273 /* Just using these for counting */
6274 mp->mp_lower += sizeof(indx_t);
6275 mp->mp_upper -= ksize - sizeof(indx_t);
6280 node_size += key->mv_size;
6284 if (F_ISSET(flags, F_BIGDATA)) {
6285 /* Data already on overflow page. */
6286 node_size += sizeof(pgno_t);
6287 } else if (node_size + data->mv_size >= mc->mc_txn->mt_env->me_nodemax) {
6288 int ovpages = OVPAGES(data->mv_size, mc->mc_txn->mt_env->me_psize);
6290 /* Put data on overflow page. */
6291 DPRINTF(("data size is %"Z"u, node would be %"Z"u, put data on overflow page",
6292 data->mv_size, node_size+data->mv_size));
6293 node_size += sizeof(pgno_t);
6294 if ((rc = mdb_page_new(mc, P_OVERFLOW, ovpages, &ofp)))
6296 DPRINTF(("allocated overflow page %"Z"u", ofp->mp_pgno));
6299 node_size += data->mv_size;
6302 node_size += node_size & 1;
6304 if (node_size + sizeof(indx_t) > SIZELEFT(mp)) {
6305 DPRINTF(("not enough room in page %"Z"u, got %u ptrs",
6306 mp->mp_pgno, NUMKEYS(mp)));
6307 DPRINTF(("upper - lower = %u - %u = %u", mp->mp_upper, mp->mp_lower,
6308 mp->mp_upper - mp->mp_lower));
6309 DPRINTF(("node size = %"Z"u", node_size));
6310 return MDB_PAGE_FULL;
6313 /* Move higher pointers up one slot. */
6314 for (i = NUMKEYS(mp); i > indx; i--)
6315 mp->mp_ptrs[i] = mp->mp_ptrs[i - 1];
6317 /* Adjust free space offsets. */
6318 ofs = mp->mp_upper - node_size;
6319 assert(ofs >= mp->mp_lower + sizeof(indx_t));
6320 mp->mp_ptrs[indx] = ofs;
6322 mp->mp_lower += sizeof(indx_t);
6324 /* Write the node data. */
6325 node = NODEPTR(mp, indx);
6326 node->mn_ksize = (key == NULL) ? 0 : key->mv_size;
6327 node->mn_flags = flags;
6329 SETDSZ(node,data->mv_size);
6334 memcpy(NODEKEY(node), key->mv_data, key->mv_size);
6339 if (F_ISSET(flags, F_BIGDATA))
6340 memcpy(node->mn_data + key->mv_size, data->mv_data,
6342 else if (F_ISSET(flags, MDB_RESERVE))
6343 data->mv_data = node->mn_data + key->mv_size;
6345 memcpy(node->mn_data + key->mv_size, data->mv_data,
6348 memcpy(node->mn_data + key->mv_size, &ofp->mp_pgno,
6350 if (F_ISSET(flags, MDB_RESERVE))
6351 data->mv_data = METADATA(ofp);
6353 memcpy(METADATA(ofp), data->mv_data, data->mv_size);
6360 /** Delete the specified node from a page.
6361 * @param[in] mp The page to operate on.
6362 * @param[in] indx The index of the node to delete.
6363 * @param[in] ksize The size of a node. Only used if the page is
6364 * part of a #MDB_DUPFIXED database.
6367 mdb_node_del(MDB_page *mp, indx_t indx, int ksize)
6370 indx_t i, j, numkeys, ptr;
6377 COPY_PGNO(pgno, mp->mp_pgno);
6378 DPRINTF(("delete node %u on %s page %"Z"u", indx,
6379 IS_LEAF(mp) ? "leaf" : "branch", pgno));
6382 assert(indx < NUMKEYS(mp));
6385 int x = NUMKEYS(mp) - 1 - indx;
6386 base = LEAF2KEY(mp, indx, ksize);
6388 memmove(base, base + ksize, x * ksize);
6389 mp->mp_lower -= sizeof(indx_t);
6390 mp->mp_upper += ksize - sizeof(indx_t);
6394 node = NODEPTR(mp, indx);
6395 sz = NODESIZE + node->mn_ksize;
6397 if (F_ISSET(node->mn_flags, F_BIGDATA))
6398 sz += sizeof(pgno_t);
6400 sz += NODEDSZ(node);
6404 ptr = mp->mp_ptrs[indx];
6405 numkeys = NUMKEYS(mp);
6406 for (i = j = 0; i < numkeys; i++) {
6408 mp->mp_ptrs[j] = mp->mp_ptrs[i];
6409 if (mp->mp_ptrs[i] < ptr)
6410 mp->mp_ptrs[j] += sz;
6415 base = (char *)mp + mp->mp_upper;
6416 memmove(base + sz, base, ptr - mp->mp_upper);
6418 mp->mp_lower -= sizeof(indx_t);
6422 /** Compact the main page after deleting a node on a subpage.
6423 * @param[in] mp The main page to operate on.
6424 * @param[in] indx The index of the subpage on the main page.
6427 mdb_node_shrink(MDB_page *mp, indx_t indx)
6434 indx_t i, numkeys, ptr;
6436 node = NODEPTR(mp, indx);
6437 sp = (MDB_page *)NODEDATA(node);
6438 osize = NODEDSZ(node);
6440 delta = sp->mp_upper - sp->mp_lower;
6441 SETDSZ(node, osize - delta);
6442 xp = (MDB_page *)((char *)sp + delta);
6444 /* shift subpage upward */
6446 nsize = NUMKEYS(sp) * sp->mp_pad;
6447 memmove(METADATA(xp), METADATA(sp), nsize);
6450 nsize = osize - sp->mp_upper;
6451 numkeys = NUMKEYS(sp);
6452 for (i=numkeys-1; i>=0; i--)
6453 xp->mp_ptrs[i] = sp->mp_ptrs[i] - delta;
6455 xp->mp_upper = sp->mp_lower;
6456 xp->mp_lower = sp->mp_lower;
6457 xp->mp_flags = sp->mp_flags;
6458 xp->mp_pad = sp->mp_pad;
6459 COPY_PGNO(xp->mp_pgno, mp->mp_pgno);
6461 /* shift lower nodes upward */
6462 ptr = mp->mp_ptrs[indx];
6463 numkeys = NUMKEYS(mp);
6464 for (i = 0; i < numkeys; i++) {
6465 if (mp->mp_ptrs[i] <= ptr)
6466 mp->mp_ptrs[i] += delta;
6469 base = (char *)mp + mp->mp_upper;
6470 memmove(base + delta, base, ptr - mp->mp_upper + NODESIZE + NODEKSZ(node));
6471 mp->mp_upper += delta;
6474 /** Initial setup of a sorted-dups cursor.
6475 * Sorted duplicates are implemented as a sub-database for the given key.
6476 * The duplicate data items are actually keys of the sub-database.
6477 * Operations on the duplicate data items are performed using a sub-cursor
6478 * initialized when the sub-database is first accessed. This function does
6479 * the preliminary setup of the sub-cursor, filling in the fields that
6480 * depend only on the parent DB.
6481 * @param[in] mc The main cursor whose sorted-dups cursor is to be initialized.
6484 mdb_xcursor_init0(MDB_cursor *mc)
6486 MDB_xcursor *mx = mc->mc_xcursor;
6488 mx->mx_cursor.mc_xcursor = NULL;
6489 mx->mx_cursor.mc_txn = mc->mc_txn;
6490 mx->mx_cursor.mc_db = &mx->mx_db;
6491 mx->mx_cursor.mc_dbx = &mx->mx_dbx;
6492 mx->mx_cursor.mc_dbi = mc->mc_dbi+1;
6493 mx->mx_cursor.mc_dbflag = &mx->mx_dbflag;
6494 mx->mx_cursor.mc_snum = 0;
6495 mx->mx_cursor.mc_top = 0;
6496 mx->mx_cursor.mc_flags = C_SUB;
6497 mx->mx_dbx.md_cmp = mc->mc_dbx->md_dcmp;
6498 mx->mx_dbx.md_dcmp = NULL;
6499 mx->mx_dbx.md_rel = mc->mc_dbx->md_rel;
6502 /** Final setup of a sorted-dups cursor.
6503 * Sets up the fields that depend on the data from the main cursor.
6504 * @param[in] mc The main cursor whose sorted-dups cursor is to be initialized.
6505 * @param[in] node The data containing the #MDB_db record for the
6506 * sorted-dup database.
6509 mdb_xcursor_init1(MDB_cursor *mc, MDB_node *node)
6511 MDB_xcursor *mx = mc->mc_xcursor;
6513 if (node->mn_flags & F_SUBDATA) {
6514 memcpy(&mx->mx_db, NODEDATA(node), sizeof(MDB_db));
6515 mx->mx_cursor.mc_pg[0] = 0;
6516 mx->mx_cursor.mc_snum = 0;
6517 mx->mx_cursor.mc_flags = C_SUB;
6519 MDB_page *fp = NODEDATA(node);
6520 mx->mx_db.md_pad = mc->mc_pg[mc->mc_top]->mp_pad;
6521 mx->mx_db.md_flags = 0;
6522 mx->mx_db.md_depth = 1;
6523 mx->mx_db.md_branch_pages = 0;
6524 mx->mx_db.md_leaf_pages = 1;
6525 mx->mx_db.md_overflow_pages = 0;
6526 mx->mx_db.md_entries = NUMKEYS(fp);
6527 COPY_PGNO(mx->mx_db.md_root, fp->mp_pgno);
6528 mx->mx_cursor.mc_snum = 1;
6529 mx->mx_cursor.mc_flags = C_INITIALIZED|C_SUB;
6530 mx->mx_cursor.mc_top = 0;
6531 mx->mx_cursor.mc_pg[0] = fp;
6532 mx->mx_cursor.mc_ki[0] = 0;
6533 if (mc->mc_db->md_flags & MDB_DUPFIXED) {
6534 mx->mx_db.md_flags = MDB_DUPFIXED;
6535 mx->mx_db.md_pad = fp->mp_pad;
6536 if (mc->mc_db->md_flags & MDB_INTEGERDUP)
6537 mx->mx_db.md_flags |= MDB_INTEGERKEY;
6540 DPRINTF(("Sub-db %u for db %u root page %"Z"u", mx->mx_cursor.mc_dbi, mc->mc_dbi,
6541 mx->mx_db.md_root));
6542 mx->mx_dbflag = DB_VALID | (F_ISSET(mc->mc_pg[mc->mc_top]->mp_flags, P_DIRTY) ?
6544 mx->mx_dbx.md_name.mv_data = NODEKEY(node);
6545 mx->mx_dbx.md_name.mv_size = node->mn_ksize;
6546 #if UINT_MAX < SIZE_MAX
6547 if (mx->mx_dbx.md_cmp == mdb_cmp_int && mx->mx_db.md_pad == sizeof(size_t))
6548 #ifdef MISALIGNED_OK
6549 mx->mx_dbx.md_cmp = mdb_cmp_long;
6551 mx->mx_dbx.md_cmp = mdb_cmp_cint;
6556 /** Initialize a cursor for a given transaction and database. */
6558 mdb_cursor_init(MDB_cursor *mc, MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx)
6561 mc->mc_backup = NULL;
6564 mc->mc_db = &txn->mt_dbs[dbi];
6565 mc->mc_dbx = &txn->mt_dbxs[dbi];
6566 mc->mc_dbflag = &txn->mt_dbflags[dbi];
6571 if (txn->mt_dbs[dbi].md_flags & MDB_DUPSORT) {
6573 mc->mc_xcursor = mx;
6574 mdb_xcursor_init0(mc);
6576 mc->mc_xcursor = NULL;
6578 if (*mc->mc_dbflag & DB_STALE) {
6579 mdb_page_search(mc, NULL, MDB_PS_ROOTONLY);
6584 mdb_cursor_open(MDB_txn *txn, MDB_dbi dbi, MDB_cursor **ret)
6587 size_t size = sizeof(MDB_cursor);
6589 if (txn == NULL || ret == NULL || dbi >= txn->mt_numdbs || !(txn->mt_dbflags[dbi] & DB_VALID))
6592 if (txn->mt_flags & MDB_TXN_ERROR)
6595 /* Allow read access to the freelist */
6596 if (!dbi && !F_ISSET(txn->mt_flags, MDB_TXN_RDONLY))
6599 if (txn->mt_dbs[dbi].md_flags & MDB_DUPSORT)
6600 size += sizeof(MDB_xcursor);
6602 if ((mc = malloc(size)) != NULL) {
6603 mdb_cursor_init(mc, txn, dbi, (MDB_xcursor *)(mc + 1));
6604 if (txn->mt_cursors) {
6605 mc->mc_next = txn->mt_cursors[dbi];
6606 txn->mt_cursors[dbi] = mc;
6607 mc->mc_flags |= C_UNTRACK;
6619 mdb_cursor_renew(MDB_txn *txn, MDB_cursor *mc)
6621 if (txn == NULL || mc == NULL || mc->mc_dbi >= txn->mt_numdbs)
6624 if ((mc->mc_flags & C_UNTRACK) || txn->mt_cursors)
6627 mdb_cursor_init(mc, txn, mc->mc_dbi, mc->mc_xcursor);
6631 /* Return the count of duplicate data items for the current key */
6633 mdb_cursor_count(MDB_cursor *mc, size_t *countp)
6637 if (mc == NULL || countp == NULL)
6640 if (mc->mc_xcursor == NULL)
6641 return MDB_INCOMPATIBLE;
6643 leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
6644 if (!F_ISSET(leaf->mn_flags, F_DUPDATA)) {
6647 if (!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED))
6650 *countp = mc->mc_xcursor->mx_db.md_entries;
6656 mdb_cursor_close(MDB_cursor *mc)
6658 if (mc && !mc->mc_backup) {
6659 /* remove from txn, if tracked */
6660 if ((mc->mc_flags & C_UNTRACK) && mc->mc_txn->mt_cursors) {
6661 MDB_cursor **prev = &mc->mc_txn->mt_cursors[mc->mc_dbi];
6662 while (*prev && *prev != mc) prev = &(*prev)->mc_next;
6664 *prev = mc->mc_next;
6671 mdb_cursor_txn(MDB_cursor *mc)
6673 if (!mc) return NULL;
6678 mdb_cursor_dbi(MDB_cursor *mc)
6684 /** Replace the key for a node with a new key.
6685 * @param[in] mc Cursor pointing to the node to operate on.
6686 * @param[in] key The new key to use.
6687 * @return 0 on success, non-zero on failure.
6690 mdb_update_key(MDB_cursor *mc, MDB_val *key)
6697 indx_t ptr, i, numkeys, indx;
6700 indx = mc->mc_ki[mc->mc_top];
6701 mp = mc->mc_pg[mc->mc_top];
6702 node = NODEPTR(mp, indx);
6703 ptr = mp->mp_ptrs[indx];
6707 char kbuf2[(MDB_MAXKEYSIZE*2+1)];
6708 k2.mv_data = NODEKEY(node);
6709 k2.mv_size = node->mn_ksize;
6710 DPRINTF(("update key %u (ofs %u) [%s] to [%s] on page %"Z"u",
6712 mdb_dkey(&k2, kbuf2),
6718 delta0 = delta = key->mv_size - node->mn_ksize;
6720 /* Must be 2-byte aligned. If new key is
6721 * shorter by 1, the shift will be skipped.
6723 delta += (delta & 1);
6725 if (delta > 0 && SIZELEFT(mp) < delta) {
6727 /* not enough space left, do a delete and split */
6728 DPRINTF(("Not enough room, delta = %d, splitting...", delta));
6729 pgno = NODEPGNO(node);
6730 mdb_node_del(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], 0);
6731 return mdb_page_split(mc, key, NULL, pgno, MDB_SPLIT_REPLACE);
6734 numkeys = NUMKEYS(mp);
6735 for (i = 0; i < numkeys; i++) {
6736 if (mp->mp_ptrs[i] <= ptr)
6737 mp->mp_ptrs[i] -= delta;
6740 base = (char *)mp + mp->mp_upper;
6741 len = ptr - mp->mp_upper + NODESIZE;
6742 memmove(base - delta, base, len);
6743 mp->mp_upper -= delta;
6745 node = NODEPTR(mp, indx);
6748 /* But even if no shift was needed, update ksize */
6750 node->mn_ksize = key->mv_size;
6753 memcpy(NODEKEY(node), key->mv_data, key->mv_size);
6759 mdb_cursor_copy(const MDB_cursor *csrc, MDB_cursor *cdst);
6761 /** Move a node from csrc to cdst.
6764 mdb_node_move(MDB_cursor *csrc, MDB_cursor *cdst)
6771 unsigned short flags;
6775 /* Mark src and dst as dirty. */
6776 if ((rc = mdb_page_touch(csrc)) ||
6777 (rc = mdb_page_touch(cdst)))
6780 if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
6781 srcnode = NODEPTR(csrc->mc_pg[csrc->mc_top], 0); /* fake */
6782 key.mv_size = csrc->mc_db->md_pad;
6783 key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], csrc->mc_ki[csrc->mc_top], key.mv_size);
6785 data.mv_data = NULL;
6789 srcnode = NODEPTR(csrc->mc_pg[csrc->mc_top], csrc->mc_ki[csrc->mc_top]);
6790 assert(!((long)srcnode&1));
6791 srcpg = NODEPGNO(srcnode);
6792 flags = srcnode->mn_flags;
6793 if (csrc->mc_ki[csrc->mc_top] == 0 && IS_BRANCH(csrc->mc_pg[csrc->mc_top])) {
6794 unsigned int snum = csrc->mc_snum;
6796 /* must find the lowest key below src */
6797 mdb_page_search_lowest(csrc);
6798 if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
6799 key.mv_size = csrc->mc_db->md_pad;
6800 key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], 0, key.mv_size);
6802 s2 = NODEPTR(csrc->mc_pg[csrc->mc_top], 0);
6803 key.mv_size = NODEKSZ(s2);
6804 key.mv_data = NODEKEY(s2);
6806 csrc->mc_snum = snum--;
6807 csrc->mc_top = snum;
6809 key.mv_size = NODEKSZ(srcnode);
6810 key.mv_data = NODEKEY(srcnode);
6812 data.mv_size = NODEDSZ(srcnode);
6813 data.mv_data = NODEDATA(srcnode);
6815 if (IS_BRANCH(cdst->mc_pg[cdst->mc_top]) && cdst->mc_ki[cdst->mc_top] == 0) {
6816 unsigned int snum = cdst->mc_snum;
6819 /* must find the lowest key below dst */
6820 mdb_page_search_lowest(cdst);
6821 if (IS_LEAF2(cdst->mc_pg[cdst->mc_top])) {
6822 bkey.mv_size = cdst->mc_db->md_pad;
6823 bkey.mv_data = LEAF2KEY(cdst->mc_pg[cdst->mc_top], 0, bkey.mv_size);
6825 s2 = NODEPTR(cdst->mc_pg[cdst->mc_top], 0);
6826 bkey.mv_size = NODEKSZ(s2);
6827 bkey.mv_data = NODEKEY(s2);
6829 cdst->mc_snum = snum--;
6830 cdst->mc_top = snum;
6831 mdb_cursor_copy(cdst, &mn);
6833 rc = mdb_update_key(&mn, &bkey);
6838 DPRINTF(("moving %s node %u [%s] on page %"Z"u to node %u on page %"Z"u",
6839 IS_LEAF(csrc->mc_pg[csrc->mc_top]) ? "leaf" : "branch",
6840 csrc->mc_ki[csrc->mc_top],
6842 csrc->mc_pg[csrc->mc_top]->mp_pgno,
6843 cdst->mc_ki[cdst->mc_top], cdst->mc_pg[cdst->mc_top]->mp_pgno));
6845 /* Add the node to the destination page.
6847 rc = mdb_node_add(cdst, cdst->mc_ki[cdst->mc_top], &key, &data, srcpg, flags);
6848 if (rc != MDB_SUCCESS)
6851 /* Delete the node from the source page.
6853 mdb_node_del(csrc->mc_pg[csrc->mc_top], csrc->mc_ki[csrc->mc_top], key.mv_size);
6856 /* Adjust other cursors pointing to mp */
6857 MDB_cursor *m2, *m3;
6858 MDB_dbi dbi = csrc->mc_dbi;
6859 MDB_page *mp = csrc->mc_pg[csrc->mc_top];
6861 if (csrc->mc_flags & C_SUB)
6864 for (m2 = csrc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
6865 if (csrc->mc_flags & C_SUB)
6866 m3 = &m2->mc_xcursor->mx_cursor;
6869 if (m3 == csrc) continue;
6870 if (m3->mc_pg[csrc->mc_top] == mp && m3->mc_ki[csrc->mc_top] ==
6871 csrc->mc_ki[csrc->mc_top]) {
6872 m3->mc_pg[csrc->mc_top] = cdst->mc_pg[cdst->mc_top];
6873 m3->mc_ki[csrc->mc_top] = cdst->mc_ki[cdst->mc_top];
6878 /* Update the parent separators.
6880 if (csrc->mc_ki[csrc->mc_top] == 0) {
6881 if (csrc->mc_ki[csrc->mc_top-1] != 0) {
6882 if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
6883 key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], 0, key.mv_size);
6885 srcnode = NODEPTR(csrc->mc_pg[csrc->mc_top], 0);
6886 key.mv_size = NODEKSZ(srcnode);
6887 key.mv_data = NODEKEY(srcnode);
6889 DPRINTF(("update separator for source page %"Z"u to [%s]",
6890 csrc->mc_pg[csrc->mc_top]->mp_pgno, DKEY(&key)));
6891 mdb_cursor_copy(csrc, &mn);
6894 if ((rc = mdb_update_key(&mn, &key)) != MDB_SUCCESS)
6897 if (IS_BRANCH(csrc->mc_pg[csrc->mc_top])) {
6899 indx_t ix = csrc->mc_ki[csrc->mc_top];
6900 nullkey.mv_size = 0;
6901 csrc->mc_ki[csrc->mc_top] = 0;
6902 rc = mdb_update_key(csrc, &nullkey);
6903 csrc->mc_ki[csrc->mc_top] = ix;
6904 assert(rc == MDB_SUCCESS);
6908 if (cdst->mc_ki[cdst->mc_top] == 0) {
6909 if (cdst->mc_ki[cdst->mc_top-1] != 0) {
6910 if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
6911 key.mv_data = LEAF2KEY(cdst->mc_pg[cdst->mc_top], 0, key.mv_size);
6913 srcnode = NODEPTR(cdst->mc_pg[cdst->mc_top], 0);
6914 key.mv_size = NODEKSZ(srcnode);
6915 key.mv_data = NODEKEY(srcnode);
6917 DPRINTF(("update separator for destination page %"Z"u to [%s]",
6918 cdst->mc_pg[cdst->mc_top]->mp_pgno, DKEY(&key)));
6919 mdb_cursor_copy(cdst, &mn);
6922 if ((rc = mdb_update_key(&mn, &key)) != MDB_SUCCESS)
6925 if (IS_BRANCH(cdst->mc_pg[cdst->mc_top])) {
6927 indx_t ix = cdst->mc_ki[cdst->mc_top];
6928 nullkey.mv_size = 0;
6929 cdst->mc_ki[cdst->mc_top] = 0;
6930 rc = mdb_update_key(cdst, &nullkey);
6931 cdst->mc_ki[cdst->mc_top] = ix;
6932 assert(rc == MDB_SUCCESS);
6939 /** Merge one page into another.
6940 * The nodes from the page pointed to by \b csrc will
6941 * be copied to the page pointed to by \b cdst and then
6942 * the \b csrc page will be freed.
6943 * @param[in] csrc Cursor pointing to the source page.
6944 * @param[in] cdst Cursor pointing to the destination page.
6947 mdb_page_merge(MDB_cursor *csrc, MDB_cursor *cdst)
6955 DPRINTF(("merging page %"Z"u into %"Z"u", csrc->mc_pg[csrc->mc_top]->mp_pgno,
6956 cdst->mc_pg[cdst->mc_top]->mp_pgno));
6958 assert(csrc->mc_snum > 1); /* can't merge root page */
6959 assert(cdst->mc_snum > 1);
6961 /* Mark dst as dirty. */
6962 if ((rc = mdb_page_touch(cdst)))
6965 /* Move all nodes from src to dst.
6967 j = nkeys = NUMKEYS(cdst->mc_pg[cdst->mc_top]);
6968 if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
6969 key.mv_size = csrc->mc_db->md_pad;
6970 key.mv_data = METADATA(csrc->mc_pg[csrc->mc_top]);
6971 for (i = 0; i < NUMKEYS(csrc->mc_pg[csrc->mc_top]); i++, j++) {
6972 rc = mdb_node_add(cdst, j, &key, NULL, 0, 0);
6973 if (rc != MDB_SUCCESS)
6975 key.mv_data = (char *)key.mv_data + key.mv_size;
6978 for (i = 0; i < NUMKEYS(csrc->mc_pg[csrc->mc_top]); i++, j++) {
6979 srcnode = NODEPTR(csrc->mc_pg[csrc->mc_top], i);
6980 if (i == 0 && IS_BRANCH(csrc->mc_pg[csrc->mc_top])) {
6981 unsigned int snum = csrc->mc_snum;
6983 /* must find the lowest key below src */
6984 mdb_page_search_lowest(csrc);
6985 if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
6986 key.mv_size = csrc->mc_db->md_pad;
6987 key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], 0, key.mv_size);
6989 s2 = NODEPTR(csrc->mc_pg[csrc->mc_top], 0);
6990 key.mv_size = NODEKSZ(s2);
6991 key.mv_data = NODEKEY(s2);
6993 csrc->mc_snum = snum--;
6994 csrc->mc_top = snum;
6996 key.mv_size = srcnode->mn_ksize;
6997 key.mv_data = NODEKEY(srcnode);
7000 data.mv_size = NODEDSZ(srcnode);
7001 data.mv_data = NODEDATA(srcnode);
7002 rc = mdb_node_add(cdst, j, &key, &data, NODEPGNO(srcnode), srcnode->mn_flags);
7003 if (rc != MDB_SUCCESS)
7008 DPRINTF(("dst page %"Z"u now has %u keys (%.1f%% filled)",
7009 cdst->mc_pg[cdst->mc_top]->mp_pgno, NUMKEYS(cdst->mc_pg[cdst->mc_top]),
7010 (float)PAGEFILL(cdst->mc_txn->mt_env, cdst->mc_pg[cdst->mc_top]) / 10));
7012 /* Unlink the src page from parent and add to free list.
7014 mdb_node_del(csrc->mc_pg[csrc->mc_top-1], csrc->mc_ki[csrc->mc_top-1], 0);
7015 if (csrc->mc_ki[csrc->mc_top-1] == 0) {
7018 rc = mdb_update_key(csrc, &key);
7024 rc = mdb_midl_append(&csrc->mc_txn->mt_free_pgs,
7025 csrc->mc_pg[csrc->mc_top]->mp_pgno);
7028 if (IS_LEAF(csrc->mc_pg[csrc->mc_top]))
7029 csrc->mc_db->md_leaf_pages--;
7031 csrc->mc_db->md_branch_pages--;
7033 /* Adjust other cursors pointing to mp */
7034 MDB_cursor *m2, *m3;
7035 MDB_dbi dbi = csrc->mc_dbi;
7036 MDB_page *mp = cdst->mc_pg[cdst->mc_top];
7038 if (csrc->mc_flags & C_SUB)
7041 for (m2 = csrc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
7042 if (csrc->mc_flags & C_SUB)
7043 m3 = &m2->mc_xcursor->mx_cursor;
7046 if (m3 == csrc) continue;
7047 if (m3->mc_snum < csrc->mc_snum) continue;
7048 if (m3->mc_pg[csrc->mc_top] == csrc->mc_pg[csrc->mc_top]) {
7049 m3->mc_pg[csrc->mc_top] = mp;
7050 m3->mc_ki[csrc->mc_top] += nkeys;
7054 mdb_cursor_pop(csrc);
7056 return mdb_rebalance(csrc);
7059 /** Copy the contents of a cursor.
7060 * @param[in] csrc The cursor to copy from.
7061 * @param[out] cdst The cursor to copy to.
7064 mdb_cursor_copy(const MDB_cursor *csrc, MDB_cursor *cdst)
7068 cdst->mc_txn = csrc->mc_txn;
7069 cdst->mc_dbi = csrc->mc_dbi;
7070 cdst->mc_db = csrc->mc_db;
7071 cdst->mc_dbx = csrc->mc_dbx;
7072 cdst->mc_snum = csrc->mc_snum;
7073 cdst->mc_top = csrc->mc_top;
7074 cdst->mc_flags = csrc->mc_flags;
7076 for (i=0; i<csrc->mc_snum; i++) {
7077 cdst->mc_pg[i] = csrc->mc_pg[i];
7078 cdst->mc_ki[i] = csrc->mc_ki[i];
7082 /** Rebalance the tree after a delete operation.
7083 * @param[in] mc Cursor pointing to the page where rebalancing
7085 * @return 0 on success, non-zero on failure.
7088 mdb_rebalance(MDB_cursor *mc)
7092 unsigned int ptop, minkeys;
7095 minkeys = 1 + (IS_BRANCH(mc->mc_pg[mc->mc_top]));
7099 COPY_PGNO(pgno, mc->mc_pg[mc->mc_top]->mp_pgno);
7100 DPRINTF(("rebalancing %s page %"Z"u (has %u keys, %.1f%% full)",
7101 IS_LEAF(mc->mc_pg[mc->mc_top]) ? "leaf" : "branch",
7102 pgno, NUMKEYS(mc->mc_pg[mc->mc_top]),
7103 (float)PAGEFILL(mc->mc_txn->mt_env, mc->mc_pg[mc->mc_top]) / 10));
7107 if (PAGEFILL(mc->mc_txn->mt_env, mc->mc_pg[mc->mc_top]) >= FILL_THRESHOLD &&
7108 NUMKEYS(mc->mc_pg[mc->mc_top]) >= minkeys) {
7111 COPY_PGNO(pgno, mc->mc_pg[mc->mc_top]->mp_pgno);
7112 DPRINTF(("no need to rebalance page %"Z"u, above fill threshold",
7118 if (mc->mc_snum < 2) {
7119 MDB_page *mp = mc->mc_pg[0];
7121 DPUTS("Can't rebalance a subpage, ignoring");
7124 if (NUMKEYS(mp) == 0) {
7125 DPUTS("tree is completely empty");
7126 mc->mc_db->md_root = P_INVALID;
7127 mc->mc_db->md_depth = 0;
7128 mc->mc_db->md_leaf_pages = 0;
7129 rc = mdb_midl_append(&mc->mc_txn->mt_free_pgs, mp->mp_pgno);
7132 /* Adjust cursors pointing to mp */
7136 MDB_cursor *m2, *m3;
7137 MDB_dbi dbi = mc->mc_dbi;
7139 if (mc->mc_flags & C_SUB)
7142 for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
7143 if (mc->mc_flags & C_SUB)
7144 m3 = &m2->mc_xcursor->mx_cursor;
7147 if (m3->mc_snum < mc->mc_snum) continue;
7148 if (m3->mc_pg[0] == mp) {
7154 } else if (IS_BRANCH(mp) && NUMKEYS(mp) == 1) {
7155 DPUTS("collapsing root page!");
7156 rc = mdb_midl_append(&mc->mc_txn->mt_free_pgs, mp->mp_pgno);
7159 mc->mc_db->md_root = NODEPGNO(NODEPTR(mp, 0));
7160 rc = mdb_page_get(mc->mc_txn,mc->mc_db->md_root,&mc->mc_pg[0],NULL);
7163 mc->mc_db->md_depth--;
7164 mc->mc_db->md_branch_pages--;
7165 mc->mc_ki[0] = mc->mc_ki[1];
7167 /* Adjust other cursors pointing to mp */
7168 MDB_cursor *m2, *m3;
7169 MDB_dbi dbi = mc->mc_dbi;
7171 if (mc->mc_flags & C_SUB)
7174 for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
7175 if (mc->mc_flags & C_SUB)
7176 m3 = &m2->mc_xcursor->mx_cursor;
7179 if (m3 == mc || m3->mc_snum < mc->mc_snum) continue;
7180 if (m3->mc_pg[0] == mp) {
7181 m3->mc_pg[0] = mc->mc_pg[0];
7184 m3->mc_ki[0] = m3->mc_ki[1];
7189 DPUTS("root page doesn't need rebalancing");
7193 /* The parent (branch page) must have at least 2 pointers,
7194 * otherwise the tree is invalid.
7196 ptop = mc->mc_top-1;
7197 assert(NUMKEYS(mc->mc_pg[ptop]) > 1);
7199 /* Leaf page fill factor is below the threshold.
7200 * Try to move keys from left or right neighbor, or
7201 * merge with a neighbor page.
7206 mdb_cursor_copy(mc, &mn);
7207 mn.mc_xcursor = NULL;
7209 if (mc->mc_ki[ptop] == 0) {
7210 /* We're the leftmost leaf in our parent.
7212 DPUTS("reading right neighbor");
7214 node = NODEPTR(mc->mc_pg[ptop], mn.mc_ki[ptop]);
7215 rc = mdb_page_get(mc->mc_txn,NODEPGNO(node),&mn.mc_pg[mn.mc_top],NULL);
7218 mn.mc_ki[mn.mc_top] = 0;
7219 mc->mc_ki[mc->mc_top] = NUMKEYS(mc->mc_pg[mc->mc_top]);
7221 /* There is at least one neighbor to the left.
7223 DPUTS("reading left neighbor");
7225 node = NODEPTR(mc->mc_pg[ptop], mn.mc_ki[ptop]);
7226 rc = mdb_page_get(mc->mc_txn,NODEPGNO(node),&mn.mc_pg[mn.mc_top],NULL);
7229 mn.mc_ki[mn.mc_top] = NUMKEYS(mn.mc_pg[mn.mc_top]) - 1;
7230 mc->mc_ki[mc->mc_top] = 0;
7233 DPRINTF(("found neighbor page %"Z"u (%u keys, %.1f%% full)",
7234 mn.mc_pg[mn.mc_top]->mp_pgno, NUMKEYS(mn.mc_pg[mn.mc_top]),
7235 (float)PAGEFILL(mc->mc_txn->mt_env, mn.mc_pg[mn.mc_top]) / 10));
7237 /* If the neighbor page is above threshold and has enough keys,
7238 * move one key from it. Otherwise we should try to merge them.
7239 * (A branch page must never have less than 2 keys.)
7241 minkeys = 1 + (IS_BRANCH(mn.mc_pg[mn.mc_top]));
7242 if (PAGEFILL(mc->mc_txn->mt_env, mn.mc_pg[mn.mc_top]) >= FILL_THRESHOLD && NUMKEYS(mn.mc_pg[mn.mc_top]) > minkeys)
7243 return mdb_node_move(&mn, mc);
7245 if (mc->mc_ki[ptop] == 0)
7246 rc = mdb_page_merge(&mn, mc);
7248 rc = mdb_page_merge(mc, &mn);
7249 mc->mc_flags &= ~(C_INITIALIZED|C_EOF);
7254 /** Complete a delete operation started by #mdb_cursor_del(). */
7256 mdb_cursor_del0(MDB_cursor *mc, MDB_node *leaf)
7263 mp = mc->mc_pg[mc->mc_top];
7264 ki = mc->mc_ki[mc->mc_top];
7266 /* add overflow pages to free list */
7267 if (!IS_LEAF2(mp) && F_ISSET(leaf->mn_flags, F_BIGDATA)) {
7271 memcpy(&pg, NODEDATA(leaf), sizeof(pg));
7272 if ((rc = mdb_page_get(mc->mc_txn, pg, &omp, NULL)) ||
7273 (rc = mdb_ovpage_free(mc, omp)))
7276 mdb_node_del(mp, ki, mc->mc_db->md_pad);
7277 mc->mc_db->md_entries--;
7278 rc = mdb_rebalance(mc);
7279 if (rc != MDB_SUCCESS)
7280 mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
7283 MDB_dbi dbi = mc->mc_dbi;
7285 mp = mc->mc_pg[mc->mc_top];
7286 nkeys = NUMKEYS(mp);
7288 /* if mc points past last node in page, find next sibling */
7289 if (mc->mc_ki[mc->mc_top] >= nkeys)
7290 mdb_cursor_sibling(mc, 1);
7292 /* Adjust other cursors pointing to mp */
7293 for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
7296 if (!(m2->mc_flags & C_INITIALIZED))
7298 if (m2->mc_pg[mc->mc_top] == mp) {
7299 if (m2->mc_ki[mc->mc_top] >= ki) {
7300 m2->mc_flags |= C_DEL;
7301 if (m2->mc_ki[mc->mc_top] > ki)
7302 m2->mc_ki[mc->mc_top]--;
7304 if (m2->mc_ki[mc->mc_top] >= nkeys)
7305 mdb_cursor_sibling(m2, 1);
7308 mc->mc_flags |= C_DEL;
7315 mdb_del(MDB_txn *txn, MDB_dbi dbi,
7316 MDB_val *key, MDB_val *data)
7321 MDB_val rdata, *xdata;
7325 assert(key != NULL);
7327 DPRINTF(("====> delete db %u key [%s]", dbi, DKEY(key)));
7329 if (txn == NULL || !dbi || dbi >= txn->mt_numdbs || !(txn->mt_dbflags[dbi] & DB_VALID))
7332 if (txn->mt_flags & (MDB_TXN_RDONLY|MDB_TXN_ERROR))
7333 return (txn->mt_flags & MDB_TXN_RDONLY) ? EACCES : MDB_BAD_TXN;
7335 if (key->mv_size == 0 || key->mv_size > MDB_MAXKEYSIZE) {
7336 return MDB_BAD_VALSIZE;
7339 mdb_cursor_init(&mc, txn, dbi, &mx);
7342 if (!F_ISSET(txn->mt_dbs[dbi].md_flags, MDB_DUPSORT)) {
7343 /* must ignore any data */
7354 rc = mdb_cursor_set(&mc, key, xdata, op, &exact);
7356 /* let mdb_page_split know about this cursor if needed:
7357 * delete will trigger a rebalance; if it needs to move
7358 * a node from one page to another, it will have to
7359 * update the parent's separator key(s). If the new sepkey
7360 * is larger than the current one, the parent page may
7361 * run out of space, triggering a split. We need this
7362 * cursor to be consistent until the end of the rebalance.
7364 mc.mc_flags |= C_UNTRACK;
7365 mc.mc_next = txn->mt_cursors[dbi];
7366 txn->mt_cursors[dbi] = &mc;
7367 rc = mdb_cursor_del(&mc, data ? 0 : MDB_NODUPDATA);
7368 txn->mt_cursors[dbi] = mc.mc_next;
7373 /** Split a page and insert a new node.
7374 * @param[in,out] mc Cursor pointing to the page and desired insertion index.
7375 * The cursor will be updated to point to the actual page and index where
7376 * the node got inserted after the split.
7377 * @param[in] newkey The key for the newly inserted node.
7378 * @param[in] newdata The data for the newly inserted node.
7379 * @param[in] newpgno The page number, if the new node is a branch node.
7380 * @param[in] nflags The #NODE_ADD_FLAGS for the new node.
7381 * @return 0 on success, non-zero on failure.
7384 mdb_page_split(MDB_cursor *mc, MDB_val *newkey, MDB_val *newdata, pgno_t newpgno,
7385 unsigned int nflags)
7388 int rc = MDB_SUCCESS, ins_new = 0, new_root = 0, newpos = 1, did_split = 0;
7391 unsigned int i, j, split_indx, nkeys, pmax;
7393 MDB_val sepkey, rkey, xdata, *rdata = &xdata;
7395 MDB_page *mp, *rp, *pp;
7400 mp = mc->mc_pg[mc->mc_top];
7401 newindx = mc->mc_ki[mc->mc_top];
7403 DPRINTF(("-----> splitting %s page %"Z"u and adding [%s] at index %i",
7404 IS_LEAF(mp) ? "leaf" : "branch", mp->mp_pgno,
7405 DKEY(newkey), mc->mc_ki[mc->mc_top]));
7407 /* Create a right sibling. */
7408 if ((rc = mdb_page_new(mc, mp->mp_flags, 1, &rp)))
7410 DPRINTF(("new right sibling: page %"Z"u", rp->mp_pgno));
7412 if (mc->mc_snum < 2) {
7413 if ((rc = mdb_page_new(mc, P_BRANCH, 1, &pp)))
7415 /* shift current top to make room for new parent */
7416 mc->mc_pg[1] = mc->mc_pg[0];
7417 mc->mc_ki[1] = mc->mc_ki[0];
7420 mc->mc_db->md_root = pp->mp_pgno;
7421 DPRINTF(("root split! new root = %"Z"u", pp->mp_pgno));
7422 mc->mc_db->md_depth++;
7425 /* Add left (implicit) pointer. */
7426 if ((rc = mdb_node_add(mc, 0, NULL, NULL, mp->mp_pgno, 0)) != MDB_SUCCESS) {
7427 /* undo the pre-push */
7428 mc->mc_pg[0] = mc->mc_pg[1];
7429 mc->mc_ki[0] = mc->mc_ki[1];
7430 mc->mc_db->md_root = mp->mp_pgno;
7431 mc->mc_db->md_depth--;
7438 ptop = mc->mc_top-1;
7439 DPRINTF(("parent branch page is %"Z"u", mc->mc_pg[ptop]->mp_pgno));
7442 mc->mc_flags |= C_SPLITTING;
7443 mdb_cursor_copy(mc, &mn);
7444 mn.mc_pg[mn.mc_top] = rp;
7445 mn.mc_ki[ptop] = mc->mc_ki[ptop]+1;
7447 if (nflags & MDB_APPEND) {
7448 mn.mc_ki[mn.mc_top] = 0;
7450 split_indx = newindx;
7455 nkeys = NUMKEYS(mp);
7456 split_indx = nkeys / 2;
7457 if (newindx < split_indx)
7463 unsigned int lsize, rsize, ksize;
7464 /* Move half of the keys to the right sibling */
7466 x = mc->mc_ki[mc->mc_top] - split_indx;
7467 ksize = mc->mc_db->md_pad;
7468 split = LEAF2KEY(mp, split_indx, ksize);
7469 rsize = (nkeys - split_indx) * ksize;
7470 lsize = (nkeys - split_indx) * sizeof(indx_t);
7471 mp->mp_lower -= lsize;
7472 rp->mp_lower += lsize;
7473 mp->mp_upper += rsize - lsize;
7474 rp->mp_upper -= rsize - lsize;
7475 sepkey.mv_size = ksize;
7476 if (newindx == split_indx) {
7477 sepkey.mv_data = newkey->mv_data;
7479 sepkey.mv_data = split;
7482 ins = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], ksize);
7483 memcpy(rp->mp_ptrs, split, rsize);
7484 sepkey.mv_data = rp->mp_ptrs;
7485 memmove(ins+ksize, ins, (split_indx - mc->mc_ki[mc->mc_top]) * ksize);
7486 memcpy(ins, newkey->mv_data, ksize);
7487 mp->mp_lower += sizeof(indx_t);
7488 mp->mp_upper -= ksize - sizeof(indx_t);
7491 memcpy(rp->mp_ptrs, split, x * ksize);
7492 ins = LEAF2KEY(rp, x, ksize);
7493 memcpy(ins, newkey->mv_data, ksize);
7494 memcpy(ins+ksize, split + x * ksize, rsize - x * ksize);
7495 rp->mp_lower += sizeof(indx_t);
7496 rp->mp_upper -= ksize - sizeof(indx_t);
7497 mc->mc_ki[mc->mc_top] = x;
7498 mc->mc_pg[mc->mc_top] = rp;
7503 /* For leaf pages, check the split point based on what
7504 * fits where, since otherwise mdb_node_add can fail.
7506 * This check is only needed when the data items are
7507 * relatively large, such that being off by one will
7508 * make the difference between success or failure.
7510 * It's also relevant if a page happens to be laid out
7511 * such that one half of its nodes are all "small" and
7512 * the other half of its nodes are "large." If the new
7513 * item is also "large" and falls on the half with
7514 * "large" nodes, it also may not fit.
7517 unsigned int psize, nsize;
7518 /* Maximum free space in an empty page */
7519 pmax = mc->mc_txn->mt_env->me_psize - PAGEHDRSZ;
7520 nsize = mdb_leaf_size(mc->mc_txn->mt_env, newkey, newdata);
7521 if ((nkeys < 20) || (nsize > pmax/16)) {
7522 if (newindx <= split_indx) {
7525 for (i=0; i<split_indx; i++) {
7526 node = NODEPTR(mp, i);
7527 psize += NODESIZE + NODEKSZ(node) + sizeof(indx_t);
7528 if (F_ISSET(node->mn_flags, F_BIGDATA))
7529 psize += sizeof(pgno_t);
7531 psize += NODEDSZ(node);
7535 split_indx = newindx;
7546 for (i=nkeys-1; i>=split_indx; i--) {
7547 node = NODEPTR(mp, i);
7548 psize += NODESIZE + NODEKSZ(node) + sizeof(indx_t);
7549 if (F_ISSET(node->mn_flags, F_BIGDATA))
7550 psize += sizeof(pgno_t);
7552 psize += NODEDSZ(node);
7556 split_indx = newindx;
7567 /* First find the separating key between the split pages.
7568 * The case where newindx == split_indx is ambiguous; the
7569 * new item could go to the new page or stay on the original
7570 * page. If newpos == 1 it goes to the new page.
7572 if (newindx == split_indx && newpos) {
7573 sepkey.mv_size = newkey->mv_size;
7574 sepkey.mv_data = newkey->mv_data;
7576 node = NODEPTR(mp, split_indx);
7577 sepkey.mv_size = node->mn_ksize;
7578 sepkey.mv_data = NODEKEY(node);
7582 DPRINTF(("separator is [%s]", DKEY(&sepkey)));
7584 /* Copy separator key to the parent.
7586 if (SIZELEFT(mn.mc_pg[ptop]) < mdb_branch_size(mc->mc_txn->mt_env, &sepkey)) {
7590 rc = mdb_page_split(&mn, &sepkey, NULL, rp->mp_pgno, 0);
7593 if (mn.mc_snum == mc->mc_snum) {
7594 mc->mc_pg[mc->mc_snum] = mc->mc_pg[mc->mc_top];
7595 mc->mc_ki[mc->mc_snum] = mc->mc_ki[mc->mc_top];
7596 mc->mc_pg[mc->mc_top] = mc->mc_pg[ptop];
7597 mc->mc_ki[mc->mc_top] = mc->mc_ki[ptop];
7602 /* Right page might now have changed parent.
7603 * Check if left page also changed parent.
7605 if (mn.mc_pg[ptop] != mc->mc_pg[ptop] &&
7606 mc->mc_ki[ptop] >= NUMKEYS(mc->mc_pg[ptop])) {
7607 for (i=0; i<ptop; i++) {
7608 mc->mc_pg[i] = mn.mc_pg[i];
7609 mc->mc_ki[i] = mn.mc_ki[i];
7611 mc->mc_pg[ptop] = mn.mc_pg[ptop];
7612 mc->mc_ki[ptop] = mn.mc_ki[ptop] - 1;
7616 rc = mdb_node_add(&mn, mn.mc_ki[ptop], &sepkey, NULL, rp->mp_pgno, 0);
7619 mc->mc_flags ^= C_SPLITTING;
7620 if (rc != MDB_SUCCESS) {
7623 if (nflags & MDB_APPEND) {
7624 mc->mc_pg[mc->mc_top] = rp;
7625 mc->mc_ki[mc->mc_top] = 0;
7626 rc = mdb_node_add(mc, 0, newkey, newdata, newpgno, nflags);
7629 for (i=0; i<mc->mc_top; i++)
7630 mc->mc_ki[i] = mn.mc_ki[i];
7637 /* Move half of the keys to the right sibling. */
7639 /* grab a page to hold a temporary copy */
7640 copy = mdb_page_malloc(mc->mc_txn, 1);
7644 copy->mp_pgno = mp->mp_pgno;
7645 copy->mp_flags = mp->mp_flags;
7646 copy->mp_lower = PAGEHDRSZ;
7647 copy->mp_upper = mc->mc_txn->mt_env->me_psize;
7648 mc->mc_pg[mc->mc_top] = copy;
7649 for (i = j = 0; i <= nkeys; j++) {
7650 if (i == split_indx) {
7651 /* Insert in right sibling. */
7652 /* Reset insert index for right sibling. */
7653 if (i != newindx || (newpos ^ ins_new)) {
7655 mc->mc_pg[mc->mc_top] = rp;
7659 if (i == newindx && !ins_new) {
7660 /* Insert the original entry that caused the split. */
7661 rkey.mv_data = newkey->mv_data;
7662 rkey.mv_size = newkey->mv_size;
7671 /* Update index for the new key. */
7672 mc->mc_ki[mc->mc_top] = j;
7673 } else if (i == nkeys) {
7676 node = NODEPTR(mp, i);
7677 rkey.mv_data = NODEKEY(node);
7678 rkey.mv_size = node->mn_ksize;
7680 xdata.mv_data = NODEDATA(node);
7681 xdata.mv_size = NODEDSZ(node);
7684 pgno = NODEPGNO(node);
7685 flags = node->mn_flags;
7690 if (!IS_LEAF(mp) && j == 0) {
7691 /* First branch index doesn't need key data. */
7695 rc = mdb_node_add(mc, j, &rkey, rdata, pgno, flags);
7699 nkeys = NUMKEYS(copy);
7700 for (i=0; i<nkeys; i++)
7701 mp->mp_ptrs[i] = copy->mp_ptrs[i];
7702 mp->mp_lower = copy->mp_lower;
7703 mp->mp_upper = copy->mp_upper;
7704 memcpy(NODEPTR(mp, nkeys-1), NODEPTR(copy, nkeys-1),
7705 mc->mc_txn->mt_env->me_psize - copy->mp_upper);
7707 /* reset back to original page */
7708 if (newindx < split_indx || (!newpos && newindx == split_indx)) {
7709 mc->mc_pg[mc->mc_top] = mp;
7710 if (nflags & MDB_RESERVE) {
7711 node = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
7712 if (!(node->mn_flags & F_BIGDATA))
7713 newdata->mv_data = NODEDATA(node);
7717 /* Make sure mc_ki is still valid.
7719 if (mn.mc_pg[ptop] != mc->mc_pg[ptop] &&
7720 mc->mc_ki[ptop] >= NUMKEYS(mc->mc_pg[ptop])) {
7721 for (i=0; i<ptop; i++) {
7722 mc->mc_pg[i] = mn.mc_pg[i];
7723 mc->mc_ki[i] = mn.mc_ki[i];
7725 mc->mc_pg[ptop] = mn.mc_pg[ptop];
7726 mc->mc_ki[ptop] = mn.mc_ki[ptop] - 1;
7730 /* return tmp page to freelist */
7731 mdb_page_free(mc->mc_txn->mt_env, copy);
7734 /* Adjust other cursors pointing to mp */
7735 MDB_cursor *m2, *m3;
7736 MDB_dbi dbi = mc->mc_dbi;
7737 int fixup = NUMKEYS(mp);
7739 if (mc->mc_flags & C_SUB)
7742 for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
7743 if (mc->mc_flags & C_SUB)
7744 m3 = &m2->mc_xcursor->mx_cursor;
7749 if (!(m2->mc_flags & m3->mc_flags & C_INITIALIZED))
7751 if (m3->mc_flags & C_SPLITTING)
7756 for (k=m3->mc_top; k>=0; k--) {
7757 m3->mc_ki[k+1] = m3->mc_ki[k];
7758 m3->mc_pg[k+1] = m3->mc_pg[k];
7760 if (m3->mc_ki[0] >= split_indx) {
7765 m3->mc_pg[0] = mc->mc_pg[0];
7769 if (m3->mc_top >= mc->mc_top && m3->mc_pg[mc->mc_top] == mp) {
7770 if (m3->mc_ki[mc->mc_top] >= newindx && !(nflags & MDB_SPLIT_REPLACE))
7771 m3->mc_ki[mc->mc_top]++;
7772 if (m3->mc_ki[mc->mc_top] >= fixup) {
7773 m3->mc_pg[mc->mc_top] = rp;
7774 m3->mc_ki[mc->mc_top] -= fixup;
7775 m3->mc_ki[ptop] = mn.mc_ki[ptop];
7777 } else if (!did_split && m3->mc_top >= ptop && m3->mc_pg[ptop] == mc->mc_pg[ptop] &&
7778 m3->mc_ki[ptop] >= mc->mc_ki[ptop]) {
7787 mdb_put(MDB_txn *txn, MDB_dbi dbi,
7788 MDB_val *key, MDB_val *data, unsigned int flags)
7793 assert(key != NULL);
7794 assert(data != NULL);
7796 if (txn == NULL || !dbi || dbi >= txn->mt_numdbs || !(txn->mt_dbflags[dbi] & DB_VALID))
7799 if (txn->mt_flags & (MDB_TXN_RDONLY|MDB_TXN_ERROR))
7800 return (txn->mt_flags & MDB_TXN_RDONLY) ? EACCES : MDB_BAD_TXN;
7802 if (key->mv_size == 0 || key->mv_size > MDB_MAXKEYSIZE) {
7803 return MDB_BAD_VALSIZE;
7806 if ((flags & (MDB_NOOVERWRITE|MDB_NODUPDATA|MDB_RESERVE|MDB_APPEND|MDB_APPENDDUP)) != flags)
7809 mdb_cursor_init(&mc, txn, dbi, &mx);
7810 return mdb_cursor_put(&mc, key, data, flags);
7814 mdb_env_set_flags(MDB_env *env, unsigned int flag, int onoff)
7816 if ((flag & CHANGEABLE) != flag)
7819 env->me_flags |= flag;
7821 env->me_flags &= ~flag;
7826 mdb_env_get_flags(MDB_env *env, unsigned int *arg)
7831 *arg = env->me_flags;
7836 mdb_env_get_path(MDB_env *env, const char **arg)
7841 *arg = env->me_path;
7845 /** Common code for #mdb_stat() and #mdb_env_stat().
7846 * @param[in] env the environment to operate in.
7847 * @param[in] db the #MDB_db record containing the stats to return.
7848 * @param[out] arg the address of an #MDB_stat structure to receive the stats.
7849 * @return 0, this function always succeeds.
7852 mdb_stat0(MDB_env *env, MDB_db *db, MDB_stat *arg)
7854 arg->ms_psize = env->me_psize;
7855 arg->ms_depth = db->md_depth;
7856 arg->ms_branch_pages = db->md_branch_pages;
7857 arg->ms_leaf_pages = db->md_leaf_pages;
7858 arg->ms_overflow_pages = db->md_overflow_pages;
7859 arg->ms_entries = db->md_entries;
7864 mdb_env_stat(MDB_env *env, MDB_stat *arg)
7868 if (env == NULL || arg == NULL)
7871 toggle = mdb_env_pick_meta(env);
7873 return mdb_stat0(env, &env->me_metas[toggle]->mm_dbs[MAIN_DBI], arg);
7877 mdb_env_info(MDB_env *env, MDB_envinfo *arg)
7881 if (env == NULL || arg == NULL)
7884 toggle = mdb_env_pick_meta(env);
7885 arg->me_mapaddr = (env->me_flags & MDB_FIXEDMAP) ? env->me_map : 0;
7886 arg->me_mapsize = env->me_mapsize;
7887 arg->me_maxreaders = env->me_maxreaders;
7889 /* me_numreaders may be zero if this process never used any readers. Use
7890 * the shared numreader count if it exists.
7892 arg->me_numreaders = env->me_txns ? env->me_txns->mti_numreaders : env->me_numreaders;
7894 arg->me_last_pgno = env->me_metas[toggle]->mm_last_pg;
7895 arg->me_last_txnid = env->me_metas[toggle]->mm_txnid;
7899 /** Set the default comparison functions for a database.
7900 * Called immediately after a database is opened to set the defaults.
7901 * The user can then override them with #mdb_set_compare() or
7902 * #mdb_set_dupsort().
7903 * @param[in] txn A transaction handle returned by #mdb_txn_begin()
7904 * @param[in] dbi A database handle returned by #mdb_dbi_open()
7907 mdb_default_cmp(MDB_txn *txn, MDB_dbi dbi)
7909 uint16_t f = txn->mt_dbs[dbi].md_flags;
7911 txn->mt_dbxs[dbi].md_cmp =
7912 (f & MDB_REVERSEKEY) ? mdb_cmp_memnr :
7913 (f & MDB_INTEGERKEY) ? mdb_cmp_cint : mdb_cmp_memn;
7915 txn->mt_dbxs[dbi].md_dcmp =
7916 !(f & MDB_DUPSORT) ? 0 :
7917 ((f & MDB_INTEGERDUP)
7918 ? ((f & MDB_DUPFIXED) ? mdb_cmp_int : mdb_cmp_cint)
7919 : ((f & MDB_REVERSEDUP) ? mdb_cmp_memnr : mdb_cmp_memn));
7922 int mdb_dbi_open(MDB_txn *txn, const char *name, unsigned int flags, MDB_dbi *dbi)
7927 int rc, dbflag, exact;
7928 unsigned int unused = 0;
7931 if (txn->mt_dbxs[FREE_DBI].md_cmp == NULL) {
7932 mdb_default_cmp(txn, FREE_DBI);
7935 if ((flags & VALID_FLAGS) != flags)
7937 if (txn->mt_flags & MDB_TXN_ERROR)
7943 if (flags & PERSISTENT_FLAGS) {
7944 uint16_t f2 = flags & PERSISTENT_FLAGS;
7945 /* make sure flag changes get committed */
7946 if ((txn->mt_dbs[MAIN_DBI].md_flags | f2) != txn->mt_dbs[MAIN_DBI].md_flags) {
7947 txn->mt_dbs[MAIN_DBI].md_flags |= f2;
7948 txn->mt_flags |= MDB_TXN_DIRTY;
7951 mdb_default_cmp(txn, MAIN_DBI);
7955 if (txn->mt_dbxs[MAIN_DBI].md_cmp == NULL) {
7956 mdb_default_cmp(txn, MAIN_DBI);
7959 /* Is the DB already open? */
7961 for (i=2; i<txn->mt_numdbs; i++) {
7962 if (!txn->mt_dbxs[i].md_name.mv_size) {
7963 /* Remember this free slot */
7964 if (!unused) unused = i;
7967 if (len == txn->mt_dbxs[i].md_name.mv_size &&
7968 !strncmp(name, txn->mt_dbxs[i].md_name.mv_data, len)) {
7974 /* If no free slot and max hit, fail */
7975 if (!unused && txn->mt_numdbs >= txn->mt_env->me_maxdbs)
7976 return MDB_DBS_FULL;
7978 /* Cannot mix named databases with some mainDB flags */
7979 if (txn->mt_dbs[MAIN_DBI].md_flags & (MDB_DUPSORT|MDB_INTEGERKEY))
7980 return (flags & MDB_CREATE) ? MDB_INCOMPATIBLE : MDB_NOTFOUND;
7982 /* Find the DB info */
7983 dbflag = DB_NEW|DB_VALID;
7986 key.mv_data = (void *)name;
7987 mdb_cursor_init(&mc, txn, MAIN_DBI, NULL);
7988 rc = mdb_cursor_set(&mc, &key, &data, MDB_SET, &exact);
7989 if (rc == MDB_SUCCESS) {
7990 /* make sure this is actually a DB */
7991 MDB_node *node = NODEPTR(mc.mc_pg[mc.mc_top], mc.mc_ki[mc.mc_top]);
7992 if (!(node->mn_flags & F_SUBDATA))
7993 return MDB_INCOMPATIBLE;
7994 } else if (rc == MDB_NOTFOUND && (flags & MDB_CREATE)) {
7995 /* Create if requested */
7997 data.mv_size = sizeof(MDB_db);
7998 data.mv_data = &dummy;
7999 memset(&dummy, 0, sizeof(dummy));
8000 dummy.md_root = P_INVALID;
8001 dummy.md_flags = flags & PERSISTENT_FLAGS;
8002 rc = mdb_cursor_put(&mc, &key, &data, F_SUBDATA);
8006 /* OK, got info, add to table */
8007 if (rc == MDB_SUCCESS) {
8008 unsigned int slot = unused ? unused : txn->mt_numdbs;
8009 txn->mt_dbxs[slot].md_name.mv_data = strdup(name);
8010 txn->mt_dbxs[slot].md_name.mv_size = len;
8011 txn->mt_dbxs[slot].md_rel = NULL;
8012 txn->mt_dbflags[slot] = dbflag;
8013 memcpy(&txn->mt_dbs[slot], data.mv_data, sizeof(MDB_db));
8015 mdb_default_cmp(txn, slot);
8024 int mdb_stat(MDB_txn *txn, MDB_dbi dbi, MDB_stat *arg)
8026 if (txn == NULL || arg == NULL || dbi >= txn->mt_numdbs)
8029 if (txn->mt_dbflags[dbi] & DB_STALE) {
8032 /* Stale, must read the DB's root. cursor_init does it for us. */
8033 mdb_cursor_init(&mc, txn, dbi, &mx);
8035 return mdb_stat0(txn->mt_env, &txn->mt_dbs[dbi], arg);
8038 void mdb_dbi_close(MDB_env *env, MDB_dbi dbi)
8041 if (dbi <= MAIN_DBI || dbi >= env->me_maxdbs)
8043 ptr = env->me_dbxs[dbi].md_name.mv_data;
8044 env->me_dbxs[dbi].md_name.mv_data = NULL;
8045 env->me_dbxs[dbi].md_name.mv_size = 0;
8046 env->me_dbflags[dbi] = 0;
8050 int mdb_dbi_flags(MDB_txn *txn, MDB_dbi dbi, unsigned int *flags)
8052 /* We could return the flags for the FREE_DBI too but what's the point? */
8053 if (txn == NULL || dbi < MAIN_DBI || dbi >= txn->mt_numdbs)
8055 *flags = txn->mt_dbs[dbi].md_flags & PERSISTENT_FLAGS;
8059 /** Add all the DB's pages to the free list.
8060 * @param[in] mc Cursor on the DB to free.
8061 * @param[in] subs non-Zero to check for sub-DBs in this DB.
8062 * @return 0 on success, non-zero on failure.
8065 mdb_drop0(MDB_cursor *mc, int subs)
8069 rc = mdb_page_search(mc, NULL, 0);
8070 if (rc == MDB_SUCCESS) {
8071 MDB_txn *txn = mc->mc_txn;
8076 /* LEAF2 pages have no nodes, cannot have sub-DBs */
8077 if (IS_LEAF2(mc->mc_pg[mc->mc_top]))
8080 mdb_cursor_copy(mc, &mx);
8081 while (mc->mc_snum > 0) {
8082 MDB_page *mp = mc->mc_pg[mc->mc_top];
8083 unsigned n = NUMKEYS(mp);
8085 for (i=0; i<n; i++) {
8086 ni = NODEPTR(mp, i);
8087 if (ni->mn_flags & F_BIGDATA) {
8090 memcpy(&pg, NODEDATA(ni), sizeof(pg));
8091 rc = mdb_page_get(txn, pg, &omp, NULL);
8094 assert(IS_OVERFLOW(omp));
8095 rc = mdb_midl_append_range(&txn->mt_free_pgs,
8099 } else if (subs && (ni->mn_flags & F_SUBDATA)) {
8100 mdb_xcursor_init1(mc, ni);
8101 rc = mdb_drop0(&mc->mc_xcursor->mx_cursor, 0);
8107 if ((rc = mdb_midl_need(&txn->mt_free_pgs, n)) != 0)
8109 for (i=0; i<n; i++) {
8111 ni = NODEPTR(mp, i);
8114 mdb_midl_xappend(txn->mt_free_pgs, pg);
8119 mc->mc_ki[mc->mc_top] = i;
8120 rc = mdb_cursor_sibling(mc, 1);
8122 /* no more siblings, go back to beginning
8123 * of previous level.
8127 for (i=1; i<mc->mc_snum; i++) {
8129 mc->mc_pg[i] = mx.mc_pg[i];
8134 rc = mdb_midl_append(&txn->mt_free_pgs, mc->mc_db->md_root);
8135 } else if (rc == MDB_NOTFOUND) {
8141 int mdb_drop(MDB_txn *txn, MDB_dbi dbi, int del)
8143 MDB_cursor *mc, *m2;
8146 if (!txn || !dbi || dbi >= txn->mt_numdbs || (unsigned)del > 1 || !(txn->mt_dbflags[dbi] & DB_VALID))
8149 if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY))
8152 rc = mdb_cursor_open(txn, dbi, &mc);
8156 rc = mdb_drop0(mc, mc->mc_db->md_flags & MDB_DUPSORT);
8157 /* Invalidate the dropped DB's cursors */
8158 for (m2 = txn->mt_cursors[dbi]; m2; m2 = m2->mc_next)
8159 m2->mc_flags &= ~(C_INITIALIZED|C_EOF);
8163 /* Can't delete the main DB */
8164 if (del && dbi > MAIN_DBI) {
8165 rc = mdb_del(txn, MAIN_DBI, &mc->mc_dbx->md_name, NULL);
8167 txn->mt_dbflags[dbi] = DB_STALE;
8168 mdb_dbi_close(txn->mt_env, dbi);
8171 /* reset the DB record, mark it dirty */
8172 txn->mt_dbflags[dbi] |= DB_DIRTY;
8173 txn->mt_dbs[dbi].md_depth = 0;
8174 txn->mt_dbs[dbi].md_branch_pages = 0;
8175 txn->mt_dbs[dbi].md_leaf_pages = 0;
8176 txn->mt_dbs[dbi].md_overflow_pages = 0;
8177 txn->mt_dbs[dbi].md_entries = 0;
8178 txn->mt_dbs[dbi].md_root = P_INVALID;
8180 txn->mt_flags |= MDB_TXN_DIRTY;
8183 mdb_cursor_close(mc);
8187 int mdb_set_compare(MDB_txn *txn, MDB_dbi dbi, MDB_cmp_func *cmp)
8189 if (txn == NULL || !dbi || dbi >= txn->mt_numdbs || !(txn->mt_dbflags[dbi] & DB_VALID))
8192 txn->mt_dbxs[dbi].md_cmp = cmp;
8196 int mdb_set_dupsort(MDB_txn *txn, MDB_dbi dbi, MDB_cmp_func *cmp)
8198 if (txn == NULL || !dbi || dbi >= txn->mt_numdbs || !(txn->mt_dbflags[dbi] & DB_VALID))
8201 txn->mt_dbxs[dbi].md_dcmp = cmp;
8205 int mdb_set_relfunc(MDB_txn *txn, MDB_dbi dbi, MDB_rel_func *rel)
8207 if (txn == NULL || !dbi || dbi >= txn->mt_numdbs || !(txn->mt_dbflags[dbi] & DB_VALID))
8210 txn->mt_dbxs[dbi].md_rel = rel;
8214 int mdb_set_relctx(MDB_txn *txn, MDB_dbi dbi, void *ctx)
8216 if (txn == NULL || !dbi || dbi >= txn->mt_numdbs || !(txn->mt_dbflags[dbi] & DB_VALID))
8219 txn->mt_dbxs[dbi].md_relctx = ctx;
8223 int mdb_env_get_maxkeysize(MDB_env *env)
8225 return MDB_MAXKEYSIZE;
8228 int mdb_reader_list(MDB_env *env, MDB_msg_func *func, void *ctx)
8230 unsigned int i, rdrs;
8237 if (!env->me_txns) {
8238 return func("(no reader locks)\n", ctx);
8240 rdrs = env->me_txns->mti_numreaders;
8241 mr = env->me_txns->mti_readers;
8242 for (i=0; i<rdrs; i++) {
8247 if (mr[i].mr_txnid == (txnid_t)-1) {
8248 sprintf(buf, "%10d %"Z"x -\n", mr[i].mr_pid, tid);
8250 sprintf(buf, "%10d %"Z"x %"Z"u\n", mr[i].mr_pid, tid, mr[i].mr_txnid);
8254 func(" pid thread txnid\n", ctx);
8256 rc = func(buf, ctx);
8262 func("(no active readers)\n", ctx);
8267 /* insert pid into list if not already present.
8268 * return -1 if already present.
8270 static int mdb_pid_insert(pid_t *ids, pid_t pid)
8272 /* binary search of pid in list */
8274 unsigned cursor = 1;
8276 unsigned n = ids[0];
8279 unsigned pivot = n >> 1;
8280 cursor = base + pivot + 1;
8281 val = pid - ids[cursor];
8286 } else if ( val > 0 ) {
8291 /* found, so it's a duplicate */
8300 for (n = ids[0]; n > cursor; n--)
8306 int mdb_reader_check(MDB_env *env, int *dead)
8308 unsigned int i, j, rdrs;
8319 rdrs = env->me_txns->mti_numreaders;
8320 pids = malloc((rdrs+1) * sizeof(pid_t));
8324 mr = env->me_txns->mti_readers;
8326 for (i=0; i<rdrs; i++) {
8327 if (mr[i].mr_pid && mr[i].mr_pid != env->me_pid) {
8329 if (mdb_pid_insert(pids, pid) == 0) {
8330 if (!mdb_reader_pid(env, Pidcheck, pid)) {
8332 /* Recheck, a new process may have reused pid */
8333 if (!mdb_reader_pid(env, Pidcheck, pid)) {
8334 for (j=i; j<rdrs; j++)
8335 if (mr[j].mr_pid == pid) {
8340 UNLOCK_MUTEX_R(env);