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.
36 #include <sys/types.h>
38 #include <sys/param.h>
44 #ifdef HAVE_SYS_FILE_H
61 #if !(defined(BYTE_ORDER) || defined(__BYTE_ORDER))
62 #include <resolv.h> /* defines BYTE_ORDER on HPUX and Solaris */
65 #if defined(__APPLE__) || defined (BSD)
66 # define MDB_USE_POSIX_SEM 1
67 # define MDB_FDATASYNC fsync
68 #elif defined(ANDROID)
69 # define MDB_FDATASYNC fsync
74 #ifdef MDB_USE_POSIX_SEM
75 #include <semaphore.h>
80 #include <valgrind/memcheck.h>
81 #define VGMEMP_CREATE(h,r,z) VALGRIND_CREATE_MEMPOOL(h,r,z)
82 #define VGMEMP_ALLOC(h,a,s) VALGRIND_MEMPOOL_ALLOC(h,a,s)
83 #define VGMEMP_FREE(h,a) VALGRIND_MEMPOOL_FREE(h,a)
84 #define VGMEMP_DESTROY(h) VALGRIND_DESTROY_MEMPOOL(h)
85 #define VGMEMP_DEFINED(a,s) VALGRIND_MAKE_MEM_DEFINED(a,s)
87 #define VGMEMP_CREATE(h,r,z)
88 #define VGMEMP_ALLOC(h,a,s)
89 #define VGMEMP_FREE(h,a)
90 #define VGMEMP_DESTROY(h)
91 #define VGMEMP_DEFINED(a,s)
95 # if (defined(_LITTLE_ENDIAN) || defined(_BIG_ENDIAN)) && !(defined(_LITTLE_ENDIAN) && defined(_BIG_ENDIAN))
96 /* Solaris just defines one or the other */
97 # define LITTLE_ENDIAN 1234
98 # define BIG_ENDIAN 4321
99 # ifdef _LITTLE_ENDIAN
100 # define BYTE_ORDER LITTLE_ENDIAN
102 # define BYTE_ORDER BIG_ENDIAN
105 # define BYTE_ORDER __BYTE_ORDER
109 #ifndef LITTLE_ENDIAN
110 #define LITTLE_ENDIAN __LITTLE_ENDIAN
113 #define BIG_ENDIAN __BIG_ENDIAN
116 #if defined(__i386) || defined(__x86_64)
117 #define MISALIGNED_OK 1
123 #if (BYTE_ORDER == LITTLE_ENDIAN) == (BYTE_ORDER == BIG_ENDIAN)
124 # error "Unknown or unsupported endianness (BYTE_ORDER)"
125 #elif (-6 & 5) || CHAR_BIT != 8 || UINT_MAX < 0xffffffff || ULONG_MAX % 0xFFFF
126 # error "Two's complement, reasonably sized integer types, please"
129 /** @defgroup internal MDB Internals
132 /** @defgroup compat Windows Compatibility Macros
133 * A bunch of macros to minimize the amount of platform-specific ifdefs
134 * needed throughout the rest of the code. When the features this library
135 * needs are similar enough to POSIX to be hidden in a one-or-two line
136 * replacement, this macro approach is used.
140 #define pthread_t DWORD
141 #define pthread_mutex_t HANDLE
142 #define pthread_key_t DWORD
143 #define pthread_self() GetCurrentThreadId()
144 #define pthread_key_create(x,y) \
145 ((*(x) = TlsAlloc()) == TLS_OUT_OF_INDEXES ? ErrCode() : 0)
146 #define pthread_key_delete(x) TlsFree(x)
147 #define pthread_getspecific(x) TlsGetValue(x)
148 #define pthread_setspecific(x,y) (TlsSetValue(x,y) ? 0 : ErrCode())
149 #define pthread_mutex_unlock(x) ReleaseMutex(x)
150 #define pthread_mutex_lock(x) WaitForSingleObject(x, INFINITE)
151 #define LOCK_MUTEX_R(env) pthread_mutex_lock((env)->me_rmutex)
152 #define UNLOCK_MUTEX_R(env) pthread_mutex_unlock((env)->me_rmutex)
153 #define LOCK_MUTEX_W(env) pthread_mutex_lock((env)->me_wmutex)
154 #define UNLOCK_MUTEX_W(env) pthread_mutex_unlock((env)->me_wmutex)
155 #define getpid() GetCurrentProcessId()
156 #define MDB_FDATASYNC(fd) (!FlushFileBuffers(fd))
157 #define MDB_MSYNC(addr,len,flags) (!FlushViewOfFile(addr,len))
158 #define ErrCode() GetLastError()
159 #define GET_PAGESIZE(x) {SYSTEM_INFO si; GetSystemInfo(&si); (x) = si.dwPageSize;}
160 #define close(fd) CloseHandle(fd)
161 #define munmap(ptr,len) UnmapViewOfFile(ptr)
164 #ifdef MDB_USE_POSIX_SEM
166 #define LOCK_MUTEX_R(env) mdb_sem_wait((env)->me_rmutex)
167 #define UNLOCK_MUTEX_R(env) sem_post((env)->me_rmutex)
168 #define LOCK_MUTEX_W(env) mdb_sem_wait((env)->me_wmutex)
169 #define UNLOCK_MUTEX_W(env) sem_post((env)->me_wmutex)
172 mdb_sem_wait(sem_t *sem)
175 while ((rc = sem_wait(sem)) && (rc = errno) == EINTR) ;
180 /** Lock the reader mutex.
182 #define LOCK_MUTEX_R(env) pthread_mutex_lock(&(env)->me_txns->mti_mutex)
183 /** Unlock the reader mutex.
185 #define UNLOCK_MUTEX_R(env) pthread_mutex_unlock(&(env)->me_txns->mti_mutex)
187 /** Lock the writer mutex.
188 * Only a single write transaction is allowed at a time. Other writers
189 * will block waiting for this mutex.
191 #define LOCK_MUTEX_W(env) pthread_mutex_lock(&(env)->me_txns->mti_wmutex)
192 /** Unlock the writer mutex.
194 #define UNLOCK_MUTEX_W(env) pthread_mutex_unlock(&(env)->me_txns->mti_wmutex)
195 #endif /* MDB_USE_POSIX_SEM */
197 /** Get the error code for the last failed system function.
199 #define ErrCode() errno
201 /** An abstraction for a file handle.
202 * On POSIX systems file handles are small integers. On Windows
203 * they're opaque pointers.
207 /** A value for an invalid file handle.
208 * Mainly used to initialize file variables and signify that they are
211 #define INVALID_HANDLE_VALUE (-1)
213 /** Get the size of a memory page for the system.
214 * This is the basic size that the platform's memory manager uses, and is
215 * fundamental to the use of memory-mapped files.
217 #define GET_PAGESIZE(x) ((x) = sysconf(_SC_PAGE_SIZE))
220 #if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
223 #define MNAME_LEN (sizeof(pthread_mutex_t))
229 /** A flag for opening a file and requesting synchronous data writes.
230 * This is only used when writing a meta page. It's not strictly needed;
231 * we could just do a normal write and then immediately perform a flush.
232 * But if this flag is available it saves us an extra system call.
234 * @note If O_DSYNC is undefined but exists in /usr/include,
235 * preferably set some compiler flag to get the definition.
236 * Otherwise compile with the less efficient -DMDB_DSYNC=O_SYNC.
239 # define MDB_DSYNC O_DSYNC
243 /** Function for flushing the data of a file. Define this to fsync
244 * if fdatasync() is not supported.
246 #ifndef MDB_FDATASYNC
247 # define MDB_FDATASYNC fdatasync
251 # define MDB_MSYNC(addr,len,flags) msync(addr,len,flags)
262 /** A page number in the database.
263 * Note that 64 bit page numbers are overkill, since pages themselves
264 * already represent 12-13 bits of addressable memory, and the OS will
265 * always limit applications to a maximum of 63 bits of address space.
267 * @note In the #MDB_node structure, we only store 48 bits of this value,
268 * which thus limits us to only 60 bits of addressable data.
270 typedef MDB_ID pgno_t;
272 /** A transaction ID.
273 * See struct MDB_txn.mt_txnid for details.
275 typedef MDB_ID txnid_t;
277 /** @defgroup debug Debug Macros
281 /** Enable debug output.
282 * Set this to 1 for copious tracing. Set to 2 to add dumps of all IDLs
283 * read from and written to the database (used for free space management).
288 #if !(__STDC_VERSION__ >= 199901L || defined(__GNUC__))
291 # define DPRINTF (void) /* Vararg macros may be unsupported */
293 static int mdb_debug;
294 static txnid_t mdb_debug_start;
296 /** Print a debug message with printf formatting. */
297 # define DPRINTF(fmt, ...) /**< Requires 2 or more args */ \
298 ((void) ((mdb_debug) && \
299 fprintf(stderr, "%s:%d " fmt "\n", __func__, __LINE__, __VA_ARGS__)))
301 # define DPRINTF(fmt, ...) ((void) 0)
302 # define MDB_DEBUG_SKIP
304 /** Print a debug string.
305 * The string is printed literally, with no format processing.
307 #define DPUTS(arg) DPRINTF("%s", arg)
310 /** A default memory page size.
311 * The actual size is platform-dependent, but we use this for
312 * boot-strapping. We probably should not be using this any more.
313 * The #GET_PAGESIZE() macro is used to get the actual size.
315 * Note that we don't currently support Huge pages. On Linux,
316 * regular data files cannot use Huge pages, and in general
317 * Huge pages aren't actually pageable. We rely on the OS
318 * demand-pager to read our data and page it out when memory
319 * pressure from other processes is high. So until OSs have
320 * actual paging support for Huge pages, they're not viable.
322 #define MDB_PAGESIZE 4096
324 /** The minimum number of keys required in a database page.
325 * Setting this to a larger value will place a smaller bound on the
326 * maximum size of a data item. Data items larger than this size will
327 * be pushed into overflow pages instead of being stored directly in
328 * the B-tree node. This value used to default to 4. With a page size
329 * of 4096 bytes that meant that any item larger than 1024 bytes would
330 * go into an overflow page. That also meant that on average 2-3KB of
331 * each overflow page was wasted space. The value cannot be lower than
332 * 2 because then there would no longer be a tree structure. With this
333 * value, items larger than 2KB will go into overflow pages, and on
334 * average only 1KB will be wasted.
336 #define MDB_MINKEYS 2
338 /** A stamp that identifies a file as an MDB file.
339 * There's nothing special about this value other than that it is easily
340 * recognizable, and it will reflect any byte order mismatches.
342 #define MDB_MAGIC 0xBEEFC0DE
344 /** The version number for a database's file format. */
345 #define MDB_VERSION 1
347 /** @brief The maximum size of a key in the database.
349 * We require that keys all fit onto a regular page. This limit
350 * could be raised a bit further if needed; to something just
351 * under #MDB_PAGESIZE / #MDB_MINKEYS.
353 * Note that data items in an #MDB_DUPSORT database are actually keys
354 * of a subDB, so they're also limited to this size.
356 #ifndef MDB_MAXKEYSIZE
357 #define MDB_MAXKEYSIZE 511
360 /** @brief The maximum size of a data item.
362 * We only store a 32 bit value for node sizes.
364 #define MAXDATASIZE 0xffffffffUL
369 * This is used for printing a hex dump of a key's contents.
371 #define DKBUF char kbuf[(MDB_MAXKEYSIZE*2+1)]
372 /** Display a key in hex.
374 * Invoke a function to display a key in hex.
376 #define DKEY(x) mdb_dkey(x, kbuf)
378 #define DKBUF typedef int dummy_kbuf /* so we can put ';' after */
382 /** An invalid page number.
383 * Mainly used to denote an empty tree.
385 #define P_INVALID (~(pgno_t)0)
387 /** Test if the flags \b f are set in a flag word \b w. */
388 #define F_ISSET(w, f) (((w) & (f)) == (f))
390 /** Used for offsets within a single page.
391 * Since memory pages are typically 4 or 8KB in size, 12-13 bits,
394 typedef uint16_t indx_t;
396 /** Default size of memory map.
397 * This is certainly too small for any actual applications. Apps should always set
398 * the size explicitly using #mdb_env_set_mapsize().
400 #define DEFAULT_MAPSIZE 1048576
402 /** @defgroup readers Reader Lock Table
403 * Readers don't acquire any locks for their data access. Instead, they
404 * simply record their transaction ID in the reader table. The reader
405 * mutex is needed just to find an empty slot in the reader table. The
406 * slot's address is saved in thread-specific data so that subsequent read
407 * transactions started by the same thread need no further locking to proceed.
409 * If #MDB_NOTLS is set, the slot address is not saved in thread-specific data.
411 * No reader table is used if the database is on a read-only filesystem.
413 * Since the database uses multi-version concurrency control, readers don't
414 * actually need any locking. This table is used to keep track of which
415 * readers are using data from which old transactions, so that we'll know
416 * when a particular old transaction is no longer in use. Old transactions
417 * that have discarded any data pages can then have those pages reclaimed
418 * for use by a later write transaction.
420 * The lock table is constructed such that reader slots are aligned with the
421 * processor's cache line size. Any slot is only ever used by one thread.
422 * This alignment guarantees that there will be no contention or cache
423 * thrashing as threads update their own slot info, and also eliminates
424 * any need for locking when accessing a slot.
426 * A writer thread will scan every slot in the table to determine the oldest
427 * outstanding reader transaction. Any freed pages older than this will be
428 * reclaimed by the writer. The writer doesn't use any locks when scanning
429 * this table. This means that there's no guarantee that the writer will
430 * see the most up-to-date reader info, but that's not required for correct
431 * operation - all we need is to know the upper bound on the oldest reader,
432 * we don't care at all about the newest reader. So the only consequence of
433 * reading stale information here is that old pages might hang around a
434 * while longer before being reclaimed. That's actually good anyway, because
435 * the longer we delay reclaiming old pages, the more likely it is that a
436 * string of contiguous pages can be found after coalescing old pages from
437 * many old transactions together.
440 /** Number of slots in the reader table.
441 * This value was chosen somewhat arbitrarily. 126 readers plus a
442 * couple mutexes fit exactly into 8KB on my development machine.
443 * Applications should set the table size using #mdb_env_set_maxreaders().
445 #define DEFAULT_READERS 126
447 /** The size of a CPU cache line in bytes. We want our lock structures
448 * aligned to this size to avoid false cache line sharing in the
450 * This value works for most CPUs. For Itanium this should be 128.
456 /** The information we store in a single slot of the reader table.
457 * In addition to a transaction ID, we also record the process and
458 * thread ID that owns a slot, so that we can detect stale information,
459 * e.g. threads or processes that went away without cleaning up.
460 * @note We currently don't check for stale records. We simply re-init
461 * the table when we know that we're the only process opening the
464 typedef struct MDB_rxbody {
465 /** Current Transaction ID when this transaction began, or (txnid_t)-1.
466 * Multiple readers that start at the same time will probably have the
467 * same ID here. Again, it's not important to exclude them from
468 * anything; all we need to know is which version of the DB they
469 * started from so we can avoid overwriting any data used in that
470 * particular version.
473 /** The process ID of the process owning this reader txn. */
475 /** The thread ID of the thread owning this txn. */
479 /** The actual reader record, with cacheline padding. */
480 typedef struct MDB_reader {
483 /** shorthand for mrb_txnid */
484 #define mr_txnid mru.mrx.mrb_txnid
485 #define mr_pid mru.mrx.mrb_pid
486 #define mr_tid mru.mrx.mrb_tid
487 /** cache line alignment */
488 char pad[(sizeof(MDB_rxbody)+CACHELINE-1) & ~(CACHELINE-1)];
492 /** The header for the reader table.
493 * The table resides in a memory-mapped file. (This is a different file
494 * than is used for the main database.)
496 * For POSIX the actual mutexes reside in the shared memory of this
497 * mapped file. On Windows, mutexes are named objects allocated by the
498 * kernel; we store the mutex names in this mapped file so that other
499 * processes can grab them. This same approach is also used on
500 * MacOSX/Darwin (using named semaphores) since MacOSX doesn't support
501 * process-shared POSIX mutexes. For these cases where a named object
502 * is used, the object name is derived from a 64 bit FNV hash of the
503 * environment pathname. As such, naming collisions are extremely
504 * unlikely. If a collision occurs, the results are unpredictable.
506 typedef struct MDB_txbody {
507 /** Stamp identifying this as an MDB file. It must be set
510 /** Version number of this lock file. Must be set to #MDB_VERSION. */
511 uint32_t mtb_version;
512 #if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
513 char mtb_rmname[MNAME_LEN];
515 /** Mutex protecting access to this table.
516 * This is the reader lock that #LOCK_MUTEX_R acquires.
518 pthread_mutex_t mtb_mutex;
520 /** The ID of the last transaction committed to the database.
521 * This is recorded here only for convenience; the value can always
522 * be determined by reading the main database meta pages.
525 /** The number of slots that have been used in the reader table.
526 * This always records the maximum count, it is not decremented
527 * when readers release their slots.
529 unsigned mtb_numreaders;
532 /** The actual reader table definition. */
533 typedef struct MDB_txninfo {
536 #define mti_magic mt1.mtb.mtb_magic
537 #define mti_version mt1.mtb.mtb_version
538 #define mti_mutex mt1.mtb.mtb_mutex
539 #define mti_rmname mt1.mtb.mtb_rmname
540 #define mti_txnid mt1.mtb.mtb_txnid
541 #define mti_numreaders mt1.mtb.mtb_numreaders
542 char pad[(sizeof(MDB_txbody)+CACHELINE-1) & ~(CACHELINE-1)];
545 #if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
546 char mt2_wmname[MNAME_LEN];
547 #define mti_wmname mt2.mt2_wmname
549 pthread_mutex_t mt2_wmutex;
550 #define mti_wmutex mt2.mt2_wmutex
552 char pad[(MNAME_LEN+CACHELINE-1) & ~(CACHELINE-1)];
554 MDB_reader mti_readers[1];
558 /** Common header for all page types.
559 * Overflow records occupy a number of contiguous pages with no
560 * headers on any page after the first.
562 typedef struct MDB_page {
563 #define mp_pgno mp_p.p_pgno
564 #define mp_next mp_p.p_next
566 pgno_t p_pgno; /**< page number */
567 void * p_next; /**< for in-memory list of freed structs */
570 /** @defgroup mdb_page Page Flags
572 * Flags for the page headers.
575 #define P_BRANCH 0x01 /**< branch page */
576 #define P_LEAF 0x02 /**< leaf page */
577 #define P_OVERFLOW 0x04 /**< overflow page */
578 #define P_META 0x08 /**< meta page */
579 #define P_DIRTY 0x10 /**< dirty page */
580 #define P_LEAF2 0x20 /**< for #MDB_DUPFIXED records */
581 #define P_SUBP 0x40 /**< for #MDB_DUPSORT sub-pages */
583 uint16_t mp_flags; /**< @ref mdb_page */
584 #define mp_lower mp_pb.pb.pb_lower
585 #define mp_upper mp_pb.pb.pb_upper
586 #define mp_pages mp_pb.pb_pages
589 indx_t pb_lower; /**< lower bound of free space */
590 indx_t pb_upper; /**< upper bound of free space */
592 uint32_t pb_pages; /**< number of overflow pages */
594 indx_t mp_ptrs[1]; /**< dynamic size */
597 /** Size of the page header, excluding dynamic data at the end */
598 #define PAGEHDRSZ ((unsigned) offsetof(MDB_page, mp_ptrs))
600 /** Address of first usable data byte in a page, after the header */
601 #define METADATA(p) ((void *)((char *)(p) + PAGEHDRSZ))
603 /** Number of nodes on a page */
604 #define NUMKEYS(p) (((p)->mp_lower - PAGEHDRSZ) >> 1)
606 /** The amount of space remaining in the page */
607 #define SIZELEFT(p) (indx_t)((p)->mp_upper - (p)->mp_lower)
609 /** The percentage of space used in the page, in tenths of a percent. */
610 #define PAGEFILL(env, p) (1000L * ((env)->me_psize - PAGEHDRSZ - SIZELEFT(p)) / \
611 ((env)->me_psize - PAGEHDRSZ))
612 /** The minimum page fill factor, in tenths of a percent.
613 * Pages emptier than this are candidates for merging.
615 #define FILL_THRESHOLD 250
617 /** Test if a page is a leaf page */
618 #define IS_LEAF(p) F_ISSET((p)->mp_flags, P_LEAF)
619 /** Test if a page is a LEAF2 page */
620 #define IS_LEAF2(p) F_ISSET((p)->mp_flags, P_LEAF2)
621 /** Test if a page is a branch page */
622 #define IS_BRANCH(p) F_ISSET((p)->mp_flags, P_BRANCH)
623 /** Test if a page is an overflow page */
624 #define IS_OVERFLOW(p) F_ISSET((p)->mp_flags, P_OVERFLOW)
625 /** Test if a page is a sub page */
626 #define IS_SUBP(p) F_ISSET((p)->mp_flags, P_SUBP)
628 /** The number of overflow pages needed to store the given size. */
629 #define OVPAGES(size, psize) ((PAGEHDRSZ-1 + (size)) / (psize) + 1)
631 /** Header for a single key/data pair within a page.
632 * We guarantee 2-byte alignment for nodes.
634 typedef struct MDB_node {
635 /** lo and hi are used for data size on leaf nodes and for
636 * child pgno on branch nodes. On 64 bit platforms, flags
637 * is also used for pgno. (Branch nodes have no flags).
638 * They are in host byte order in case that lets some
639 * accesses be optimized into a 32-bit word access.
641 #define mn_lo mn_offset[BYTE_ORDER!=LITTLE_ENDIAN]
642 #define mn_hi mn_offset[BYTE_ORDER==LITTLE_ENDIAN] /**< part of dsize or pgno */
643 unsigned short mn_offset[2]; /**< storage for #mn_lo and #mn_hi */
644 /** @defgroup mdb_node Node Flags
646 * Flags for node headers.
649 #define F_BIGDATA 0x01 /**< data put on overflow page */
650 #define F_SUBDATA 0x02 /**< data is a sub-database */
651 #define F_DUPDATA 0x04 /**< data has duplicates */
653 /** valid flags for #mdb_node_add() */
654 #define NODE_ADD_FLAGS (F_DUPDATA|F_SUBDATA|MDB_RESERVE|MDB_APPEND)
657 unsigned short mn_flags; /**< @ref mdb_node */
658 unsigned short mn_ksize; /**< key size */
659 char mn_data[1]; /**< key and data are appended here */
662 /** Size of the node header, excluding dynamic data at the end */
663 #define NODESIZE offsetof(MDB_node, mn_data)
665 /** Bit position of top word in page number, for shifting mn_flags */
666 #define PGNO_TOPWORD ((pgno_t)-1 > 0xffffffffu ? 32 : 0)
668 /** Size of a node in a branch page with a given key.
669 * This is just the node header plus the key, there is no data.
671 #define INDXSIZE(k) (NODESIZE + ((k) == NULL ? 0 : (k)->mv_size))
673 /** Size of a node in a leaf page with a given key and data.
674 * This is node header plus key plus data size.
676 #define LEAFSIZE(k, d) (NODESIZE + (k)->mv_size + (d)->mv_size)
678 /** Address of node \b i in page \b p */
679 #define NODEPTR(p, i) ((MDB_node *)((char *)(p) + (p)->mp_ptrs[i]))
681 /** Address of the key for the node */
682 #define NODEKEY(node) (void *)((node)->mn_data)
684 /** Address of the data for a node */
685 #define NODEDATA(node) (void *)((char *)(node)->mn_data + (node)->mn_ksize)
687 /** Get the page number pointed to by a branch node */
688 #define NODEPGNO(node) \
689 ((node)->mn_lo | ((pgno_t) (node)->mn_hi << 16) | \
690 (PGNO_TOPWORD ? ((pgno_t) (node)->mn_flags << PGNO_TOPWORD) : 0))
691 /** Set the page number in a branch node */
692 #define SETPGNO(node,pgno) do { \
693 (node)->mn_lo = (pgno) & 0xffff; (node)->mn_hi = (pgno) >> 16; \
694 if (PGNO_TOPWORD) (node)->mn_flags = (pgno) >> PGNO_TOPWORD; } while(0)
696 /** Get the size of the data in a leaf node */
697 #define NODEDSZ(node) ((node)->mn_lo | ((unsigned)(node)->mn_hi << 16))
698 /** Set the size of the data for a leaf node */
699 #define SETDSZ(node,size) do { \
700 (node)->mn_lo = (size) & 0xffff; (node)->mn_hi = (size) >> 16;} while(0)
701 /** The size of a key in a node */
702 #define NODEKSZ(node) ((node)->mn_ksize)
704 /** Copy a page number from src to dst */
706 #define COPY_PGNO(dst,src) dst = src
708 #if SIZE_MAX > 4294967295UL
709 #define COPY_PGNO(dst,src) do { \
710 unsigned short *s, *d; \
711 s = (unsigned short *)&(src); \
712 d = (unsigned short *)&(dst); \
719 #define COPY_PGNO(dst,src) do { \
720 unsigned short *s, *d; \
721 s = (unsigned short *)&(src); \
722 d = (unsigned short *)&(dst); \
728 /** The address of a key in a LEAF2 page.
729 * LEAF2 pages are used for #MDB_DUPFIXED sorted-duplicate sub-DBs.
730 * There are no node headers, keys are stored contiguously.
732 #define LEAF2KEY(p, i, ks) ((char *)(p) + PAGEHDRSZ + ((i)*(ks)))
734 /** Set the \b node's key into \b key, if requested. */
735 #define MDB_GET_KEY(node, key) { if ((key) != NULL) { \
736 (key)->mv_size = NODEKSZ(node); (key)->mv_data = NODEKEY(node); } }
738 /** Information about a single database in the environment. */
739 typedef struct MDB_db {
740 uint32_t md_pad; /**< also ksize for LEAF2 pages */
741 uint16_t md_flags; /**< @ref mdb_dbi_open */
742 uint16_t md_depth; /**< depth of this tree */
743 pgno_t md_branch_pages; /**< number of internal pages */
744 pgno_t md_leaf_pages; /**< number of leaf pages */
745 pgno_t md_overflow_pages; /**< number of overflow pages */
746 size_t md_entries; /**< number of data items */
747 pgno_t md_root; /**< the root page of this tree */
750 /** mdb_dbi_open flags */
751 #define MDB_VALID 0x8000 /**< DB handle is valid, for me_dbflags */
752 #define PERSISTENT_FLAGS (0xffff & ~(MDB_VALID))
753 #define VALID_FLAGS (MDB_REVERSEKEY|MDB_DUPSORT|MDB_INTEGERKEY|MDB_DUPFIXED|\
754 MDB_INTEGERDUP|MDB_REVERSEDUP|MDB_CREATE)
756 /** Handle for the DB used to track free pages. */
758 /** Handle for the default DB. */
761 /** Meta page content. */
762 typedef struct MDB_meta {
763 /** Stamp identifying this as an MDB file. It must be set
766 /** Version number of this lock file. Must be set to #MDB_VERSION. */
768 void *mm_address; /**< address for fixed mapping */
769 size_t mm_mapsize; /**< size of mmap region */
770 MDB_db mm_dbs[2]; /**< first is free space, 2nd is main db */
771 /** The size of pages used in this DB */
772 #define mm_psize mm_dbs[0].md_pad
773 /** Any persistent environment flags. @ref mdb_env */
774 #define mm_flags mm_dbs[0].md_flags
775 pgno_t mm_last_pg; /**< last used page in file */
776 txnid_t mm_txnid; /**< txnid that committed this page */
779 /** Buffer for a stack-allocated dirty page.
780 * The members define size and alignment, and silence type
781 * aliasing warnings. They are not used directly; that could
782 * mean incorrectly using several union members in parallel.
784 typedef union MDB_pagebuf {
785 char mb_raw[MDB_PAGESIZE];
788 char mm_pad[PAGEHDRSZ];
793 /** Auxiliary DB info.
794 * The information here is mostly static/read-only. There is
795 * only a single copy of this record in the environment.
797 typedef struct MDB_dbx {
798 MDB_val md_name; /**< name of the database */
799 MDB_cmp_func *md_cmp; /**< function for comparing keys */
800 MDB_cmp_func *md_dcmp; /**< function for comparing data items */
801 MDB_rel_func *md_rel; /**< user relocate function */
802 void *md_relctx; /**< user-provided context for md_rel */
805 /** A database transaction.
806 * Every operation requires a transaction handle.
809 MDB_txn *mt_parent; /**< parent of a nested txn */
810 MDB_txn *mt_child; /**< nested txn under this txn */
811 pgno_t mt_next_pgno; /**< next unallocated page */
812 /** The ID of this transaction. IDs are integers incrementing from 1.
813 * Only committed write transactions increment the ID. If a transaction
814 * aborts, the ID may be re-used by the next writer.
817 MDB_env *mt_env; /**< the DB environment */
818 /** The list of pages that became unused during this transaction.
822 MDB_ID2L dirty_list; /**< for write txns: modified pages */
823 MDB_reader *reader; /**< this thread's reader table slot or NULL */
825 /** Array of records for each DB known in the environment. */
827 /** Array of MDB_db records for each known DB */
829 /** @defgroup mt_dbflag Transaction DB Flags
833 #define DB_DIRTY 0x01 /**< DB was written in this txn */
834 #define DB_STALE 0x02 /**< DB record is older than txnID */
835 #define DB_NEW 0x04 /**< DB handle opened in this txn */
836 #define DB_VALID 0x08 /**< DB handle is valid, see also #MDB_VALID */
838 /** In write txns, array of cursors for each DB */
839 MDB_cursor **mt_cursors;
840 /** Array of flags for each DB */
841 unsigned char *mt_dbflags;
842 /** Number of DB records in use. This number only ever increments;
843 * we don't decrement it when individual DB handles are closed.
847 /** @defgroup mdb_txn Transaction Flags
851 #define MDB_TXN_RDONLY 0x01 /**< read-only transaction */
852 #define MDB_TXN_ERROR 0x02 /**< an error has occurred */
853 #define MDB_TXN_DIRTY 0x04 /**< must write, even if dirty list is empty */
855 unsigned int mt_flags; /**< @ref mdb_txn */
856 /** dirty_list maxsize - #allocated pages including in parent txns */
857 unsigned int mt_dirty_room;
858 /** Tracks which of the two meta pages was used at the start
859 * of this transaction.
861 unsigned int mt_toggle;
864 /** Enough space for 2^32 nodes with minimum of 2 keys per node. I.e., plenty.
865 * At 4 keys per node, enough for 2^64 nodes, so there's probably no need to
866 * raise this on a 64 bit machine.
868 #define CURSOR_STACK 32
872 /** Cursors are used for all DB operations */
874 /** Next cursor on this DB in this txn */
876 /** Original cursor if this is a shadow */
878 /** Context used for databases with #MDB_DUPSORT, otherwise NULL */
879 struct MDB_xcursor *mc_xcursor;
880 /** The transaction that owns this cursor */
882 /** The database handle this cursor operates on */
884 /** The database record for this cursor */
886 /** The database auxiliary record for this cursor */
888 /** The @ref mt_dbflag for this database */
889 unsigned char *mc_dbflag;
890 unsigned short mc_snum; /**< number of pushed pages */
891 unsigned short mc_top; /**< index of top page, normally mc_snum-1 */
892 /** @defgroup mdb_cursor Cursor Flags
894 * Cursor state flags.
897 #define C_INITIALIZED 0x01 /**< cursor has been initialized and is valid */
898 #define C_EOF 0x02 /**< No more data */
899 #define C_SUB 0x04 /**< Cursor is a sub-cursor */
900 #define C_SHADOW 0x08 /**< Cursor is a dup from a parent txn */
901 #define C_ALLOCD 0x10 /**< Cursor was malloc'd */
902 #define C_SPLITTING 0x20 /**< Cursor is in page_split */
903 #define C_UNTRACK 0x40 /**< Un-track cursor when closing */
905 unsigned int mc_flags; /**< @ref mdb_cursor */
906 MDB_page *mc_pg[CURSOR_STACK]; /**< stack of pushed pages */
907 indx_t mc_ki[CURSOR_STACK]; /**< stack of page indices */
910 /** Context for sorted-dup records.
911 * We could have gone to a fully recursive design, with arbitrarily
912 * deep nesting of sub-databases. But for now we only handle these
913 * levels - main DB, optional sub-DB, sorted-duplicate DB.
915 typedef struct MDB_xcursor {
916 /** A sub-cursor for traversing the Dup DB */
917 MDB_cursor mx_cursor;
918 /** The database record for this Dup DB */
920 /** The auxiliary DB record for this Dup DB */
922 /** The @ref mt_dbflag for this Dup DB */
923 unsigned char mx_dbflag;
926 /** State of FreeDB old pages, stored in the MDB_env */
927 typedef struct MDB_pgstate {
928 txnid_t mf_pglast; /**< ID of last old page record we used */
929 pgno_t *mf_pghead; /**< old pages reclaimed from freelist */
930 pgno_t *mf_pgfree; /**< memory to free when dropping me_pghead */
933 /** The database environment. */
935 HANDLE me_fd; /**< The main data file */
936 HANDLE me_lfd; /**< The lock file */
937 HANDLE me_mfd; /**< just for writing the meta pages */
938 /** Failed to update the meta page. Probably an I/O error. */
939 #define MDB_FATAL_ERROR 0x80000000U
940 /** Some fields are initialized. */
941 #define MDB_ENV_ACTIVE 0x20000000U
942 /** me_txkey is set */
943 #define MDB_ENV_TXKEY 0x10000000U
944 uint32_t me_flags; /**< @ref mdb_env */
945 unsigned int me_psize; /**< size of a page, from #GET_PAGESIZE */
946 unsigned int me_maxreaders; /**< size of the reader table */
947 unsigned int me_numreaders; /**< max numreaders set by this env */
948 MDB_dbi me_numdbs; /**< number of DBs opened */
949 MDB_dbi me_maxdbs; /**< size of the DB table */
950 pid_t me_pid; /**< process ID of this env */
951 char *me_path; /**< path to the DB files */
952 char *me_map; /**< the memory map of the data file */
953 MDB_txninfo *me_txns; /**< the memory map of the lock file or NULL */
954 MDB_meta *me_metas[2]; /**< pointers to the two meta pages */
955 MDB_txn *me_txn; /**< current write transaction */
956 size_t me_mapsize; /**< size of the data memory map */
957 off_t me_size; /**< current file size */
958 pgno_t me_maxpg; /**< me_mapsize / me_psize */
959 MDB_dbx *me_dbxs; /**< array of static DB info */
960 uint16_t *me_dbflags; /**< array of flags from MDB_db.md_flags */
961 pthread_key_t me_txkey; /**< thread-key for readers */
962 MDB_pgstate me_pgstate; /**< state of old pages from freeDB */
963 # define me_pglast me_pgstate.mf_pglast
964 # define me_pghead me_pgstate.mf_pghead
965 # define me_pgfree me_pgstate.mf_pgfree
966 MDB_page *me_dpages; /**< list of malloc'd blocks for re-use */
967 /** IDL of pages that became unused in a write txn */
969 /** ID2L of pages written during a write txn. Length MDB_IDL_UM_SIZE. */
970 MDB_ID2L me_dirty_list;
971 /** Max number of freelist items that can fit in a single overflow page */
972 unsigned int me_maxfree_1pg;
973 /** Max size of a node on a page */
974 unsigned int me_nodemax;
976 HANDLE me_rmutex; /* Windows mutexes don't reside in shared mem */
978 #elif defined(MDB_USE_POSIX_SEM)
979 sem_t *me_rmutex; /* Shared mutexes are not supported */
984 /** Nested transaction */
985 typedef struct MDB_ntxn {
986 MDB_txn mnt_txn; /* the transaction */
987 MDB_pgstate mnt_pgstate; /* parent transaction's saved freestate */
990 /** max number of pages to commit in one writev() call */
991 #define MDB_COMMIT_PAGES 64
992 #if defined(IOV_MAX) && IOV_MAX < MDB_COMMIT_PAGES
993 #undef MDB_COMMIT_PAGES
994 #define MDB_COMMIT_PAGES IOV_MAX
997 static int mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp);
998 static int mdb_page_new(MDB_cursor *mc, uint32_t flags, int num, MDB_page **mp);
999 static int mdb_page_touch(MDB_cursor *mc);
1001 static int mdb_page_get(MDB_txn *txn, pgno_t pgno, MDB_page **mp);
1002 static int mdb_page_search_root(MDB_cursor *mc,
1003 MDB_val *key, int modify);
1004 #define MDB_PS_MODIFY 1
1005 #define MDB_PS_ROOTONLY 2
1006 static int mdb_page_search(MDB_cursor *mc,
1007 MDB_val *key, int flags);
1008 static int mdb_page_merge(MDB_cursor *csrc, MDB_cursor *cdst);
1010 #define MDB_SPLIT_REPLACE MDB_APPENDDUP /**< newkey is not new */
1011 static int mdb_page_split(MDB_cursor *mc, MDB_val *newkey, MDB_val *newdata,
1012 pgno_t newpgno, unsigned int nflags);
1014 static int mdb_env_read_header(MDB_env *env, MDB_meta *meta);
1015 static int mdb_env_pick_meta(const MDB_env *env);
1016 static int mdb_env_write_meta(MDB_txn *txn);
1017 static void mdb_env_close0(MDB_env *env, int excl);
1019 static MDB_node *mdb_node_search(MDB_cursor *mc, MDB_val *key, int *exactp);
1020 static int mdb_node_add(MDB_cursor *mc, indx_t indx,
1021 MDB_val *key, MDB_val *data, pgno_t pgno, unsigned int flags);
1022 static void mdb_node_del(MDB_page *mp, indx_t indx, int ksize);
1023 static void mdb_node_shrink(MDB_page *mp, indx_t indx);
1024 static int mdb_node_move(MDB_cursor *csrc, MDB_cursor *cdst);
1025 static int mdb_node_read(MDB_txn *txn, MDB_node *leaf, MDB_val *data);
1026 static size_t mdb_leaf_size(MDB_env *env, MDB_val *key, MDB_val *data);
1027 static size_t mdb_branch_size(MDB_env *env, MDB_val *key);
1029 static int mdb_rebalance(MDB_cursor *mc);
1030 static int mdb_update_key(MDB_cursor *mc, MDB_val *key);
1032 static void mdb_cursor_pop(MDB_cursor *mc);
1033 static int mdb_cursor_push(MDB_cursor *mc, MDB_page *mp);
1035 static int mdb_cursor_del0(MDB_cursor *mc, MDB_node *leaf);
1036 static int mdb_cursor_sibling(MDB_cursor *mc, int move_right);
1037 static int mdb_cursor_next(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op);
1038 static int mdb_cursor_prev(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op);
1039 static int mdb_cursor_set(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op,
1041 static int mdb_cursor_first(MDB_cursor *mc, MDB_val *key, MDB_val *data);
1042 static int mdb_cursor_last(MDB_cursor *mc, MDB_val *key, MDB_val *data);
1044 static void mdb_cursor_init(MDB_cursor *mc, MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx);
1045 static void mdb_xcursor_init0(MDB_cursor *mc);
1046 static void mdb_xcursor_init1(MDB_cursor *mc, MDB_node *node);
1048 static int mdb_drop0(MDB_cursor *mc, int subs);
1049 static void mdb_default_cmp(MDB_txn *txn, MDB_dbi dbi);
1052 static MDB_cmp_func mdb_cmp_memn, mdb_cmp_memnr, mdb_cmp_int, mdb_cmp_cint, mdb_cmp_long;
1056 static SECURITY_DESCRIPTOR mdb_null_sd;
1057 static SECURITY_ATTRIBUTES mdb_all_sa;
1058 static int mdb_sec_inited;
1061 /** Return the library version info. */
1063 mdb_version(int *major, int *minor, int *patch)
1065 if (major) *major = MDB_VERSION_MAJOR;
1066 if (minor) *minor = MDB_VERSION_MINOR;
1067 if (patch) *patch = MDB_VERSION_PATCH;
1068 return MDB_VERSION_STRING;
1071 /** Table of descriptions for MDB @ref errors */
1072 static char *const mdb_errstr[] = {
1073 "MDB_KEYEXIST: Key/data pair already exists",
1074 "MDB_NOTFOUND: No matching key/data pair found",
1075 "MDB_PAGE_NOTFOUND: Requested page not found",
1076 "MDB_CORRUPTED: Located page was wrong type",
1077 "MDB_PANIC: Update of meta page failed",
1078 "MDB_VERSION_MISMATCH: Database environment version mismatch",
1079 "MDB_INVALID: File is not an MDB file",
1080 "MDB_MAP_FULL: Environment mapsize limit reached",
1081 "MDB_DBS_FULL: Environment maxdbs limit reached",
1082 "MDB_READERS_FULL: Environment maxreaders limit reached",
1083 "MDB_TLS_FULL: Thread-local storage keys full - too many environments open",
1084 "MDB_TXN_FULL: Transaction has too many dirty pages - transaction too big",
1085 "MDB_CURSOR_FULL: Internal error - cursor stack limit reached",
1086 "MDB_PAGE_FULL: Internal error - page has no more space",
1087 "MDB_MAP_RESIZED: Database contents grew beyond environment mapsize",
1088 "MDB_INCOMPATIBLE: Database flags changed or would change",
1089 "MDB_BAD_RSLOT: Invalid reuse of reader locktable slot",
1093 mdb_strerror(int err)
1097 return ("Successful return: 0");
1099 if (err >= MDB_KEYEXIST && err <= MDB_LAST_ERRCODE) {
1100 i = err - MDB_KEYEXIST;
1101 return mdb_errstr[i];
1104 return strerror(err);
1108 /** Display a key in hexadecimal and return the address of the result.
1109 * @param[in] key the key to display
1110 * @param[in] buf the buffer to write into. Should always be #DKBUF.
1111 * @return The key in hexadecimal form.
1114 mdb_dkey(MDB_val *key, char *buf)
1117 unsigned char *c = key->mv_data;
1123 if (key->mv_size > MDB_MAXKEYSIZE)
1124 return "MDB_MAXKEYSIZE";
1125 /* may want to make this a dynamic check: if the key is mostly
1126 * printable characters, print it as-is instead of converting to hex.
1130 for (i=0; i<key->mv_size; i++)
1131 ptr += sprintf(ptr, "%02x", *c++);
1133 sprintf(buf, "%.*s", key->mv_size, key->mv_data);
1138 /** Display all the keys in the page. */
1140 mdb_page_list(MDB_page *mp)
1143 unsigned int i, nkeys, nsize;
1147 nkeys = NUMKEYS(mp);
1148 fprintf(stderr, "Page %zu numkeys %d\n", mp->mp_pgno, nkeys);
1149 for (i=0; i<nkeys; i++) {
1150 node = NODEPTR(mp, i);
1151 key.mv_size = node->mn_ksize;
1152 key.mv_data = node->mn_data;
1153 nsize = NODESIZE + NODEKSZ(node) + sizeof(indx_t);
1154 if (IS_BRANCH(mp)) {
1155 fprintf(stderr, "key %d: page %zu, %s\n", i, NODEPGNO(node),
1158 if (F_ISSET(node->mn_flags, F_BIGDATA))
1159 nsize += sizeof(pgno_t);
1161 nsize += NODEDSZ(node);
1162 fprintf(stderr, "key %d: nsize %d, %s\n", i, nsize, DKEY(&key));
1168 mdb_cursor_chk(MDB_cursor *mc)
1174 if (!mc->mc_snum && !(mc->mc_flags & C_INITIALIZED)) return;
1175 for (i=0; i<mc->mc_top; i++) {
1177 node = NODEPTR(mp, mc->mc_ki[i]);
1178 if (NODEPGNO(node) != mc->mc_pg[i+1]->mp_pgno)
1181 if (mc->mc_ki[i] >= NUMKEYS(mc->mc_pg[i]))
1187 /** Count all the pages in each DB and in the freelist
1188 * and make sure it matches the actual number of pages
1191 static void mdb_audit(MDB_txn *txn)
1195 MDB_ID freecount, count;
1200 mdb_cursor_init(&mc, txn, FREE_DBI, NULL);
1201 while ((rc = mdb_cursor_get(&mc, &key, &data, MDB_NEXT)) == 0)
1202 freecount += *(MDB_ID *)data.mv_data;
1205 for (i = 0; i<txn->mt_numdbs; i++) {
1206 MDB_xcursor mx, *mxp;
1207 mxp = (txn->mt_dbs[i].md_flags & MDB_DUPSORT) ? &mx : NULL;
1208 mdb_cursor_init(&mc, txn, i, mxp);
1209 if (txn->mt_dbs[i].md_root == P_INVALID)
1211 count += txn->mt_dbs[i].md_branch_pages +
1212 txn->mt_dbs[i].md_leaf_pages +
1213 txn->mt_dbs[i].md_overflow_pages;
1214 if (txn->mt_dbs[i].md_flags & MDB_DUPSORT) {
1215 mdb_page_search(&mc, NULL, 0);
1219 mp = mc.mc_pg[mc.mc_top];
1220 for (j=0; j<NUMKEYS(mp); j++) {
1221 MDB_node *leaf = NODEPTR(mp, j);
1222 if (leaf->mn_flags & F_SUBDATA) {
1224 memcpy(&db, NODEDATA(leaf), sizeof(db));
1225 count += db.md_branch_pages + db.md_leaf_pages +
1226 db.md_overflow_pages;
1230 while (mdb_cursor_sibling(&mc, 1) == 0);
1233 if (freecount + count + 2 /* metapages */ != txn->mt_next_pgno) {
1234 fprintf(stderr, "audit: %lu freecount: %lu count: %lu total: %lu next_pgno: %lu\n",
1235 txn->mt_txnid, freecount, count+2, freecount+count+2, txn->mt_next_pgno);
1241 mdb_cmp(MDB_txn *txn, MDB_dbi dbi, const MDB_val *a, const MDB_val *b)
1243 return txn->mt_dbxs[dbi].md_cmp(a, b);
1247 mdb_dcmp(MDB_txn *txn, MDB_dbi dbi, const MDB_val *a, const MDB_val *b)
1249 return txn->mt_dbxs[dbi].md_dcmp(a, b);
1252 /** Allocate a single page.
1253 * Re-use old malloc'd pages first, otherwise just malloc.
1256 mdb_page_malloc(MDB_cursor *mc) {
1258 size_t sz = mc->mc_txn->mt_env->me_psize;
1259 if ((ret = mc->mc_txn->mt_env->me_dpages) != NULL) {
1260 VGMEMP_ALLOC(mc->mc_txn->mt_env, ret, sz);
1261 VGMEMP_DEFINED(ret, sizeof(ret->mp_next));
1262 mc->mc_txn->mt_env->me_dpages = ret->mp_next;
1263 } else if ((ret = malloc(sz)) != NULL) {
1264 VGMEMP_ALLOC(mc->mc_txn->mt_env, ret, sz);
1270 mdb_page_free(MDB_env *env, MDB_page *mp)
1272 mp->mp_next = env->me_dpages;
1273 VGMEMP_FREE(env, mp);
1274 env->me_dpages = mp;
1277 /** Allocate pages for writing.
1278 * If there are free pages available from older transactions, they
1279 * will be re-used first. Otherwise a new page will be allocated.
1280 * @param[in] mc cursor A cursor handle identifying the transaction and
1281 * database for which we are allocating.
1282 * @param[in] num the number of pages to allocate.
1283 * @param[out] mp Address of the allocated page(s). Requests for multiple pages
1284 * will always be satisfied by a single contiguous chunk of memory.
1285 * @return 0 on success, non-zero on failure.
1288 mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp)
1290 MDB_txn *txn = mc->mc_txn;
1292 pgno_t pgno = P_INVALID;
1294 txnid_t oldest = 0, last;
1299 /* If our dirty list is already full, we can't do anything */
1300 if (txn->mt_dirty_room == 0)
1301 return MDB_TXN_FULL;
1303 /* The free list won't have any content at all until txn 2 has
1304 * committed. The pages freed by txn 2 will be unreferenced
1305 * after txn 3 commits, and so will be safe to re-use in txn 4.
1307 if (txn->mt_txnid > 3) {
1308 if (!txn->mt_env->me_pghead &&
1309 txn->mt_dbs[FREE_DBI].md_root != P_INVALID) {
1310 /* See if there's anything in the free DB */
1317 mdb_cursor_init(&m2, txn, FREE_DBI, NULL);
1318 if (!txn->mt_env->me_pglast) {
1319 mdb_page_search(&m2, NULL, 0);
1320 leaf = NODEPTR(m2.mc_pg[m2.mc_top], 0);
1321 kptr = (txnid_t *)NODEKEY(leaf);
1326 last = txn->mt_env->me_pglast + 1;
1328 key.mv_data = &last;
1329 key.mv_size = sizeof(last);
1330 rc = mdb_cursor_set(&m2, &key, &data, MDB_SET_RANGE, NULL);
1333 last = *(txnid_t *)key.mv_data;
1339 oldest = txn->mt_txnid - 1;
1340 nr = txn->mt_env->me_txns->mti_numreaders;
1341 r = txn->mt_env->me_txns->mti_readers;
1342 for (i=0; i<nr; i++) {
1343 if (!r[i].mr_pid) continue;
1350 if (oldest > last) {
1351 /* It's usable, grab it.
1355 if (!txn->mt_env->me_pglast) {
1356 mdb_node_read(txn, leaf, &data);
1358 idl = (MDB_ID *) data.mv_data;
1359 /* We might have a zero-length IDL due to freelist growth
1360 * during a prior commit
1363 txn->mt_env->me_pglast = last;
1366 mop = malloc(MDB_IDL_SIZEOF(idl));
1369 txn->mt_env->me_pglast = last;
1370 txn->mt_env->me_pghead = txn->mt_env->me_pgfree = mop;
1371 memcpy(mop, idl, MDB_IDL_SIZEOF(idl));
1376 DPRINTF("IDL read txn %zu root %zu num %zu",
1377 last, txn->mt_dbs[FREE_DBI].md_root, idl[0]);
1378 for (i=0; i<idl[0]; i++) {
1379 DPRINTF("IDL %zu", idl[i+1]);
1386 if (txn->mt_env->me_pghead) {
1387 pgno_t *mop = txn->mt_env->me_pghead;
1390 int retry = 1, readit = 0, n2 = num-1;
1391 unsigned int i, j, k;
1393 /* If current list is too short, must fetch more and coalesce */
1394 if (mop[0] < (unsigned)num)
1397 mdb_cursor_init(&m2, txn, FREE_DBI, NULL);
1399 #ifdef MDB_PARANOID /* Seems like we can ignore this now */
1400 /* If on freelist, don't try to read more. If what we have
1401 * right now isn't enough just use new pages.
1402 * TODO: get all of this working. Many circular dependencies...
1404 if (mc->mc_dbi == FREE_DBI) {
1413 last = txn->mt_env->me_pglast + 1;
1415 /* We haven't hit the readers list yet? */
1421 oldest = txn->mt_txnid - 1;
1422 nr = txn->mt_env->me_txns->mti_numreaders;
1423 r = txn->mt_env->me_txns->mti_readers;
1424 for (i=0; i<nr; i++) {
1425 if (!r[i].mr_pid) continue;
1432 /* There's nothing we can use on the freelist */
1433 if (oldest - last < 1)
1436 key.mv_data = &last;
1437 key.mv_size = sizeof(last);
1438 rc = mdb_cursor_set(&m2,&key,&data,MDB_SET_RANGE,NULL);
1440 if (rc == MDB_NOTFOUND)
1444 last = *(txnid_t*)key.mv_data;
1447 idl = (MDB_ID *) data.mv_data;
1448 mop2 = malloc(MDB_IDL_SIZEOF(idl) + MDB_IDL_SIZEOF(mop));
1451 /* merge in sorted order */
1452 i = idl[0]; j = mop[0]; mop2[0] = k = i+j;
1454 while (i>0 || j>0) {
1455 if (i && idl[i] < mop[j])
1456 mop2[k--] = idl[i--];
1458 mop2[k--] = mop[j--];
1460 txn->mt_env->me_pglast = last;
1461 free(txn->mt_env->me_pgfree);
1462 txn->mt_env->me_pghead = txn->mt_env->me_pgfree = mop2;
1464 /* Keep trying to read until we have enough */
1465 if (mop[0] < (unsigned)num) {
1470 /* current list has enough pages, but are they contiguous? */
1471 for (i=mop[0]; i>=(unsigned)num; i--) {
1472 if (mop[i-n2] == mop[i] + n2) {
1475 /* move any stragglers down */
1476 for (j=i+num; j<=mop[0]; j++)
1483 /* Stop if we succeeded, or no retries */
1484 if (!retry || pgno != P_INVALID)
1490 /* peel pages off tail, so we only have to truncate the list */
1491 pgno = MDB_IDL_LAST(mop);
1494 if (MDB_IDL_IS_ZERO(mop)) {
1495 free(txn->mt_env->me_pgfree);
1496 txn->mt_env->me_pghead = txn->mt_env->me_pgfree = NULL;
1501 if (pgno == P_INVALID) {
1502 /* DB size is maxed out */
1503 if (txn->mt_next_pgno + num >= txn->mt_env->me_maxpg) {
1504 DPUTS("DB size maxed out");
1505 return MDB_MAP_FULL;
1508 if (txn->mt_env->me_flags & MDB_WRITEMAP) {
1509 if (pgno == P_INVALID) {
1510 pgno = txn->mt_next_pgno;
1511 txn->mt_next_pgno += num;
1513 np = (MDB_page *)(txn->mt_env->me_map + txn->mt_env->me_psize * pgno);
1516 if (txn->mt_env->me_dpages && num == 1) {
1517 np = txn->mt_env->me_dpages;
1518 VGMEMP_ALLOC(txn->mt_env, np, txn->mt_env->me_psize);
1519 VGMEMP_DEFINED(np, sizeof(np->mp_next));
1520 txn->mt_env->me_dpages = np->mp_next;
1522 size_t sz = txn->mt_env->me_psize * num;
1523 if ((np = malloc(sz)) == NULL)
1525 VGMEMP_ALLOC(txn->mt_env, np, sz);
1527 if (pgno == P_INVALID) {
1528 np->mp_pgno = txn->mt_next_pgno;
1529 txn->mt_next_pgno += num;
1534 mid.mid = np->mp_pgno;
1536 if (txn->mt_env->me_flags & MDB_WRITEMAP) {
1537 mdb_mid2l_append(txn->mt_u.dirty_list, &mid);
1539 mdb_mid2l_insert(txn->mt_u.dirty_list, &mid);
1541 txn->mt_dirty_room--;
1547 /** Copy a page: avoid copying unused portions of the page.
1548 * @param[in] dst page to copy into
1549 * @param[in] src page to copy from
1552 mdb_page_copy(MDB_page *dst, MDB_page *src, unsigned int psize)
1554 dst->mp_flags = src->mp_flags | P_DIRTY;
1555 dst->mp_pages = src->mp_pages;
1557 if (IS_LEAF2(src)) {
1558 memcpy(dst->mp_ptrs, src->mp_ptrs, psize - PAGEHDRSZ - SIZELEFT(src));
1560 unsigned int i, nkeys = NUMKEYS(src);
1561 for (i=0; i<nkeys; i++)
1562 dst->mp_ptrs[i] = src->mp_ptrs[i];
1563 memcpy((char *)dst+src->mp_upper, (char *)src+src->mp_upper,
1564 psize - src->mp_upper);
1568 /** Touch a page: make it dirty and re-insert into tree with updated pgno.
1569 * @param[in] mc cursor pointing to the page to be touched
1570 * @return 0 on success, non-zero on failure.
1573 mdb_page_touch(MDB_cursor *mc)
1575 MDB_page *mp = mc->mc_pg[mc->mc_top];
1579 if (!F_ISSET(mp->mp_flags, P_DIRTY)) {
1581 if ((rc = mdb_page_alloc(mc, 1, &np)))
1583 DPRINTF("touched db %u page %zu -> %zu", mc->mc_dbi, mp->mp_pgno, np->mp_pgno);
1584 assert(mp->mp_pgno != np->mp_pgno);
1585 mdb_midl_append(&mc->mc_txn->mt_free_pgs, mp->mp_pgno);
1587 /* If page isn't full, just copy the used portion */
1588 mdb_page_copy(np, mp, mc->mc_txn->mt_env->me_psize);
1591 memcpy(np, mp, mc->mc_txn->mt_env->me_psize);
1593 np->mp_flags |= P_DIRTY;
1598 /* Adjust other cursors pointing to mp */
1599 if (mc->mc_flags & C_SUB) {
1600 MDB_cursor *m2, *m3;
1601 MDB_dbi dbi = mc->mc_dbi-1;
1603 for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
1604 if (m2 == mc) continue;
1605 m3 = &m2->mc_xcursor->mx_cursor;
1606 if (m3->mc_snum < mc->mc_snum) continue;
1607 if (m3->mc_pg[mc->mc_top] == mc->mc_pg[mc->mc_top]) {
1608 m3->mc_pg[mc->mc_top] = mp;
1614 for (m2 = mc->mc_txn->mt_cursors[mc->mc_dbi]; m2; m2=m2->mc_next) {
1615 if (m2 == mc || m2->mc_snum < mc->mc_snum) continue;
1616 if (m2->mc_pg[mc->mc_top] == mc->mc_pg[mc->mc_top]) {
1617 m2->mc_pg[mc->mc_top] = mp;
1621 mc->mc_pg[mc->mc_top] = mp;
1622 /** If this page has a parent, update the parent to point to
1626 SETPGNO(NODEPTR(mc->mc_pg[mc->mc_top-1], mc->mc_ki[mc->mc_top-1]), mp->mp_pgno);
1628 mc->mc_db->md_root = mp->mp_pgno;
1629 } else if (mc->mc_txn->mt_parent) {
1632 /* If txn has a parent, make sure the page is in our
1635 if (mc->mc_txn->mt_u.dirty_list[0].mid) {
1636 unsigned x = mdb_mid2l_search(mc->mc_txn->mt_u.dirty_list, mp->mp_pgno);
1637 if (x <= mc->mc_txn->mt_u.dirty_list[0].mid &&
1638 mc->mc_txn->mt_u.dirty_list[x].mid == mp->mp_pgno) {
1639 if (mc->mc_txn->mt_u.dirty_list[x].mptr != mp) {
1640 mp = mc->mc_txn->mt_u.dirty_list[x].mptr;
1641 mc->mc_pg[mc->mc_top] = mp;
1646 assert(mc->mc_txn->mt_u.dirty_list[0].mid < MDB_IDL_UM_MAX);
1648 np = mdb_page_malloc(mc);
1651 memcpy(np, mp, mc->mc_txn->mt_env->me_psize);
1652 mid.mid = np->mp_pgno;
1654 mdb_mid2l_insert(mc->mc_txn->mt_u.dirty_list, &mid);
1662 mdb_env_sync(MDB_env *env, int force)
1665 if (force || !F_ISSET(env->me_flags, MDB_NOSYNC)) {
1666 if (env->me_flags & MDB_WRITEMAP) {
1667 int flags = ((env->me_flags & MDB_MAPASYNC) && !force)
1668 ? MS_ASYNC : MS_SYNC;
1669 if (MDB_MSYNC(env->me_map, env->me_mapsize, flags))
1672 else if (flags == MS_SYNC && MDB_FDATASYNC(env->me_fd))
1676 if (MDB_FDATASYNC(env->me_fd))
1683 /** Make shadow copies of all of parent txn's cursors */
1685 mdb_cursor_shadow(MDB_txn *src, MDB_txn *dst)
1687 MDB_cursor *mc, *m2;
1688 unsigned int i, j, size;
1690 for (i=0;i<src->mt_numdbs; i++) {
1691 if (src->mt_cursors[i]) {
1692 size = sizeof(MDB_cursor);
1693 if (src->mt_cursors[i]->mc_xcursor)
1694 size += sizeof(MDB_xcursor);
1695 for (m2 = src->mt_cursors[i]; m2; m2=m2->mc_next) {
1702 mc->mc_db = &dst->mt_dbs[i];
1703 mc->mc_dbx = m2->mc_dbx;
1704 mc->mc_dbflag = &dst->mt_dbflags[i];
1705 mc->mc_snum = m2->mc_snum;
1706 mc->mc_top = m2->mc_top;
1707 mc->mc_flags = m2->mc_flags | C_SHADOW;
1708 for (j=0; j<mc->mc_snum; j++) {
1709 mc->mc_pg[j] = m2->mc_pg[j];
1710 mc->mc_ki[j] = m2->mc_ki[j];
1712 if (m2->mc_xcursor) {
1713 MDB_xcursor *mx, *mx2;
1714 mx = (MDB_xcursor *)(mc+1);
1715 mc->mc_xcursor = mx;
1716 mx2 = m2->mc_xcursor;
1717 mx->mx_db = mx2->mx_db;
1718 mx->mx_dbx = mx2->mx_dbx;
1719 mx->mx_dbflag = mx2->mx_dbflag;
1720 mx->mx_cursor.mc_txn = dst;
1721 mx->mx_cursor.mc_dbi = mx2->mx_cursor.mc_dbi;
1722 mx->mx_cursor.mc_db = &mx->mx_db;
1723 mx->mx_cursor.mc_dbx = &mx->mx_dbx;
1724 mx->mx_cursor.mc_dbflag = &mx->mx_dbflag;
1725 mx->mx_cursor.mc_snum = mx2->mx_cursor.mc_snum;
1726 mx->mx_cursor.mc_top = mx2->mx_cursor.mc_top;
1727 mx->mx_cursor.mc_flags = mx2->mx_cursor.mc_flags | C_SHADOW;
1728 for (j=0; j<mx2->mx_cursor.mc_snum; j++) {
1729 mx->mx_cursor.mc_pg[j] = mx2->mx_cursor.mc_pg[j];
1730 mx->mx_cursor.mc_ki[j] = mx2->mx_cursor.mc_ki[j];
1733 mc->mc_xcursor = NULL;
1735 mc->mc_next = dst->mt_cursors[i];
1736 dst->mt_cursors[i] = mc;
1743 /** Close this write txn's cursors, after optionally merging its shadow
1744 * cursors back into parent's.
1745 * @param[in] txn the transaction handle.
1746 * @param[in] merge 0 to not merge cursors, C_SHADOW to merge.
1747 * @return 0 on success, non-zero on failure.
1750 mdb_cursors_close(MDB_txn *txn, unsigned merge)
1752 MDB_cursor **cursors = txn->mt_cursors, *mc, *next;
1755 for (i = txn->mt_numdbs; --i >= 0; ) {
1756 for (mc = cursors[i]; mc; mc = next) {
1758 if (mc->mc_flags & merge) {
1759 MDB_cursor *m2 = mc->mc_orig;
1760 m2->mc_snum = mc->mc_snum;
1761 m2->mc_top = mc->mc_top;
1762 for (j = mc->mc_snum; --j >= 0; ) {
1763 m2->mc_pg[j] = mc->mc_pg[j];
1764 m2->mc_ki[j] = mc->mc_ki[j];
1767 if (mc->mc_flags & C_ALLOCD)
1775 mdb_txn_reset0(MDB_txn *txn);
1777 /** Common code for #mdb_txn_begin() and #mdb_txn_renew().
1778 * @param[in] txn the transaction handle to initialize
1779 * @return 0 on success, non-zero on failure.
1782 mdb_txn_renew0(MDB_txn *txn)
1784 MDB_env *env = txn->mt_env;
1787 int rc, new_notls = 0;
1790 txn->mt_numdbs = env->me_numdbs;
1791 txn->mt_dbxs = env->me_dbxs; /* mostly static anyway */
1793 if (txn->mt_flags & MDB_TXN_RDONLY) {
1794 if (!env->me_txns) {
1795 i = mdb_env_pick_meta(env);
1796 txn->mt_txnid = env->me_metas[i]->mm_txnid;
1797 txn->mt_u.reader = NULL;
1799 MDB_reader *r = (env->me_flags & MDB_NOTLS) ? txn->mt_u.reader :
1800 pthread_getspecific(env->me_txkey);
1802 if (r->mr_pid != env->me_pid || r->mr_txnid != (txnid_t)-1)
1803 return MDB_BAD_RSLOT;
1805 pid_t pid = env->me_pid;
1806 pthread_t tid = pthread_self();
1809 for (i=0; i<env->me_txns->mti_numreaders; i++)
1810 if (env->me_txns->mti_readers[i].mr_pid == 0)
1812 if (i == env->me_maxreaders) {
1813 UNLOCK_MUTEX_R(env);
1814 return MDB_READERS_FULL;
1816 env->me_txns->mti_readers[i].mr_pid = pid;
1817 env->me_txns->mti_readers[i].mr_tid = tid;
1818 if (i >= env->me_txns->mti_numreaders)
1819 env->me_txns->mti_numreaders = i+1;
1820 /* Save numreaders for un-mutexed mdb_env_close() */
1821 env->me_numreaders = env->me_txns->mti_numreaders;
1822 UNLOCK_MUTEX_R(env);
1823 r = &env->me_txns->mti_readers[i];
1824 new_notls = (env->me_flags & MDB_NOTLS);
1825 if (!new_notls && (rc=pthread_setspecific(env->me_txkey, r))) {
1830 txn->mt_txnid = r->mr_txnid = env->me_txns->mti_txnid;
1831 txn->mt_u.reader = r;
1833 txn->mt_toggle = txn->mt_txnid & 1;
1834 txn->mt_next_pgno = env->me_metas[txn->mt_toggle]->mm_last_pg+1;
1838 txn->mt_txnid = env->me_txns->mti_txnid;
1839 txn->mt_toggle = txn->mt_txnid & 1;
1840 txn->mt_next_pgno = env->me_metas[txn->mt_toggle]->mm_last_pg+1;
1843 if (txn->mt_txnid == mdb_debug_start)
1846 txn->mt_dirty_room = MDB_IDL_UM_MAX;
1847 txn->mt_u.dirty_list = env->me_dirty_list;
1848 txn->mt_u.dirty_list[0].mid = 0;
1849 txn->mt_free_pgs = env->me_free_pgs;
1850 txn->mt_free_pgs[0] = 0;
1854 /* Copy the DB info and flags */
1855 memcpy(txn->mt_dbs, env->me_metas[txn->mt_toggle]->mm_dbs, 2 * sizeof(MDB_db));
1856 for (i=2; i<txn->mt_numdbs; i++) {
1857 x = env->me_dbflags[i];
1858 txn->mt_dbs[i].md_flags = x & PERSISTENT_FLAGS;
1859 txn->mt_dbflags[i] = (x & MDB_VALID) ? DB_VALID|DB_STALE : 0;
1861 txn->mt_dbflags[0] = txn->mt_dbflags[1] = DB_VALID;
1863 if (env->me_maxpg < txn->mt_next_pgno) {
1864 mdb_txn_reset0(txn);
1866 txn->mt_u.reader->mr_pid = 0;
1867 txn->mt_u.reader = NULL;
1869 return MDB_MAP_RESIZED;
1876 mdb_txn_renew(MDB_txn *txn)
1880 if (!txn || txn->mt_dbxs) /* A reset txn has mt_dbxs==NULL */
1883 if (txn->mt_env->me_flags & MDB_FATAL_ERROR) {
1884 DPUTS("environment had fatal error, must shutdown!");
1888 rc = mdb_txn_renew0(txn);
1889 if (rc == MDB_SUCCESS) {
1890 DPRINTF("renew txn %zu%c %p on mdbenv %p, root page %zu",
1891 txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',
1892 (void *)txn, (void *)txn->mt_env, txn->mt_dbs[MAIN_DBI].md_root);
1898 mdb_txn_begin(MDB_env *env, MDB_txn *parent, unsigned int flags, MDB_txn **ret)
1902 int rc, size, tsize = sizeof(MDB_txn);
1904 if (env->me_flags & MDB_FATAL_ERROR) {
1905 DPUTS("environment had fatal error, must shutdown!");
1908 if ((env->me_flags & MDB_RDONLY) && !(flags & MDB_RDONLY))
1911 /* Nested transactions: Max 1 child, write txns only, no writemap */
1912 if (parent->mt_child ||
1913 (flags & MDB_RDONLY) || (parent->mt_flags & MDB_TXN_RDONLY) ||
1914 (env->me_flags & MDB_WRITEMAP))
1918 tsize = sizeof(MDB_ntxn);
1920 size = tsize + env->me_maxdbs * (sizeof(MDB_db)+1);
1921 if (!(flags & MDB_RDONLY))
1922 size += env->me_maxdbs * sizeof(MDB_cursor *);
1924 if ((txn = calloc(1, size)) == NULL) {
1925 DPRINTF("calloc: %s", strerror(ErrCode()));
1928 txn->mt_dbs = (MDB_db *) ((char *)txn + tsize);
1929 if (flags & MDB_RDONLY) {
1930 txn->mt_flags |= MDB_TXN_RDONLY;
1931 txn->mt_dbflags = (unsigned char *)(txn->mt_dbs + env->me_maxdbs);
1933 txn->mt_cursors = (MDB_cursor **)(txn->mt_dbs + env->me_maxdbs);
1934 txn->mt_dbflags = (unsigned char *)(txn->mt_cursors + env->me_maxdbs);
1940 txn->mt_free_pgs = mdb_midl_alloc();
1941 if (!txn->mt_free_pgs) {
1945 txn->mt_u.dirty_list = malloc(sizeof(MDB_ID2)*MDB_IDL_UM_SIZE);
1946 if (!txn->mt_u.dirty_list) {
1947 free(txn->mt_free_pgs);
1951 txn->mt_txnid = parent->mt_txnid;
1952 txn->mt_toggle = parent->mt_toggle;
1953 txn->mt_dirty_room = parent->mt_dirty_room;
1954 txn->mt_u.dirty_list[0].mid = 0;
1955 txn->mt_free_pgs[0] = 0;
1956 txn->mt_next_pgno = parent->mt_next_pgno;
1957 parent->mt_child = txn;
1958 txn->mt_parent = parent;
1959 txn->mt_numdbs = parent->mt_numdbs;
1960 txn->mt_dbxs = parent->mt_dbxs;
1961 memcpy(txn->mt_dbs, parent->mt_dbs, txn->mt_numdbs * sizeof(MDB_db));
1962 /* Copy parent's mt_dbflags, but clear DB_NEW */
1963 for (i=0; i<txn->mt_numdbs; i++)
1964 txn->mt_dbflags[i] = parent->mt_dbflags[i] & ~DB_NEW;
1966 ntxn = (MDB_ntxn *)txn;
1967 ntxn->mnt_pgstate = env->me_pgstate; /* save parent me_pghead & co */
1968 if (env->me_pghead) {
1969 size = MDB_IDL_SIZEOF(env->me_pghead);
1970 env->me_pghead = malloc(size);
1972 memcpy(env->me_pghead, ntxn->mnt_pgstate.mf_pghead, size);
1976 env->me_pgfree = env->me_pghead;
1978 rc = mdb_cursor_shadow(parent, txn);
1980 mdb_txn_reset0(txn);
1982 rc = mdb_txn_renew0(txn);
1988 DPRINTF("begin txn %zu%c %p on mdbenv %p, root page %zu",
1989 txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',
1990 (void *) txn, (void *) env, txn->mt_dbs[MAIN_DBI].md_root);
1996 /** Export or close DBI handles opened in this txn. */
1998 mdb_dbis_update(MDB_txn *txn, int keep)
2001 MDB_dbi n = txn->mt_numdbs;
2002 MDB_env *env = txn->mt_env;
2003 unsigned char *tdbflags = txn->mt_dbflags;
2005 for (i = n; --i >= 2;) {
2006 if (tdbflags[i] & DB_NEW) {
2008 env->me_dbflags[i] = txn->mt_dbs[i].md_flags | MDB_VALID;
2010 char *ptr = env->me_dbxs[i].md_name.mv_data;
2011 env->me_dbxs[i].md_name.mv_data = NULL;
2012 env->me_dbxs[i].md_name.mv_size = 0;
2013 env->me_dbflags[i] = 0;
2018 if (keep && env->me_numdbs < n)
2022 /** Common code for #mdb_txn_reset() and #mdb_txn_abort().
2023 * May be called twice for readonly txns: First reset it, then abort.
2024 * @param[in] txn the transaction handle to reset
2027 mdb_txn_reset0(MDB_txn *txn)
2029 MDB_env *env = txn->mt_env;
2032 /* Close any DBI handles opened in this txn */
2033 mdb_dbis_update(txn, 0);
2035 if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
2036 if (txn->mt_u.reader) {
2037 txn->mt_u.reader->mr_txnid = (txnid_t)-1;
2038 if (!(env->me_flags & MDB_NOTLS))
2039 txn->mt_u.reader = NULL; /* txn does not own reader */
2041 txn->mt_numdbs = 0; /* close nothing if called again */
2042 txn->mt_dbxs = NULL; /* mark txn as reset */
2046 mdb_cursors_close(txn, 0);
2048 if (!(env->me_flags & MDB_WRITEMAP)) {
2049 /* return all dirty pages to dpage list */
2050 for (i=1; i<=txn->mt_u.dirty_list[0].mid; i++) {
2051 dp = txn->mt_u.dirty_list[i].mptr;
2052 if (!IS_OVERFLOW(dp) || dp->mp_pages == 1) {
2053 mdb_page_free(txn->mt_env, dp);
2055 /* large pages just get freed directly */
2056 VGMEMP_FREE(txn->mt_env, dp);
2062 free(env->me_pgfree);
2064 if (txn->mt_parent) {
2065 txn->mt_parent->mt_child = NULL;
2066 env->me_pgstate = ((MDB_ntxn *)txn)->mnt_pgstate;
2067 mdb_midl_free(txn->mt_free_pgs);
2068 free(txn->mt_u.dirty_list);
2071 if (mdb_midl_shrink(&txn->mt_free_pgs))
2072 env->me_free_pgs = txn->mt_free_pgs;
2075 txn->mt_env->me_pghead = txn->mt_env->me_pgfree = NULL;
2076 txn->mt_env->me_pglast = 0;
2079 /* The writer mutex was locked in mdb_txn_begin. */
2080 UNLOCK_MUTEX_W(env);
2085 mdb_txn_reset(MDB_txn *txn)
2090 DPRINTF("reset txn %zu%c %p on mdbenv %p, root page %zu",
2091 txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',
2092 (void *) txn, (void *)txn->mt_env, txn->mt_dbs[MAIN_DBI].md_root);
2094 /* This call is only valid for read-only txns */
2095 if (!(txn->mt_flags & MDB_TXN_RDONLY))
2098 mdb_txn_reset0(txn);
2102 mdb_txn_abort(MDB_txn *txn)
2107 DPRINTF("abort txn %zu%c %p on mdbenv %p, root page %zu",
2108 txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',
2109 (void *)txn, (void *)txn->mt_env, txn->mt_dbs[MAIN_DBI].md_root);
2112 mdb_txn_abort(txn->mt_child);
2114 mdb_txn_reset0(txn);
2115 /* Free reader slot tied to this txn (if MDB_NOTLS && writable FS) */
2116 if ((txn->mt_flags & MDB_TXN_RDONLY) && txn->mt_u.reader)
2117 txn->mt_u.reader->mr_pid = 0;
2123 mdb_txn_commit(MDB_txn *txn)
2131 pgno_t next, freecnt;
2132 txnid_t oldpg_txnid, id;
2135 assert(txn != NULL);
2136 assert(txn->mt_env != NULL);
2138 if (txn->mt_child) {
2139 mdb_txn_commit(txn->mt_child);
2140 txn->mt_child = NULL;
2145 if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
2146 mdb_dbis_update(txn, 1);
2147 txn->mt_numdbs = 2; /* so txn_abort() doesn't close any new handles */
2152 if (F_ISSET(txn->mt_flags, MDB_TXN_ERROR)) {
2153 DPUTS("error flag is set, can't commit");
2155 txn->mt_parent->mt_flags |= MDB_TXN_ERROR;
2160 if (txn->mt_parent) {
2161 MDB_txn *parent = txn->mt_parent;
2165 /* Append our free list to parent's */
2166 if (mdb_midl_append_list(&parent->mt_free_pgs, txn->mt_free_pgs)) {
2170 mdb_midl_free(txn->mt_free_pgs);
2172 parent->mt_next_pgno = txn->mt_next_pgno;
2173 parent->mt_flags = txn->mt_flags;
2175 /* Merge our cursors into parent's and close them */
2176 mdb_cursors_close(txn, C_SHADOW);
2178 /* Update parent's DB table. */
2179 memcpy(parent->mt_dbs, txn->mt_dbs, txn->mt_numdbs * sizeof(MDB_db));
2180 txn->mt_parent->mt_numdbs = txn->mt_numdbs;
2181 txn->mt_parent->mt_dbflags[0] = txn->mt_dbflags[0];
2182 txn->mt_parent->mt_dbflags[1] = txn->mt_dbflags[1];
2183 for (i=2; i<txn->mt_numdbs; i++) {
2184 /* preserve parent's DB_NEW status */
2185 x = txn->mt_parent->mt_dbflags[i] & DB_NEW;
2186 txn->mt_parent->mt_dbflags[i] = txn->mt_dbflags[i] | x;
2189 dst = txn->mt_parent->mt_u.dirty_list;
2190 src = txn->mt_u.dirty_list;
2191 /* Find len = length of merging our dirty list with parent's */
2193 dst[0].mid = 0; /* simplify loops */
2194 if (parent->mt_parent) {
2195 len = x + src[0].mid;
2196 y = mdb_mid2l_search(src, dst[x].mid + 1) - 1;
2197 for (i = x; y && i; y--) {
2198 pgno_t yp = src[y].mid;
2199 while (yp < dst[i].mid)
2201 if (yp == dst[i].mid) {
2206 } else { /* Simplify the above for single-ancestor case */
2207 len = MDB_IDL_UM_MAX - txn->mt_dirty_room;
2209 /* Merge our dirty list with parent's */
2211 for (i = len; y; dst[i--] = src[y--]) {
2212 pgno_t yp = src[y].mid;
2213 while (yp < dst[x].mid)
2214 dst[i--] = dst[x--];
2215 if (yp == dst[x].mid)
2216 free(dst[x--].mptr);
2220 free(txn->mt_u.dirty_list);
2221 parent->mt_dirty_room = txn->mt_dirty_room;
2223 txn->mt_parent->mt_child = NULL;
2224 free(((MDB_ntxn *)txn)->mnt_pgstate.mf_pgfree);
2229 if (txn != env->me_txn) {
2230 DPUTS("attempt to commit unknown transaction");
2235 mdb_cursors_close(txn, 0);
2237 if (!txn->mt_u.dirty_list[0].mid && !(txn->mt_flags & MDB_TXN_DIRTY))
2240 DPRINTF("committing txn %zu %p on mdbenv %p, root page %zu",
2241 txn->mt_txnid, (void *)txn, (void *)env, txn->mt_dbs[MAIN_DBI].md_root);
2243 /* Update DB root pointers */
2244 if (txn->mt_numdbs > 2) {
2247 data.mv_size = sizeof(MDB_db);
2249 mdb_cursor_init(&mc, txn, MAIN_DBI, NULL);
2250 for (i = 2; i < txn->mt_numdbs; i++) {
2251 if (txn->mt_dbflags[i] & DB_DIRTY) {
2252 data.mv_data = &txn->mt_dbs[i];
2253 rc = mdb_cursor_put(&mc, &txn->mt_dbxs[i].md_name, &data, 0);
2260 /* Save the freelist as of this transaction to the freeDB. This
2261 * can change the freelist, so keep trying until it stabilizes.
2263 * env->me_pglast and the length of txn->mt_free_pgs cannot decrease,
2264 * except the code below can decrease env->me_pglast to split pghead.
2265 * Page numbers cannot disappear from txn->mt_free_pgs. New pages
2266 * can only appear in env->me_pghead when env->me_pglast increases.
2267 * Until then, the me_pghead pointer won't move but can become NULL.
2270 mdb_cursor_init(&mc, txn, FREE_DBI, NULL);
2271 oldpg_txnid = id = 0;
2274 /* should only be one record now */
2275 if (env->me_pghead || env->me_pglast) {
2276 /* make sure first page of freeDB is touched and on freelist */
2277 rc = mdb_page_search(&mc, NULL, MDB_PS_MODIFY);
2278 if (rc && rc != MDB_NOTFOUND) {
2285 /* Delete IDLs we used from the free list */
2286 if (env->me_pglast) {
2291 rc = mdb_cursor_first(&mc, &key, NULL);
2294 oldpg_txnid = *(txnid_t *)key.mv_data;
2296 assert(oldpg_txnid <= env->me_pglast);
2298 rc = mdb_cursor_del(&mc, 0);
2301 } while (oldpg_txnid < env->me_pglast);
2304 /* Save IDL of pages freed by this txn, to freeDB */
2306 if (freecnt != txn->mt_free_pgs[0]) {
2309 /* make sure last page of freeDB is touched and on freelist */
2310 key.mv_size = MDB_MAXKEYSIZE+1;
2312 rc = mdb_page_search(&mc, &key, MDB_PS_MODIFY);
2313 if (rc && rc != MDB_NOTFOUND)
2319 MDB_IDL idl = txn->mt_free_pgs;
2320 mdb_midl_sort(txn->mt_free_pgs);
2321 DPRINTF("IDL write txn %zu root %zu num %zu",
2322 txn->mt_txnid, txn->mt_dbs[FREE_DBI].md_root, idl[0]);
2323 for (i=1; i<=idl[0]; i++) {
2324 DPRINTF("IDL %zu", idl[i]);
2328 /* write to last page of freeDB */
2329 key.mv_size = sizeof(pgno_t);
2330 key.mv_data = &txn->mt_txnid;
2331 /* The free list can still grow during this call,
2332 * despite the pre-emptive touches above. So retry
2333 * until the reserved space remains big enough.
2336 assert(freecnt < txn->mt_free_pgs[0]);
2337 freecnt = txn->mt_free_pgs[0];
2338 data.mv_size = MDB_IDL_SIZEOF(txn->mt_free_pgs);
2339 rc = mdb_cursor_put(&mc, &key, &data, MDB_RESERVE);
2342 } while (freecnt != txn->mt_free_pgs[0]);
2343 mdb_midl_sort(txn->mt_free_pgs);
2344 memcpy(data.mv_data, txn->mt_free_pgs, data.mv_size);
2345 if (oldpg_txnid < env->me_pglast || (!env->me_pghead && id))
2346 goto free_pgfirst; /* used up freeDB[oldpg_txnid] */
2349 /* Put back page numbers we took from freeDB but did not use */
2350 if (env->me_pghead) {
2355 mop = env->me_pghead;
2356 id = env->me_pglast;
2357 key.mv_size = sizeof(id);
2359 /* These steps may grow the freelist again
2360 * due to freed overflow pages...
2365 if (orig > env->me_maxfree_1pg && id > 4)
2366 orig = env->me_maxfree_1pg; /* Do not use more than 1 page */
2367 data.mv_size = (orig + 1) * sizeof(pgno_t);
2368 rc = mdb_cursor_put(&mc, &key, &data, MDB_RESERVE);
2371 assert(!env->me_pghead || env->me_pglast);
2372 /* mop could have been used again here */
2373 if (id != env->me_pglast || env->me_pghead == NULL)
2374 goto again; /* was completely used up */
2375 assert(mop == env->me_pghead);
2376 } while (mop[0] < orig && --i);
2377 memcpy(data.mv_data, mop, data.mv_size);
2380 *(pgno_t *)data.mv_data = orig;
2381 mop[orig] = mop[0] - orig;
2382 env->me_pghead = mop += orig;
2383 /* Save more oldpages at the previous txnid. */
2384 assert(env->me_pglast == id && id == oldpg_txnid);
2385 env->me_pglast = --oldpg_txnid;
2389 /* Check for growth of freelist again */
2390 if (freecnt != txn->mt_free_pgs[0])
2393 free(env->me_pgfree);
2394 env->me_pghead = env->me_pgfree = NULL;
2396 if (!MDB_IDL_IS_ZERO(txn->mt_free_pgs)) {
2397 if (mdb_midl_shrink(&txn->mt_free_pgs))
2398 env->me_free_pgs = txn->mt_free_pgs;
2405 if (env->me_flags & MDB_WRITEMAP) {
2406 for (i=1; i<=txn->mt_u.dirty_list[0].mid; i++) {
2407 dp = txn->mt_u.dirty_list[i].mptr;
2408 /* clear dirty flag */
2409 dp->mp_flags &= ~P_DIRTY;
2410 txn->mt_u.dirty_list[i].mid = 0;
2412 txn->mt_u.dirty_list[0].mid = 0;
2416 /* Commit up to MDB_COMMIT_PAGES dirty pages to disk until done.
2422 /* Windows actually supports scatter/gather I/O, but only on
2423 * unbuffered file handles. Since we're relying on the OS page
2424 * cache for all our data, that's self-defeating. So we just
2425 * write pages one at a time. We use the ov structure to set
2426 * the write offset, to at least save the overhead of a Seek
2430 memset(&ov, 0, sizeof(ov));
2431 for (; i<=txn->mt_u.dirty_list[0].mid; i++) {
2433 dp = txn->mt_u.dirty_list[i].mptr;
2434 DPRINTF("committing page %zu", dp->mp_pgno);
2435 size = dp->mp_pgno * env->me_psize;
2436 ov.Offset = size & 0xffffffff;
2437 ov.OffsetHigh = size >> 16;
2438 ov.OffsetHigh >>= 16;
2439 /* clear dirty flag */
2440 dp->mp_flags &= ~P_DIRTY;
2441 wsize = env->me_psize;
2442 if (IS_OVERFLOW(dp)) wsize *= dp->mp_pages;
2443 rc = WriteFile(env->me_fd, dp, wsize, NULL, &ov);
2446 DPRINTF("WriteFile: %d", n);
2453 struct iovec iov[MDB_COMMIT_PAGES];
2457 for (; i<=txn->mt_u.dirty_list[0].mid; i++) {
2458 dp = txn->mt_u.dirty_list[i].mptr;
2459 if (dp->mp_pgno != next) {
2461 rc = writev(env->me_fd, iov, n);
2465 DPUTS("short write, filesystem full?");
2467 DPRINTF("writev: %s", strerror(n));
2474 lseek(env->me_fd, dp->mp_pgno * env->me_psize, SEEK_SET);
2477 DPRINTF("committing page %zu", dp->mp_pgno);
2478 iov[n].iov_len = env->me_psize;
2479 if (IS_OVERFLOW(dp)) iov[n].iov_len *= dp->mp_pages;
2480 iov[n].iov_base = (char *)dp;
2481 size += iov[n].iov_len;
2482 next = dp->mp_pgno + (IS_OVERFLOW(dp) ? dp->mp_pages : 1);
2483 /* clear dirty flag */
2484 dp->mp_flags &= ~P_DIRTY;
2485 if (++n >= MDB_COMMIT_PAGES) {
2495 rc = writev(env->me_fd, iov, n);
2499 DPUTS("short write, filesystem full?");
2501 DPRINTF("writev: %s", strerror(n));
2508 /* Drop the dirty pages.
2510 for (i=1; i<=txn->mt_u.dirty_list[0].mid; i++) {
2511 dp = txn->mt_u.dirty_list[i].mptr;
2512 if (!IS_OVERFLOW(dp) || dp->mp_pages == 1) {
2513 mdb_page_free(txn->mt_env, dp);
2515 VGMEMP_FREE(txn->mt_env, dp);
2518 txn->mt_u.dirty_list[i].mid = 0;
2520 txn->mt_u.dirty_list[0].mid = 0;
2523 if ((n = mdb_env_sync(env, 0)) != 0 ||
2524 (n = mdb_env_write_meta(txn)) != MDB_SUCCESS) {
2532 mdb_dbis_update(txn, 1);
2534 UNLOCK_MUTEX_W(env);
2540 /** Read the environment parameters of a DB environment before
2541 * mapping it into memory.
2542 * @param[in] env the environment handle
2543 * @param[out] meta address of where to store the meta information
2544 * @return 0 on success, non-zero on failure.
2547 mdb_env_read_header(MDB_env *env, MDB_meta *meta)
2554 /* We don't know the page size yet, so use a minimum value.
2555 * Read both meta pages so we can use the latest one.
2558 for (i=0; i<2; i++) {
2560 if (!ReadFile(env->me_fd, &pbuf, MDB_PAGESIZE, (DWORD *)&rc, NULL) || rc == 0)
2562 if ((rc = read(env->me_fd, &pbuf, MDB_PAGESIZE)) == 0)
2567 else if (rc != MDB_PAGESIZE) {
2571 DPRINTF("read: %s", strerror(err));
2575 p = (MDB_page *)&pbuf;
2577 if (!F_ISSET(p->mp_flags, P_META)) {
2578 DPRINTF("page %zu not a meta page", p->mp_pgno);
2583 if (m->mm_magic != MDB_MAGIC) {
2584 DPUTS("meta has invalid magic");
2588 if (m->mm_version != MDB_VERSION) {
2589 DPRINTF("database is version %u, expected version %u",
2590 m->mm_version, MDB_VERSION);
2591 return MDB_VERSION_MISMATCH;
2595 if (m->mm_txnid > meta->mm_txnid)
2596 memcpy(meta, m, sizeof(*m));
2598 memcpy(meta, m, sizeof(*m));
2600 if (SetFilePointer(env->me_fd, meta->mm_psize, NULL, FILE_BEGIN) != meta->mm_psize)
2602 if (lseek(env->me_fd, meta->mm_psize, SEEK_SET) != meta->mm_psize)
2610 /** Write the environment parameters of a freshly created DB environment.
2611 * @param[in] env the environment handle
2612 * @param[out] meta address of where to store the meta information
2613 * @return 0 on success, non-zero on failure.
2616 mdb_env_init_meta(MDB_env *env, MDB_meta *meta)
2623 DPUTS("writing new meta page");
2625 GET_PAGESIZE(psize);
2627 meta->mm_magic = MDB_MAGIC;
2628 meta->mm_version = MDB_VERSION;
2629 meta->mm_mapsize = env->me_mapsize;
2630 meta->mm_psize = psize;
2631 meta->mm_last_pg = 1;
2632 meta->mm_flags = env->me_flags & 0xffff;
2633 meta->mm_flags |= MDB_INTEGERKEY;
2634 meta->mm_dbs[0].md_root = P_INVALID;
2635 meta->mm_dbs[1].md_root = P_INVALID;
2637 p = calloc(2, psize);
2639 p->mp_flags = P_META;
2642 memcpy(m, meta, sizeof(*meta));
2644 q = (MDB_page *)((char *)p + psize);
2647 q->mp_flags = P_META;
2650 memcpy(m, meta, sizeof(*meta));
2655 SetFilePointer(env->me_fd, 0, NULL, FILE_BEGIN);
2656 rc = WriteFile(env->me_fd, p, psize * 2, &len, NULL);
2657 rc = (len == psize * 2) ? MDB_SUCCESS : ErrCode();
2660 lseek(env->me_fd, 0, SEEK_SET);
2661 rc = write(env->me_fd, p, psize * 2);
2662 rc = (rc == (int)psize * 2) ? MDB_SUCCESS : ErrCode();
2668 /** Update the environment info to commit a transaction.
2669 * @param[in] txn the transaction that's being committed
2670 * @return 0 on success, non-zero on failure.
2673 mdb_env_write_meta(MDB_txn *txn)
2676 MDB_meta meta, metab, *mp;
2678 int rc, len, toggle;
2685 assert(txn != NULL);
2686 assert(txn->mt_env != NULL);
2688 toggle = !txn->mt_toggle;
2689 DPRINTF("writing meta page %d for root page %zu",
2690 toggle, txn->mt_dbs[MAIN_DBI].md_root);
2693 mp = env->me_metas[toggle];
2695 if (env->me_flags & MDB_WRITEMAP) {
2696 /* Persist any increases of mapsize config */
2697 if (env->me_mapsize > mp->mm_mapsize)
2698 mp->mm_mapsize = env->me_mapsize;
2699 mp->mm_dbs[0] = txn->mt_dbs[0];
2700 mp->mm_dbs[1] = txn->mt_dbs[1];
2701 mp->mm_last_pg = txn->mt_next_pgno - 1;
2702 mp->mm_txnid = txn->mt_txnid;
2703 if (!(env->me_flags & (MDB_NOMETASYNC|MDB_NOSYNC))) {
2704 rc = (env->me_flags & MDB_MAPASYNC) ? MS_ASYNC : MS_SYNC;
2707 ptr += env->me_psize;
2708 if (MDB_MSYNC(ptr, env->me_psize, rc)) {
2715 metab.mm_txnid = env->me_metas[toggle]->mm_txnid;
2716 metab.mm_last_pg = env->me_metas[toggle]->mm_last_pg;
2718 ptr = (char *)&meta;
2719 if (env->me_mapsize > mp->mm_mapsize) {
2720 /* Persist any increases of mapsize config */
2721 meta.mm_mapsize = env->me_mapsize;
2722 off = offsetof(MDB_meta, mm_mapsize);
2724 off = offsetof(MDB_meta, mm_dbs[0].md_depth);
2726 len = sizeof(MDB_meta) - off;
2729 meta.mm_dbs[0] = txn->mt_dbs[0];
2730 meta.mm_dbs[1] = txn->mt_dbs[1];
2731 meta.mm_last_pg = txn->mt_next_pgno - 1;
2732 meta.mm_txnid = txn->mt_txnid;
2735 off += env->me_psize;
2738 /* Write to the SYNC fd */
2739 mfd = env->me_flags & (MDB_NOSYNC|MDB_NOMETASYNC) ?
2740 env->me_fd : env->me_mfd;
2743 memset(&ov, 0, sizeof(ov));
2745 WriteFile(mfd, ptr, len, (DWORD *)&rc, &ov);
2748 rc = pwrite(mfd, ptr, len, off);
2753 DPUTS("write failed, disk error?");
2754 /* On a failure, the pagecache still contains the new data.
2755 * Write some old data back, to prevent it from being used.
2756 * Use the non-SYNC fd; we know it will fail anyway.
2758 meta.mm_last_pg = metab.mm_last_pg;
2759 meta.mm_txnid = metab.mm_txnid;
2761 WriteFile(env->me_fd, ptr, len, NULL, &ov);
2763 r2 = pwrite(env->me_fd, ptr, len, off);
2766 env->me_flags |= MDB_FATAL_ERROR;
2770 /* Memory ordering issues are irrelevant; since the entire writer
2771 * is wrapped by wmutex, all of these changes will become visible
2772 * after the wmutex is unlocked. Since the DB is multi-version,
2773 * readers will get consistent data regardless of how fresh or
2774 * how stale their view of these values is.
2776 txn->mt_env->me_txns->mti_txnid = txn->mt_txnid;
2781 /** Check both meta pages to see which one is newer.
2782 * @param[in] env the environment handle
2783 * @return meta toggle (0 or 1).
2786 mdb_env_pick_meta(const MDB_env *env)
2788 return (env->me_metas[0]->mm_txnid < env->me_metas[1]->mm_txnid);
2792 mdb_env_create(MDB_env **env)
2796 e = calloc(1, sizeof(MDB_env));
2800 e->me_maxreaders = DEFAULT_READERS;
2801 e->me_maxdbs = e->me_numdbs = 2;
2802 e->me_fd = INVALID_HANDLE_VALUE;
2803 e->me_lfd = INVALID_HANDLE_VALUE;
2804 e->me_mfd = INVALID_HANDLE_VALUE;
2805 #ifdef MDB_USE_POSIX_SEM
2806 e->me_rmutex = SEM_FAILED;
2807 e->me_wmutex = SEM_FAILED;
2809 e->me_pid = getpid();
2810 VGMEMP_CREATE(e,0,0);
2816 mdb_env_set_mapsize(MDB_env *env, size_t size)
2820 env->me_mapsize = size;
2822 env->me_maxpg = env->me_mapsize / env->me_psize;
2827 mdb_env_set_maxdbs(MDB_env *env, MDB_dbi dbs)
2831 env->me_maxdbs = dbs + 2; /* Named databases + main and free DB */
2836 mdb_env_set_maxreaders(MDB_env *env, unsigned int readers)
2838 if (env->me_map || readers < 1)
2840 env->me_maxreaders = readers;
2845 mdb_env_get_maxreaders(MDB_env *env, unsigned int *readers)
2847 if (!env || !readers)
2849 *readers = env->me_maxreaders;
2853 /** Further setup required for opening an MDB environment
2856 mdb_env_open2(MDB_env *env)
2858 unsigned int flags = env->me_flags;
2859 int i, newenv = 0, prot;
2863 memset(&meta, 0, sizeof(meta));
2865 if ((i = mdb_env_read_header(env, &meta)) != 0) {
2868 DPUTS("new mdbenv");
2872 /* Was a mapsize configured? */
2873 if (!env->me_mapsize) {
2874 /* If this is a new environment, take the default,
2875 * else use the size recorded in the existing env.
2877 env->me_mapsize = newenv ? DEFAULT_MAPSIZE : meta.mm_mapsize;
2878 } else if (env->me_mapsize < meta.mm_mapsize) {
2879 /* If the configured size is smaller, make sure it's
2880 * still big enough. Silently round up to minimum if not.
2882 size_t minsize = (meta.mm_last_pg + 1) * meta.mm_psize;
2883 if (env->me_mapsize < minsize)
2884 env->me_mapsize = minsize;
2890 LONG sizelo, sizehi;
2891 sizelo = env->me_mapsize & 0xffffffff;
2892 sizehi = env->me_mapsize >> 16; /* pointless on WIN32, only needed on W64 */
2894 /* Windows won't create mappings for zero length files.
2895 * Just allocate the maxsize right now.
2898 SetFilePointer(env->me_fd, sizelo, sizehi ? &sizehi : NULL, 0);
2899 if (!SetEndOfFile(env->me_fd))
2901 SetFilePointer(env->me_fd, 0, NULL, 0);
2903 mh = CreateFileMapping(env->me_fd, NULL, flags & MDB_WRITEMAP ?
2904 PAGE_READWRITE : PAGE_READONLY,
2905 sizehi, sizelo, NULL);
2908 env->me_map = MapViewOfFileEx(mh, flags & MDB_WRITEMAP ?
2909 FILE_MAP_WRITE : FILE_MAP_READ,
2910 0, 0, env->me_mapsize, meta.mm_address);
2918 if (flags & MDB_WRITEMAP) {
2920 if (ftruncate(env->me_fd, env->me_mapsize) < 0)
2923 env->me_map = mmap(meta.mm_address, env->me_mapsize, prot, i,
2925 if (env->me_map == MAP_FAILED) {
2929 /* Turn off readahead. It's harmful when the DB is larger than RAM. */
2931 madvise(env->me_map, env->me_mapsize, MADV_RANDOM);
2933 #ifdef POSIX_MADV_RANDOM
2934 posix_madvise(env->me_map, env->me_mapsize, POSIX_MADV_RANDOM);
2935 #endif /* POSIX_MADV_RANDOM */
2936 #endif /* MADV_RANDOM */
2940 if (flags & MDB_FIXEDMAP)
2941 meta.mm_address = env->me_map;
2942 i = mdb_env_init_meta(env, &meta);
2943 if (i != MDB_SUCCESS) {
2946 } else if (meta.mm_address && env->me_map != meta.mm_address) {
2947 /* Can happen because the address argument to mmap() is just a
2948 * hint. mmap() can pick another, e.g. if the range is in use.
2949 * The MAP_FIXED flag would prevent that, but then mmap could
2950 * instead unmap existing pages to make room for the new map.
2952 return EBUSY; /* TODO: Make a new MDB_* error code? */
2954 env->me_psize = meta.mm_psize;
2955 env->me_maxfree_1pg = (env->me_psize - PAGEHDRSZ) / sizeof(pgno_t) - 1;
2956 env->me_nodemax = (env->me_psize - PAGEHDRSZ) / MDB_MINKEYS;
2958 env->me_maxpg = env->me_mapsize / env->me_psize;
2960 p = (MDB_page *)env->me_map;
2961 env->me_metas[0] = METADATA(p);
2962 env->me_metas[1] = (MDB_meta *)((char *)env->me_metas[0] + meta.mm_psize);
2966 int toggle = mdb_env_pick_meta(env);
2967 MDB_db *db = &env->me_metas[toggle]->mm_dbs[MAIN_DBI];
2969 DPRINTF("opened database version %u, pagesize %u",
2970 env->me_metas[0]->mm_version, env->me_psize);
2971 DPRINTF("using meta page %d", toggle);
2972 DPRINTF("depth: %u", db->md_depth);
2973 DPRINTF("entries: %zu", db->md_entries);
2974 DPRINTF("branch pages: %zu", db->md_branch_pages);
2975 DPRINTF("leaf pages: %zu", db->md_leaf_pages);
2976 DPRINTF("overflow pages: %zu", db->md_overflow_pages);
2977 DPRINTF("root: %zu", db->md_root);
2985 /** Release a reader thread's slot in the reader lock table.
2986 * This function is called automatically when a thread exits.
2987 * @param[in] ptr This points to the slot in the reader lock table.
2990 mdb_env_reader_dest(void *ptr)
2992 MDB_reader *reader = ptr;
2998 /** Junk for arranging thread-specific callbacks on Windows. This is
2999 * necessarily platform and compiler-specific. Windows supports up
3000 * to 1088 keys. Let's assume nobody opens more than 64 environments
3001 * in a single process, for now. They can override this if needed.
3003 #ifndef MAX_TLS_KEYS
3004 #define MAX_TLS_KEYS 64
3006 static pthread_key_t mdb_tls_keys[MAX_TLS_KEYS];
3007 static int mdb_tls_nkeys;
3009 static void NTAPI mdb_tls_callback(PVOID module, DWORD reason, PVOID ptr)
3013 case DLL_PROCESS_ATTACH: break;
3014 case DLL_THREAD_ATTACH: break;
3015 case DLL_THREAD_DETACH:
3016 for (i=0; i<mdb_tls_nkeys; i++) {
3017 MDB_reader *r = pthread_getspecific(mdb_tls_keys[i]);
3018 mdb_env_reader_dest(r);
3021 case DLL_PROCESS_DETACH: break;
3026 const PIMAGE_TLS_CALLBACK mdb_tls_cbp __attribute__((section (".CRT$XLB"))) = mdb_tls_callback;
3028 PIMAGE_TLS_CALLBACK mdb_tls_cbp __attribute__((section (".CRT$XLB"))) = mdb_tls_callback;
3032 /* Force some symbol references.
3033 * _tls_used forces the linker to create the TLS directory if not already done
3034 * mdb_tls_cbp prevents whole-program-optimizer from dropping the symbol.
3036 #pragma comment(linker, "/INCLUDE:_tls_used")
3037 #pragma comment(linker, "/INCLUDE:mdb_tls_cbp")
3038 #pragma const_seg(".CRT$XLB")
3039 extern const PIMAGE_TLS_CALLBACK mdb_tls_callback;
3040 const PIMAGE_TLS_CALLBACK mdb_tls_cbp = mdb_tls_callback;
3043 #pragma comment(linker, "/INCLUDE:__tls_used")
3044 #pragma comment(linker, "/INCLUDE:_mdb_tls_cbp")
3045 #pragma data_seg(".CRT$XLB")
3046 PIMAGE_TLS_CALLBACK mdb_tls_cbp = mdb_tls_callback;
3048 #endif /* WIN 32/64 */
3049 #endif /* !__GNUC__ */
3052 /** Downgrade the exclusive lock on the region back to shared */
3054 mdb_env_share_locks(MDB_env *env, int *excl)
3056 int rc = 0, toggle = mdb_env_pick_meta(env);
3058 env->me_txns->mti_txnid = env->me_metas[toggle]->mm_txnid;
3063 /* First acquire a shared lock. The Unlock will
3064 * then release the existing exclusive lock.
3066 memset(&ov, 0, sizeof(ov));
3067 if (!LockFileEx(env->me_lfd, 0, 0, 1, 0, &ov)) {
3070 UnlockFile(env->me_lfd, 0, 0, 1, 0);
3076 struct flock lock_info;
3077 /* The shared lock replaces the existing lock */
3078 memset((void *)&lock_info, 0, sizeof(lock_info));
3079 lock_info.l_type = F_RDLCK;
3080 lock_info.l_whence = SEEK_SET;
3081 lock_info.l_start = 0;
3082 lock_info.l_len = 1;
3083 while ((rc = fcntl(env->me_lfd, F_SETLK, &lock_info)) &&
3084 (rc = ErrCode()) == EINTR) ;
3085 *excl = rc ? -1 : 0; /* error may mean we lost the lock */
3092 /** Try to get exlusive lock, otherwise shared.
3093 * Maintain *excl = -1: no/unknown lock, 0: shared, 1: exclusive.
3096 mdb_env_excl_lock(MDB_env *env, int *excl)
3100 if (LockFile(env->me_lfd, 0, 0, 1, 0)) {
3104 memset(&ov, 0, sizeof(ov));
3105 if (LockFileEx(env->me_lfd, 0, 0, 1, 0, &ov)) {
3112 struct flock lock_info;
3113 memset((void *)&lock_info, 0, sizeof(lock_info));
3114 lock_info.l_type = F_WRLCK;
3115 lock_info.l_whence = SEEK_SET;
3116 lock_info.l_start = 0;
3117 lock_info.l_len = 1;
3118 while ((rc = fcntl(env->me_lfd, F_SETLK, &lock_info)) &&
3119 (rc = ErrCode()) == EINTR) ;
3123 # ifdef MDB_USE_POSIX_SEM
3124 if (*excl < 0) /* always true when !MDB_USE_POSIX_SEM */
3127 lock_info.l_type = F_RDLCK;
3128 while ((rc = fcntl(env->me_lfd, F_SETLKW, &lock_info)) &&
3129 (rc = ErrCode()) == EINTR) ;
3137 #if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
3139 * hash_64 - 64 bit Fowler/Noll/Vo-0 FNV-1a hash code
3141 * @(#) $Revision: 5.1 $
3142 * @(#) $Id: hash_64a.c,v 5.1 2009/06/30 09:01:38 chongo Exp $
3143 * @(#) $Source: /usr/local/src/cmd/fnv/RCS/hash_64a.c,v $
3145 * http://www.isthe.com/chongo/tech/comp/fnv/index.html
3149 * Please do not copyright this code. This code is in the public domain.
3151 * LANDON CURT NOLL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
3152 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO
3153 * EVENT SHALL LANDON CURT NOLL BE LIABLE FOR ANY SPECIAL, INDIRECT OR
3154 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
3155 * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
3156 * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
3157 * PERFORMANCE OF THIS SOFTWARE.
3160 * chongo <Landon Curt Noll> /\oo/\
3161 * http://www.isthe.com/chongo/
3163 * Share and Enjoy! :-)
3166 typedef unsigned long long mdb_hash_t;
3167 #define MDB_HASH_INIT ((mdb_hash_t)0xcbf29ce484222325ULL)
3169 /** perform a 64 bit Fowler/Noll/Vo FNV-1a hash on a buffer
3170 * @param[in] str string to hash
3171 * @param[in] hval initial value for hash
3172 * @return 64 bit hash
3174 * NOTE: To use the recommended 64 bit FNV-1a hash, use MDB_HASH_INIT as the
3175 * hval arg on the first call.
3178 mdb_hash_val(MDB_val *val, mdb_hash_t hval)
3180 unsigned char *s = (unsigned char *)val->mv_data; /* unsigned string */
3181 unsigned char *end = s + val->mv_size;
3183 * FNV-1a hash each octet of the string
3186 /* xor the bottom with the current octet */
3187 hval ^= (mdb_hash_t)*s++;
3189 /* multiply by the 64 bit FNV magic prime mod 2^64 */
3190 hval += (hval << 1) + (hval << 4) + (hval << 5) +
3191 (hval << 7) + (hval << 8) + (hval << 40);
3193 /* return our new hash value */
3197 /** Hash the string and output the hash in hex.
3198 * @param[in] str string to hash
3199 * @param[out] hexbuf an array of 17 chars to hold the hash
3202 mdb_hash_hex(MDB_val *val, char *hexbuf)
3205 mdb_hash_t h = mdb_hash_val(val, MDB_HASH_INIT);
3206 for (i=0; i<8; i++) {
3207 hexbuf += sprintf(hexbuf, "%02x", (unsigned int)h & 0xff);
3213 /** Open and/or initialize the lock region for the environment.
3214 * @param[in] env The MDB environment.
3215 * @param[in] lpath The pathname of the file used for the lock region.
3216 * @param[in] mode The Unix permissions for the file, if we create it.
3217 * @param[out] excl Resulting file lock type: -1 none, 0 shared, 1 exclusive
3218 * @param[in,out] excl In -1, out lock type: -1 none, 0 shared, 1 exclusive
3219 * @return 0 on success, non-zero on failure.
3222 mdb_env_setup_locks(MDB_env *env, char *lpath, int mode, int *excl)
3225 # define MDB_ERRCODE_ROFS ERROR_WRITE_PROTECT
3227 # define MDB_ERRCODE_ROFS EROFS
3228 #ifdef O_CLOEXEC /* Linux: Open file and set FD_CLOEXEC atomically */
3229 # define MDB_CLOEXEC O_CLOEXEC
3232 # define MDB_CLOEXEC 0
3239 env->me_lfd = CreateFile(lpath, GENERIC_READ|GENERIC_WRITE,
3240 FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, OPEN_ALWAYS,
3241 FILE_ATTRIBUTE_NORMAL, NULL);
3243 env->me_lfd = open(lpath, O_RDWR|O_CREAT|MDB_CLOEXEC, mode);
3245 if (env->me_lfd == INVALID_HANDLE_VALUE) {
3247 if (rc == MDB_ERRCODE_ROFS && (env->me_flags & MDB_RDONLY)) {
3252 #if ! ((MDB_CLOEXEC) || defined(_WIN32))
3253 /* Lose record locks when exec*() */
3254 if ((fdflags = fcntl(env->me_lfd, F_GETFD) | FD_CLOEXEC) >= 0)
3255 fcntl(env->me_lfd, F_SETFD, fdflags);
3258 if (!(env->me_flags & MDB_NOTLS)) {
3259 rc = pthread_key_create(&env->me_txkey, mdb_env_reader_dest);
3262 env->me_flags |= MDB_ENV_TXKEY;
3264 /* Windows TLS callbacks need help finding their TLS info. */
3265 if (mdb_tls_nkeys >= MAX_TLS_KEYS) {
3269 mdb_tls_keys[mdb_tls_nkeys++] = env->me_txkey;
3273 /* Try to get exclusive lock. If we succeed, then
3274 * nobody is using the lock region and we should initialize it.
3276 if ((rc = mdb_env_excl_lock(env, excl))) goto fail;
3279 size = GetFileSize(env->me_lfd, NULL);
3281 size = lseek(env->me_lfd, 0, SEEK_END);
3283 rsize = (env->me_maxreaders-1) * sizeof(MDB_reader) + sizeof(MDB_txninfo);
3284 if (size < rsize && *excl > 0) {
3286 SetFilePointer(env->me_lfd, rsize, NULL, 0);
3287 if (!SetEndOfFile(env->me_lfd)) goto fail_errno;
3289 if (ftruncate(env->me_lfd, rsize) != 0) goto fail_errno;
3293 size = rsize - sizeof(MDB_txninfo);
3294 env->me_maxreaders = size/sizeof(MDB_reader) + 1;
3299 mh = CreateFileMapping(env->me_lfd, NULL, PAGE_READWRITE,
3301 if (!mh) goto fail_errno;
3302 env->me_txns = MapViewOfFileEx(mh, FILE_MAP_WRITE, 0, 0, rsize, NULL);
3304 if (!env->me_txns) goto fail_errno;
3306 void *m = mmap(NULL, rsize, PROT_READ|PROT_WRITE, MAP_SHARED,
3308 if (m == MAP_FAILED) goto fail_errno;
3314 BY_HANDLE_FILE_INFORMATION stbuf;
3323 if (!mdb_sec_inited) {
3324 InitializeSecurityDescriptor(&mdb_null_sd,
3325 SECURITY_DESCRIPTOR_REVISION);
3326 SetSecurityDescriptorDacl(&mdb_null_sd, TRUE, 0, FALSE);
3327 mdb_all_sa.nLength = sizeof(SECURITY_ATTRIBUTES);
3328 mdb_all_sa.bInheritHandle = FALSE;
3329 mdb_all_sa.lpSecurityDescriptor = &mdb_null_sd;
3332 if (!GetFileInformationByHandle(env->me_lfd, &stbuf)) goto fail_errno;
3333 idbuf.volume = stbuf.dwVolumeSerialNumber;
3334 idbuf.nhigh = stbuf.nFileIndexHigh;
3335 idbuf.nlow = stbuf.nFileIndexLow;
3336 val.mv_data = &idbuf;
3337 val.mv_size = sizeof(idbuf);
3338 mdb_hash_hex(&val, hexbuf);
3339 sprintf(env->me_txns->mti_rmname, "Global\\MDBr%s", hexbuf);
3340 sprintf(env->me_txns->mti_wmname, "Global\\MDBw%s", hexbuf);
3341 env->me_rmutex = CreateMutex(&mdb_all_sa, FALSE, env->me_txns->mti_rmname);
3342 if (!env->me_rmutex) goto fail_errno;
3343 env->me_wmutex = CreateMutex(&mdb_all_sa, FALSE, env->me_txns->mti_wmname);
3344 if (!env->me_wmutex) goto fail_errno;
3345 #elif defined(MDB_USE_POSIX_SEM)
3354 if (fstat(env->me_lfd, &stbuf)) goto fail_errno;
3355 idbuf.dev = stbuf.st_dev;
3356 idbuf.ino = stbuf.st_ino;
3357 val.mv_data = &idbuf;
3358 val.mv_size = sizeof(idbuf);
3359 mdb_hash_hex(&val, hexbuf);
3360 sprintf(env->me_txns->mti_rmname, "/MDBr%s", hexbuf);
3361 sprintf(env->me_txns->mti_wmname, "/MDBw%s", hexbuf);
3362 /* Clean up after a previous run, if needed: Try to
3363 * remove both semaphores before doing anything else.
3365 sem_unlink(env->me_txns->mti_rmname);
3366 sem_unlink(env->me_txns->mti_wmname);
3367 env->me_rmutex = sem_open(env->me_txns->mti_rmname,
3368 O_CREAT|O_EXCL, mode, 1);
3369 if (env->me_rmutex == SEM_FAILED) goto fail_errno;
3370 env->me_wmutex = sem_open(env->me_txns->mti_wmname,
3371 O_CREAT|O_EXCL, mode, 1);
3372 if (env->me_wmutex == SEM_FAILED) goto fail_errno;
3373 #else /* MDB_USE_POSIX_SEM */
3374 pthread_mutexattr_t mattr;
3376 if ((rc = pthread_mutexattr_init(&mattr))
3377 || (rc = pthread_mutexattr_setpshared(&mattr, PTHREAD_PROCESS_SHARED))
3378 || (rc = pthread_mutex_init(&env->me_txns->mti_mutex, &mattr))
3379 || (rc = pthread_mutex_init(&env->me_txns->mti_wmutex, &mattr)))
3381 pthread_mutexattr_destroy(&mattr);
3382 #endif /* _WIN32 || MDB_USE_POSIX_SEM */
3384 env->me_txns->mti_version = MDB_VERSION;
3385 env->me_txns->mti_magic = MDB_MAGIC;
3386 env->me_txns->mti_txnid = 0;
3387 env->me_txns->mti_numreaders = 0;
3390 if (env->me_txns->mti_magic != MDB_MAGIC) {
3391 DPUTS("lock region has invalid magic");
3395 if (env->me_txns->mti_version != MDB_VERSION) {
3396 DPRINTF("lock region is version %u, expected version %u",
3397 env->me_txns->mti_version, MDB_VERSION);
3398 rc = MDB_VERSION_MISMATCH;
3402 if (rc != EACCES && rc != EAGAIN) {
3406 env->me_rmutex = OpenMutex(SYNCHRONIZE, FALSE, env->me_txns->mti_rmname);
3407 if (!env->me_rmutex) goto fail_errno;
3408 env->me_wmutex = OpenMutex(SYNCHRONIZE, FALSE, env->me_txns->mti_wmname);
3409 if (!env->me_wmutex) goto fail_errno;
3410 #elif defined(MDB_USE_POSIX_SEM)
3411 env->me_rmutex = sem_open(env->me_txns->mti_rmname, 0);
3412 if (env->me_rmutex == SEM_FAILED) goto fail_errno;
3413 env->me_wmutex = sem_open(env->me_txns->mti_wmname, 0);
3414 if (env->me_wmutex == SEM_FAILED) goto fail_errno;
3425 /** The name of the lock file in the DB environment */
3426 #define LOCKNAME "/lock.mdb"
3427 /** The name of the data file in the DB environment */
3428 #define DATANAME "/data.mdb"
3429 /** The suffix of the lock file when no subdir is used */
3430 #define LOCKSUFF "-lock"
3431 /** Only a subset of the @ref mdb_env flags can be changed
3432 * at runtime. Changing other flags requires closing the
3433 * environment and re-opening it with the new flags.
3435 #define CHANGEABLE (MDB_NOSYNC|MDB_NOMETASYNC|MDB_MAPASYNC)
3436 #define CHANGELESS (MDB_FIXEDMAP|MDB_NOSUBDIR|MDB_RDONLY|MDB_WRITEMAP|MDB_NOTLS)
3439 mdb_env_open(MDB_env *env, const char *path, unsigned int flags, mdb_mode_t mode)
3441 int oflags, rc, len, excl = -1;
3442 char *lpath, *dpath;
3444 if (env->me_fd!=INVALID_HANDLE_VALUE || (flags & ~(CHANGEABLE|CHANGELESS)))
3448 if (flags & MDB_NOSUBDIR) {
3449 rc = len + sizeof(LOCKSUFF) + len + 1;
3451 rc = len + sizeof(LOCKNAME) + len + sizeof(DATANAME);
3456 if (flags & MDB_NOSUBDIR) {
3457 dpath = lpath + len + sizeof(LOCKSUFF);
3458 sprintf(lpath, "%s" LOCKSUFF, path);
3459 strcpy(dpath, path);
3461 dpath = lpath + len + sizeof(LOCKNAME);
3462 sprintf(lpath, "%s" LOCKNAME, path);
3463 sprintf(dpath, "%s" DATANAME, path);
3467 flags |= env->me_flags;
3468 if (flags & MDB_RDONLY) {
3469 /* silently ignore WRITEMAP when we're only getting read access */
3470 flags &= ~MDB_WRITEMAP;
3472 if (!((env->me_free_pgs = mdb_midl_alloc()) &&
3473 (env->me_dirty_list = calloc(MDB_IDL_UM_SIZE, sizeof(MDB_ID2)))))
3476 env->me_flags = flags |= MDB_ENV_ACTIVE;
3480 env->me_path = strdup(path);
3481 env->me_dbxs = calloc(env->me_maxdbs, sizeof(MDB_dbx));
3482 env->me_dbflags = calloc(env->me_maxdbs, sizeof(uint16_t));
3483 if (!(env->me_dbxs && env->me_path && env->me_dbflags)) {
3488 rc = mdb_env_setup_locks(env, lpath, mode, &excl);
3493 if (F_ISSET(flags, MDB_RDONLY)) {
3494 oflags = GENERIC_READ;
3495 len = OPEN_EXISTING;
3497 oflags = GENERIC_READ|GENERIC_WRITE;
3500 mode = FILE_ATTRIBUTE_NORMAL;
3501 env->me_fd = CreateFile(dpath, oflags, FILE_SHARE_READ|FILE_SHARE_WRITE,
3502 NULL, len, mode, NULL);
3504 if (F_ISSET(flags, MDB_RDONLY))
3507 oflags = O_RDWR | O_CREAT;
3509 env->me_fd = open(dpath, oflags, mode);
3511 if (env->me_fd == INVALID_HANDLE_VALUE) {
3516 if ((rc = mdb_env_open2(env)) == MDB_SUCCESS) {
3517 if (flags & (MDB_RDONLY|MDB_WRITEMAP)) {
3518 env->me_mfd = env->me_fd;
3520 /* Synchronous fd for meta writes. Needed even with
3521 * MDB_NOSYNC/MDB_NOMETASYNC, in case these get reset.
3524 env->me_mfd = CreateFile(dpath, oflags,
3525 FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, len,
3526 mode | FILE_FLAG_WRITE_THROUGH, NULL);
3528 env->me_mfd = open(dpath, oflags | MDB_DSYNC, mode);
3530 if (env->me_mfd == INVALID_HANDLE_VALUE) {
3535 DPRINTF("opened dbenv %p", (void *) env);
3537 rc = mdb_env_share_locks(env, &excl);
3543 mdb_env_close0(env, excl);
3549 /** Destroy resources from mdb_env_open() and clear our readers */
3551 mdb_env_close0(MDB_env *env, int excl)
3555 if (!(env->me_flags & MDB_ENV_ACTIVE))
3558 free(env->me_dbflags);
3561 free(env->me_dirty_list);
3562 if (env->me_free_pgs)
3563 mdb_midl_free(env->me_free_pgs);
3565 if (env->me_flags & MDB_ENV_TXKEY) {
3566 pthread_key_delete(env->me_txkey);
3568 /* Delete our key from the global list */
3569 for (i=0; i<mdb_tls_nkeys; i++)
3570 if (mdb_tls_keys[i] == env->me_txkey) {
3571 mdb_tls_keys[i] = mdb_tls_keys[mdb_tls_nkeys-1];
3579 munmap(env->me_map, env->me_mapsize);
3581 if (env->me_mfd != env->me_fd && env->me_mfd != INVALID_HANDLE_VALUE)
3583 if (env->me_fd != INVALID_HANDLE_VALUE)
3586 pid_t pid = env->me_pid;
3587 /* Clearing readers is done in this function because
3588 * me_txkey with its destructor must be disabled first.
3590 for (i = env->me_numreaders; --i >= 0; )
3591 if (env->me_txns->mti_readers[i].mr_pid == pid)
3592 env->me_txns->mti_readers[i].mr_pid = 0;
3594 if (env->me_rmutex) {
3595 CloseHandle(env->me_rmutex);
3596 if (env->me_wmutex) CloseHandle(env->me_wmutex);
3598 /* Windows automatically destroys the mutexes when
3599 * the last handle closes.
3601 #elif defined(MDB_USE_POSIX_SEM)
3602 if (env->me_rmutex != SEM_FAILED) {
3603 sem_close(env->me_rmutex);
3604 if (env->me_wmutex != SEM_FAILED)
3605 sem_close(env->me_wmutex);
3606 /* If we have the filelock: If we are the
3607 * only remaining user, clean up semaphores.
3610 mdb_env_excl_lock(env, &excl);
3612 sem_unlink(env->me_txns->mti_rmname);
3613 sem_unlink(env->me_txns->mti_wmname);
3617 munmap((void *)env->me_txns, (env->me_maxreaders-1)*sizeof(MDB_reader)+sizeof(MDB_txninfo));
3619 if (env->me_lfd != INVALID_HANDLE_VALUE) {
3622 /* Unlock the lockfile. Windows would have unlocked it
3623 * after closing anyway, but not necessarily at once.
3625 UnlockFile(env->me_lfd, 0, 0, 1, 0);
3631 env->me_flags &= ~(MDB_ENV_ACTIVE|MDB_ENV_TXKEY);
3635 mdb_env_copy(MDB_env *env, const char *path)
3637 MDB_txn *txn = NULL;
3641 HANDLE newfd = INVALID_HANDLE_VALUE;
3643 if (env->me_flags & MDB_NOSUBDIR) {
3644 lpath = (char *)path;
3647 len += sizeof(DATANAME);
3648 lpath = malloc(len);
3651 sprintf(lpath, "%s" DATANAME, path);
3654 /* The destination path must exist, but the destination file must not.
3655 * We don't want the OS to cache the writes, since the source data is
3656 * already in the OS cache.
3659 newfd = CreateFile(lpath, GENERIC_WRITE, 0, NULL, CREATE_NEW,
3660 FILE_FLAG_NO_BUFFERING|FILE_FLAG_WRITE_THROUGH, NULL);
3662 newfd = open(lpath, O_WRONLY|O_CREAT|O_EXCL
3668 if (!(env->me_flags & MDB_NOSUBDIR))
3670 if (newfd == INVALID_HANDLE_VALUE) {
3675 #ifdef F_NOCACHE /* __APPLE__ */
3676 rc = fcntl(newfd, F_NOCACHE, 1);
3683 /* Do the lock/unlock of the reader mutex before starting the
3684 * write txn. Otherwise other read txns could block writers.
3686 rc = mdb_txn_begin(env, NULL, MDB_RDONLY, &txn);
3691 /* We must start the actual read txn after blocking writers */
3692 mdb_txn_reset0(txn);
3694 /* Temporarily block writers until we snapshot the meta pages */
3697 rc = mdb_txn_renew0(txn);
3699 UNLOCK_MUTEX_W(env);
3704 wsize = env->me_psize * 2;
3708 rc = WriteFile(newfd, env->me_map, wsize, &len, NULL);
3709 rc = (len == wsize) ? MDB_SUCCESS : ErrCode();
3712 rc = write(newfd, env->me_map, wsize);
3713 rc = (rc == (int)wsize) ? MDB_SUCCESS : ErrCode();
3716 UNLOCK_MUTEX_W(env);
3721 ptr = env->me_map + wsize;
3722 wsize = txn->mt_next_pgno * env->me_psize - wsize;
3723 #define MAX_WRITE 2147483648U
3727 if (wsize > MAX_WRITE)
3731 rc = WriteFile(newfd, ptr, w2, &len, NULL);
3732 rc = (len == w2) ? MDB_SUCCESS : ErrCode();
3741 if (wsize > MAX_WRITE)
3745 wres = write(newfd, ptr, w2);
3746 rc = (wres > 0) ? MDB_SUCCESS : ErrCode();
3755 if (newfd != INVALID_HANDLE_VALUE)
3762 mdb_env_close(MDB_env *env)
3770 for (i = env->me_maxdbs; --i > MAIN_DBI; )
3771 free(env->me_dbxs[i].md_name.mv_data);
3773 VGMEMP_DESTROY(env);
3774 while ((dp = env->me_dpages) != NULL) {
3775 VGMEMP_DEFINED(&dp->mp_next, sizeof(dp->mp_next));
3776 env->me_dpages = dp->mp_next;
3780 mdb_env_close0(env, 0);
3784 /** Compare two items pointing at aligned size_t's */
3786 mdb_cmp_long(const MDB_val *a, const MDB_val *b)
3788 return (*(size_t *)a->mv_data < *(size_t *)b->mv_data) ? -1 :
3789 *(size_t *)a->mv_data > *(size_t *)b->mv_data;
3792 /** Compare two items pointing at aligned int's */
3794 mdb_cmp_int(const MDB_val *a, const MDB_val *b)
3796 return (*(unsigned int *)a->mv_data < *(unsigned int *)b->mv_data) ? -1 :
3797 *(unsigned int *)a->mv_data > *(unsigned int *)b->mv_data;
3800 /** Compare two items pointing at ints of unknown alignment.
3801 * Nodes and keys are guaranteed to be 2-byte aligned.
3804 mdb_cmp_cint(const MDB_val *a, const MDB_val *b)
3806 #if BYTE_ORDER == LITTLE_ENDIAN
3807 unsigned short *u, *c;
3810 u = (unsigned short *) ((char *) a->mv_data + a->mv_size);
3811 c = (unsigned short *) ((char *) b->mv_data + a->mv_size);
3814 } while(!x && u > (unsigned short *)a->mv_data);
3817 return memcmp(a->mv_data, b->mv_data, a->mv_size);
3821 /** Compare two items lexically */
3823 mdb_cmp_memn(const MDB_val *a, const MDB_val *b)
3830 len_diff = (ssize_t) a->mv_size - (ssize_t) b->mv_size;
3836 diff = memcmp(a->mv_data, b->mv_data, len);
3837 return diff ? diff : len_diff<0 ? -1 : len_diff;
3840 /** Compare two items in reverse byte order */
3842 mdb_cmp_memnr(const MDB_val *a, const MDB_val *b)
3844 const unsigned char *p1, *p2, *p1_lim;
3848 p1_lim = (const unsigned char *)a->mv_data;
3849 p1 = (const unsigned char *)a->mv_data + a->mv_size;
3850 p2 = (const unsigned char *)b->mv_data + b->mv_size;
3852 len_diff = (ssize_t) a->mv_size - (ssize_t) b->mv_size;
3858 while (p1 > p1_lim) {
3859 diff = *--p1 - *--p2;
3863 return len_diff<0 ? -1 : len_diff;
3866 /** Search for key within a page, using binary search.
3867 * Returns the smallest entry larger or equal to the key.
3868 * If exactp is non-null, stores whether the found entry was an exact match
3869 * in *exactp (1 or 0).
3870 * Updates the cursor index with the index of the found entry.
3871 * If no entry larger or equal to the key is found, returns NULL.
3874 mdb_node_search(MDB_cursor *mc, MDB_val *key, int *exactp)
3876 unsigned int i = 0, nkeys;
3879 MDB_page *mp = mc->mc_pg[mc->mc_top];
3880 MDB_node *node = NULL;
3885 nkeys = NUMKEYS(mp);
3890 COPY_PGNO(pgno, mp->mp_pgno);
3891 DPRINTF("searching %u keys in %s %spage %zu",
3892 nkeys, IS_LEAF(mp) ? "leaf" : "branch", IS_SUBP(mp) ? "sub-" : "",
3899 low = IS_LEAF(mp) ? 0 : 1;
3901 cmp = mc->mc_dbx->md_cmp;
3903 /* Branch pages have no data, so if using integer keys,
3904 * alignment is guaranteed. Use faster mdb_cmp_int.
3906 if (cmp == mdb_cmp_cint && IS_BRANCH(mp)) {
3907 if (NODEPTR(mp, 1)->mn_ksize == sizeof(size_t))
3914 nodekey.mv_size = mc->mc_db->md_pad;
3915 node = NODEPTR(mp, 0); /* fake */
3916 while (low <= high) {
3917 i = (low + high) >> 1;
3918 nodekey.mv_data = LEAF2KEY(mp, i, nodekey.mv_size);
3919 rc = cmp(key, &nodekey);
3920 DPRINTF("found leaf index %u [%s], rc = %i",
3921 i, DKEY(&nodekey), rc);
3930 while (low <= high) {
3931 i = (low + high) >> 1;
3933 node = NODEPTR(mp, i);
3934 nodekey.mv_size = NODEKSZ(node);
3935 nodekey.mv_data = NODEKEY(node);
3937 rc = cmp(key, &nodekey);
3940 DPRINTF("found leaf index %u [%s], rc = %i",
3941 i, DKEY(&nodekey), rc);
3943 DPRINTF("found branch index %u [%s -> %zu], rc = %i",
3944 i, DKEY(&nodekey), NODEPGNO(node), rc);
3955 if (rc > 0) { /* Found entry is less than the key. */
3956 i++; /* Skip to get the smallest entry larger than key. */
3958 node = NODEPTR(mp, i);
3961 *exactp = (rc == 0);
3962 /* store the key index */
3963 mc->mc_ki[mc->mc_top] = i;
3965 /* There is no entry larger or equal to the key. */
3968 /* nodeptr is fake for LEAF2 */
3974 mdb_cursor_adjust(MDB_cursor *mc, func)
3978 for (m2 = mc->mc_txn->mt_cursors[mc->mc_dbi]; m2; m2=m2->mc_next) {
3979 if (m2->mc_pg[m2->mc_top] == mc->mc_pg[mc->mc_top]) {
3986 /** Pop a page off the top of the cursor's stack. */
3988 mdb_cursor_pop(MDB_cursor *mc)
3991 #ifndef MDB_DEBUG_SKIP
3992 MDB_page *top = mc->mc_pg[mc->mc_top];
3998 DPRINTF("popped page %zu off db %u cursor %p", top->mp_pgno,
3999 mc->mc_dbi, (void *) mc);
4003 /** Push a page onto the top of the cursor's stack. */
4005 mdb_cursor_push(MDB_cursor *mc, MDB_page *mp)
4007 DPRINTF("pushing page %zu on db %u cursor %p", mp->mp_pgno,
4008 mc->mc_dbi, (void *) mc);
4010 if (mc->mc_snum >= CURSOR_STACK) {
4011 assert(mc->mc_snum < CURSOR_STACK);
4012 return MDB_CURSOR_FULL;
4015 mc->mc_top = mc->mc_snum++;
4016 mc->mc_pg[mc->mc_top] = mp;
4017 mc->mc_ki[mc->mc_top] = 0;
4022 /** Find the address of the page corresponding to a given page number.
4023 * @param[in] txn the transaction for this access.
4024 * @param[in] pgno the page number for the page to retrieve.
4025 * @param[out] ret address of a pointer where the page's address will be stored.
4026 * @return 0 on success, non-zero on failure.
4029 mdb_page_get(MDB_txn *txn, pgno_t pgno, MDB_page **ret)
4033 if (!((txn->mt_flags & MDB_TXN_RDONLY) |
4034 (txn->mt_env->me_flags & MDB_WRITEMAP)))
4038 MDB_ID2L dl = tx2->mt_u.dirty_list;
4040 unsigned x = mdb_mid2l_search(dl, pgno);
4041 if (x <= dl[0].mid && dl[x].mid == pgno) {
4046 } while ((tx2 = tx2->mt_parent) != NULL);
4049 if (pgno < txn->mt_next_pgno) {
4050 p = (MDB_page *)(txn->mt_env->me_map + txn->mt_env->me_psize * pgno);
4052 DPRINTF("page %zu not found", pgno);
4058 return (p != NULL) ? MDB_SUCCESS : MDB_PAGE_NOTFOUND;
4061 /** Search for the page a given key should be in.
4062 * Pushes parent pages on the cursor stack. This function continues a
4063 * search on a cursor that has already been initialized. (Usually by
4064 * #mdb_page_search() but also by #mdb_node_move().)
4065 * @param[in,out] mc the cursor for this operation.
4066 * @param[in] key the key to search for. If NULL, search for the lowest
4067 * page. (This is used by #mdb_cursor_first().)
4068 * @param[in] flags If MDB_PS_MODIFY set, visited pages are updated with new page numbers.
4069 * If MDB_PS_ROOTONLY set, just fetch root node, no further lookups.
4070 * @return 0 on success, non-zero on failure.
4073 mdb_page_search_root(MDB_cursor *mc, MDB_val *key, int modify)
4075 MDB_page *mp = mc->mc_pg[mc->mc_top];
4080 while (IS_BRANCH(mp)) {
4084 DPRINTF("branch page %zu has %u keys", mp->mp_pgno, NUMKEYS(mp));
4085 assert(NUMKEYS(mp) > 1);
4086 DPRINTF("found index 0 to page %zu", NODEPGNO(NODEPTR(mp, 0)));
4088 if (key == NULL) /* Initialize cursor to first page. */
4090 else if (key->mv_size > MDB_MAXKEYSIZE && key->mv_data == NULL) {
4091 /* cursor to last page */
4095 node = mdb_node_search(mc, key, &exact);
4097 i = NUMKEYS(mp) - 1;
4099 i = mc->mc_ki[mc->mc_top];
4108 DPRINTF("following index %u for key [%s]",
4110 assert(i < NUMKEYS(mp));
4111 node = NODEPTR(mp, i);
4113 if ((rc = mdb_page_get(mc->mc_txn, NODEPGNO(node), &mp)))
4116 mc->mc_ki[mc->mc_top] = i;
4117 if ((rc = mdb_cursor_push(mc, mp)))
4121 if ((rc = mdb_page_touch(mc)) != 0)
4123 mp = mc->mc_pg[mc->mc_top];
4128 DPRINTF("internal error, index points to a %02X page!?",
4130 return MDB_CORRUPTED;
4133 DPRINTF("found leaf page %zu for key [%s]", mp->mp_pgno,
4134 key ? DKEY(key) : NULL);
4139 /** Search for the lowest key under the current branch page.
4140 * This just bypasses a NUMKEYS check in the current page
4141 * before calling mdb_page_search_root(), because the callers
4142 * are all in situations where the current page is known to
4146 mdb_page_search_lowest(MDB_cursor *mc)
4148 MDB_page *mp = mc->mc_pg[mc->mc_top];
4149 MDB_node *node = NODEPTR(mp, 0);
4152 if ((rc = mdb_page_get(mc->mc_txn, NODEPGNO(node), &mp)))
4155 mc->mc_ki[mc->mc_top] = 0;
4156 if ((rc = mdb_cursor_push(mc, mp)))
4158 return mdb_page_search_root(mc, NULL, 0);
4161 /** Search for the page a given key should be in.
4162 * Pushes parent pages on the cursor stack. This function just sets up
4163 * the search; it finds the root page for \b mc's database and sets this
4164 * as the root of the cursor's stack. Then #mdb_page_search_root() is
4165 * called to complete the search.
4166 * @param[in,out] mc the cursor for this operation.
4167 * @param[in] key the key to search for. If NULL, search for the lowest
4168 * page. (This is used by #mdb_cursor_first().)
4169 * @param[in] modify If true, visited pages are updated with new page numbers.
4170 * @return 0 on success, non-zero on failure.
4173 mdb_page_search(MDB_cursor *mc, MDB_val *key, int flags)
4178 /* Make sure the txn is still viable, then find the root from
4179 * the txn's db table.
4181 if (F_ISSET(mc->mc_txn->mt_flags, MDB_TXN_ERROR)) {
4182 DPUTS("transaction has failed, must abort");
4185 /* Make sure we're using an up-to-date root */
4186 if (mc->mc_dbi > MAIN_DBI) {
4187 if ((*mc->mc_dbflag & DB_STALE) ||
4188 ((flags & MDB_PS_MODIFY) && !(*mc->mc_dbflag & DB_DIRTY))) {
4190 unsigned char dbflag = 0;
4191 mdb_cursor_init(&mc2, mc->mc_txn, MAIN_DBI, NULL);
4192 rc = mdb_page_search(&mc2, &mc->mc_dbx->md_name, flags & MDB_PS_MODIFY);
4195 if (*mc->mc_dbflag & DB_STALE) {
4199 MDB_node *leaf = mdb_node_search(&mc2,
4200 &mc->mc_dbx->md_name, &exact);
4202 return MDB_NOTFOUND;
4203 mdb_node_read(mc->mc_txn, leaf, &data);
4204 memcpy(&flags, ((char *) data.mv_data + offsetof(MDB_db, md_flags)),
4206 /* The txn may not know this DBI, or another process may
4207 * have dropped and recreated the DB with other flags.
4209 if ((mc->mc_db->md_flags & PERSISTENT_FLAGS) != flags)
4210 return MDB_INCOMPATIBLE;
4211 memcpy(mc->mc_db, data.mv_data, sizeof(MDB_db));
4213 if (flags & MDB_PS_MODIFY)
4215 *mc->mc_dbflag &= ~DB_STALE;
4216 *mc->mc_dbflag |= dbflag;
4219 root = mc->mc_db->md_root;
4221 if (root == P_INVALID) { /* Tree is empty. */
4222 DPUTS("tree is empty");
4223 return MDB_NOTFOUND;
4228 if (!mc->mc_pg[0] || mc->mc_pg[0]->mp_pgno != root)
4229 if ((rc = mdb_page_get(mc->mc_txn, root, &mc->mc_pg[0])))
4235 DPRINTF("db %u root page %zu has flags 0x%X",
4236 mc->mc_dbi, root, mc->mc_pg[0]->mp_flags);
4238 if (flags & MDB_PS_MODIFY) {
4239 if ((rc = mdb_page_touch(mc)))
4243 if (flags & MDB_PS_ROOTONLY)
4246 return mdb_page_search_root(mc, key, flags);
4249 /** Return the data associated with a given node.
4250 * @param[in] txn The transaction for this operation.
4251 * @param[in] leaf The node being read.
4252 * @param[out] data Updated to point to the node's data.
4253 * @return 0 on success, non-zero on failure.
4256 mdb_node_read(MDB_txn *txn, MDB_node *leaf, MDB_val *data)
4258 MDB_page *omp; /* overflow page */
4262 if (!F_ISSET(leaf->mn_flags, F_BIGDATA)) {
4263 data->mv_size = NODEDSZ(leaf);
4264 data->mv_data = NODEDATA(leaf);
4268 /* Read overflow data.
4270 data->mv_size = NODEDSZ(leaf);
4271 memcpy(&pgno, NODEDATA(leaf), sizeof(pgno));
4272 if ((rc = mdb_page_get(txn, pgno, &omp))) {
4273 DPRINTF("read overflow page %zu failed", pgno);
4276 data->mv_data = METADATA(omp);
4282 mdb_get(MDB_txn *txn, MDB_dbi dbi,
4283 MDB_val *key, MDB_val *data)
4292 DPRINTF("===> get db %u key [%s]", dbi, DKEY(key));
4294 if (txn == NULL || !dbi || dbi >= txn->mt_numdbs || !(txn->mt_dbflags[dbi] & DB_VALID))
4297 if (key->mv_size == 0 || key->mv_size > MDB_MAXKEYSIZE) {
4301 mdb_cursor_init(&mc, txn, dbi, &mx);
4302 return mdb_cursor_set(&mc, key, data, MDB_SET, &exact);
4305 /** Find a sibling for a page.
4306 * Replaces the page at the top of the cursor's stack with the
4307 * specified sibling, if one exists.
4308 * @param[in] mc The cursor for this operation.
4309 * @param[in] move_right Non-zero if the right sibling is requested,
4310 * otherwise the left sibling.
4311 * @return 0 on success, non-zero on failure.
4314 mdb_cursor_sibling(MDB_cursor *mc, int move_right)
4320 if (mc->mc_snum < 2) {
4321 return MDB_NOTFOUND; /* root has no siblings */
4325 DPRINTF("parent page is page %zu, index %u",
4326 mc->mc_pg[mc->mc_top]->mp_pgno, mc->mc_ki[mc->mc_top]);
4328 if (move_right ? (mc->mc_ki[mc->mc_top] + 1u >= NUMKEYS(mc->mc_pg[mc->mc_top]))
4329 : (mc->mc_ki[mc->mc_top] == 0)) {
4330 DPRINTF("no more keys left, moving to %s sibling",
4331 move_right ? "right" : "left");
4332 if ((rc = mdb_cursor_sibling(mc, move_right)) != MDB_SUCCESS) {
4333 /* undo cursor_pop before returning */
4340 mc->mc_ki[mc->mc_top]++;
4342 mc->mc_ki[mc->mc_top]--;
4343 DPRINTF("just moving to %s index key %u",
4344 move_right ? "right" : "left", mc->mc_ki[mc->mc_top]);
4346 assert(IS_BRANCH(mc->mc_pg[mc->mc_top]));
4348 indx = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
4349 if ((rc = mdb_page_get(mc->mc_txn, NODEPGNO(indx), &mp)))
4352 mdb_cursor_push(mc, mp);
4354 mc->mc_ki[mc->mc_top] = NUMKEYS(mp)-1;
4359 /** Move the cursor to the next data item. */
4361 mdb_cursor_next(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op)
4367 if (mc->mc_flags & C_EOF) {
4368 return MDB_NOTFOUND;
4371 assert(mc->mc_flags & C_INITIALIZED);
4373 mp = mc->mc_pg[mc->mc_top];
4375 if (mc->mc_db->md_flags & MDB_DUPSORT) {
4376 leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
4377 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
4378 if (op == MDB_NEXT || op == MDB_NEXT_DUP) {
4379 rc = mdb_cursor_next(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_NEXT);
4380 if (op != MDB_NEXT || rc == MDB_SUCCESS)
4384 mc->mc_xcursor->mx_cursor.mc_flags &= ~C_INITIALIZED;
4385 if (op == MDB_NEXT_DUP)
4386 return MDB_NOTFOUND;
4390 DPRINTF("cursor_next: top page is %zu in cursor %p", mp->mp_pgno, (void *) mc);
4392 if (mc->mc_ki[mc->mc_top] + 1u >= NUMKEYS(mp)) {
4393 DPUTS("=====> move to next sibling page");
4394 if (mdb_cursor_sibling(mc, 1) != MDB_SUCCESS) {
4395 mc->mc_flags |= C_EOF;
4396 mc->mc_flags &= ~C_INITIALIZED;
4397 return MDB_NOTFOUND;
4399 mp = mc->mc_pg[mc->mc_top];
4400 DPRINTF("next page is %zu, key index %u", mp->mp_pgno, mc->mc_ki[mc->mc_top]);
4402 mc->mc_ki[mc->mc_top]++;
4404 DPRINTF("==> cursor points to page %zu with %u keys, key index %u",
4405 mp->mp_pgno, NUMKEYS(mp), mc->mc_ki[mc->mc_top]);
4408 key->mv_size = mc->mc_db->md_pad;
4409 key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
4413 assert(IS_LEAF(mp));
4414 leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
4416 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
4417 mdb_xcursor_init1(mc, leaf);
4420 if ((rc = mdb_node_read(mc->mc_txn, leaf, data)) != MDB_SUCCESS)
4423 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
4424 rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);
4425 if (rc != MDB_SUCCESS)
4430 MDB_GET_KEY(leaf, key);
4434 /** Move the cursor to the previous data item. */
4436 mdb_cursor_prev(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op)
4442 assert(mc->mc_flags & C_INITIALIZED);
4444 mp = mc->mc_pg[mc->mc_top];
4446 if (mc->mc_db->md_flags & MDB_DUPSORT) {
4447 leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
4448 if (op == MDB_PREV || op == MDB_PREV_DUP) {
4449 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
4450 rc = mdb_cursor_prev(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_PREV);
4451 if (op != MDB_PREV || rc == MDB_SUCCESS)
4454 mc->mc_xcursor->mx_cursor.mc_flags &= ~C_INITIALIZED;
4455 if (op == MDB_PREV_DUP)
4456 return MDB_NOTFOUND;
4461 DPRINTF("cursor_prev: top page is %zu in cursor %p", mp->mp_pgno, (void *) mc);
4463 if (mc->mc_ki[mc->mc_top] == 0) {
4464 DPUTS("=====> move to prev sibling page");
4465 if (mdb_cursor_sibling(mc, 0) != MDB_SUCCESS) {
4466 mc->mc_flags &= ~C_INITIALIZED;
4467 return MDB_NOTFOUND;
4469 mp = mc->mc_pg[mc->mc_top];
4470 mc->mc_ki[mc->mc_top] = NUMKEYS(mp) - 1;
4471 DPRINTF("prev page is %zu, key index %u", mp->mp_pgno, mc->mc_ki[mc->mc_top]);
4473 mc->mc_ki[mc->mc_top]--;
4475 mc->mc_flags &= ~C_EOF;
4477 DPRINTF("==> cursor points to page %zu with %u keys, key index %u",
4478 mp->mp_pgno, NUMKEYS(mp), mc->mc_ki[mc->mc_top]);
4481 key->mv_size = mc->mc_db->md_pad;
4482 key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
4486 assert(IS_LEAF(mp));
4487 leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
4489 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
4490 mdb_xcursor_init1(mc, leaf);
4493 if ((rc = mdb_node_read(mc->mc_txn, leaf, data)) != MDB_SUCCESS)
4496 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
4497 rc = mdb_cursor_last(&mc->mc_xcursor->mx_cursor, data, NULL);
4498 if (rc != MDB_SUCCESS)
4503 MDB_GET_KEY(leaf, key);
4507 /** Set the cursor on a specific data item. */
4509 mdb_cursor_set(MDB_cursor *mc, MDB_val *key, MDB_val *data,
4510 MDB_cursor_op op, int *exactp)
4514 MDB_node *leaf = NULL;
4519 assert(key->mv_size > 0);
4521 /* See if we're already on the right page */
4522 if (mc->mc_flags & C_INITIALIZED) {
4525 mp = mc->mc_pg[mc->mc_top];
4527 mc->mc_ki[mc->mc_top] = 0;
4528 return MDB_NOTFOUND;
4530 if (mp->mp_flags & P_LEAF2) {
4531 nodekey.mv_size = mc->mc_db->md_pad;
4532 nodekey.mv_data = LEAF2KEY(mp, 0, nodekey.mv_size);
4534 leaf = NODEPTR(mp, 0);
4535 MDB_GET_KEY(leaf, &nodekey);
4537 rc = mc->mc_dbx->md_cmp(key, &nodekey);
4539 /* Probably happens rarely, but first node on the page
4540 * was the one we wanted.
4542 mc->mc_ki[mc->mc_top] = 0;
4549 unsigned int nkeys = NUMKEYS(mp);
4551 if (mp->mp_flags & P_LEAF2) {
4552 nodekey.mv_data = LEAF2KEY(mp,
4553 nkeys-1, nodekey.mv_size);
4555 leaf = NODEPTR(mp, nkeys-1);
4556 MDB_GET_KEY(leaf, &nodekey);
4558 rc = mc->mc_dbx->md_cmp(key, &nodekey);
4560 /* last node was the one we wanted */
4561 mc->mc_ki[mc->mc_top] = nkeys-1;
4567 if (mc->mc_ki[mc->mc_top] < NUMKEYS(mp)) {
4568 /* This is definitely the right page, skip search_page */
4569 if (mp->mp_flags & P_LEAF2) {
4570 nodekey.mv_data = LEAF2KEY(mp,
4571 mc->mc_ki[mc->mc_top], nodekey.mv_size);
4573 leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
4574 MDB_GET_KEY(leaf, &nodekey);
4576 rc = mc->mc_dbx->md_cmp(key, &nodekey);
4578 /* current node was the one we wanted */
4588 /* If any parents have right-sibs, search.
4589 * Otherwise, there's nothing further.
4591 for (i=0; i<mc->mc_top; i++)
4593 NUMKEYS(mc->mc_pg[i])-1)
4595 if (i == mc->mc_top) {
4596 /* There are no other pages */
4597 mc->mc_ki[mc->mc_top] = nkeys;
4598 return MDB_NOTFOUND;
4602 /* There are no other pages */
4603 mc->mc_ki[mc->mc_top] = 0;
4604 return MDB_NOTFOUND;
4608 rc = mdb_page_search(mc, key, 0);
4609 if (rc != MDB_SUCCESS)
4612 mp = mc->mc_pg[mc->mc_top];
4613 assert(IS_LEAF(mp));
4616 leaf = mdb_node_search(mc, key, exactp);
4617 if (exactp != NULL && !*exactp) {
4618 /* MDB_SET specified and not an exact match. */
4619 return MDB_NOTFOUND;
4623 DPUTS("===> inexact leaf not found, goto sibling");
4624 if ((rc = mdb_cursor_sibling(mc, 1)) != MDB_SUCCESS)
4625 return rc; /* no entries matched */
4626 mp = mc->mc_pg[mc->mc_top];
4627 assert(IS_LEAF(mp));
4628 leaf = NODEPTR(mp, 0);
4632 mc->mc_flags |= C_INITIALIZED;
4633 mc->mc_flags &= ~C_EOF;
4636 key->mv_size = mc->mc_db->md_pad;
4637 key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
4641 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
4642 mdb_xcursor_init1(mc, leaf);
4645 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
4646 if (op == MDB_SET || op == MDB_SET_KEY || op == MDB_SET_RANGE) {
4647 rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);
4650 if (op == MDB_GET_BOTH) {
4656 rc = mdb_cursor_set(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_SET_RANGE, ex2p);
4657 if (rc != MDB_SUCCESS)
4660 } else if (op == MDB_GET_BOTH || op == MDB_GET_BOTH_RANGE) {
4662 if ((rc = mdb_node_read(mc->mc_txn, leaf, &d2)) != MDB_SUCCESS)
4664 rc = mc->mc_dbx->md_dcmp(data, &d2);
4666 if (op == MDB_GET_BOTH || rc > 0)
4667 return MDB_NOTFOUND;
4672 mc->mc_xcursor->mx_cursor.mc_flags &= ~C_INITIALIZED;
4673 if ((rc = mdb_node_read(mc->mc_txn, leaf, data)) != MDB_SUCCESS)
4678 /* The key already matches in all other cases */
4679 if (op == MDB_SET_RANGE || op == MDB_SET_KEY)
4680 MDB_GET_KEY(leaf, key);
4681 DPRINTF("==> cursor placed on key [%s]", DKEY(key));
4686 /** Move the cursor to the first item in the database. */
4688 mdb_cursor_first(MDB_cursor *mc, MDB_val *key, MDB_val *data)
4693 if (!(mc->mc_flags & C_INITIALIZED) || mc->mc_top) {
4694 rc = mdb_page_search(mc, NULL, 0);
4695 if (rc != MDB_SUCCESS)
4698 assert(IS_LEAF(mc->mc_pg[mc->mc_top]));
4700 leaf = NODEPTR(mc->mc_pg[mc->mc_top], 0);
4701 mc->mc_flags |= C_INITIALIZED;
4702 mc->mc_flags &= ~C_EOF;
4704 mc->mc_ki[mc->mc_top] = 0;
4706 if (IS_LEAF2(mc->mc_pg[mc->mc_top])) {
4707 key->mv_size = mc->mc_db->md_pad;
4708 key->mv_data = LEAF2KEY(mc->mc_pg[mc->mc_top], 0, key->mv_size);
4713 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
4714 mdb_xcursor_init1(mc, leaf);
4715 rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);
4720 mc->mc_xcursor->mx_cursor.mc_flags &= ~C_INITIALIZED;
4721 if ((rc = mdb_node_read(mc->mc_txn, leaf, data)) != MDB_SUCCESS)
4725 MDB_GET_KEY(leaf, key);
4729 /** Move the cursor to the last item in the database. */
4731 mdb_cursor_last(MDB_cursor *mc, MDB_val *key, MDB_val *data)
4736 if (!(mc->mc_flags & C_EOF)) {
4738 if (!(mc->mc_flags & C_INITIALIZED) || mc->mc_top) {
4741 lkey.mv_size = MDB_MAXKEYSIZE+1;
4742 lkey.mv_data = NULL;
4743 rc = mdb_page_search(mc, &lkey, 0);
4744 if (rc != MDB_SUCCESS)
4747 assert(IS_LEAF(mc->mc_pg[mc->mc_top]));
4750 mc->mc_ki[mc->mc_top] = NUMKEYS(mc->mc_pg[mc->mc_top]) - 1;
4751 mc->mc_flags |= C_INITIALIZED|C_EOF;
4752 leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
4754 if (IS_LEAF2(mc->mc_pg[mc->mc_top])) {
4755 key->mv_size = mc->mc_db->md_pad;
4756 key->mv_data = LEAF2KEY(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], key->mv_size);
4761 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
4762 mdb_xcursor_init1(mc, leaf);
4763 rc = mdb_cursor_last(&mc->mc_xcursor->mx_cursor, data, NULL);
4768 mc->mc_xcursor->mx_cursor.mc_flags &= ~C_INITIALIZED;
4769 if ((rc = mdb_node_read(mc->mc_txn, leaf, data)) != MDB_SUCCESS)
4774 MDB_GET_KEY(leaf, key);
4779 mdb_cursor_get(MDB_cursor *mc, MDB_val *key, MDB_val *data,
4788 case MDB_GET_CURRENT:
4789 if (!(mc->mc_flags & C_INITIALIZED)) {
4792 MDB_page *mp = mc->mc_pg[mc->mc_top];
4794 mc->mc_ki[mc->mc_top] = 0;
4800 key->mv_size = mc->mc_db->md_pad;
4801 key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
4803 MDB_node *leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
4804 MDB_GET_KEY(leaf, key);
4806 if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
4807 rc = mdb_cursor_get(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_GET_CURRENT);
4809 rc = mdb_node_read(mc->mc_txn, leaf, data);
4816 case MDB_GET_BOTH_RANGE:
4817 if (data == NULL || mc->mc_xcursor == NULL) {
4825 if (key == NULL || key->mv_size == 0 || key->mv_size > MDB_MAXKEYSIZE) {
4827 } else if (op == MDB_SET_RANGE)
4828 rc = mdb_cursor_set(mc, key, data, op, NULL);
4830 rc = mdb_cursor_set(mc, key, data, op, &exact);
4832 case MDB_GET_MULTIPLE:
4834 !(mc->mc_db->md_flags & MDB_DUPFIXED) ||
4835 !(mc->mc_flags & C_INITIALIZED)) {
4840 if (!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) ||
4841 (mc->mc_xcursor->mx_cursor.mc_flags & C_EOF))
4844 case MDB_NEXT_MULTIPLE:
4846 !(mc->mc_db->md_flags & MDB_DUPFIXED)) {
4850 if (!(mc->mc_flags & C_INITIALIZED))
4851 rc = mdb_cursor_first(mc, key, data);
4853 rc = mdb_cursor_next(mc, key, data, MDB_NEXT_DUP);
4854 if (rc == MDB_SUCCESS) {
4855 if (mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) {
4858 mx = &mc->mc_xcursor->mx_cursor;
4859 data->mv_size = NUMKEYS(mx->mc_pg[mx->mc_top]) *
4861 data->mv_data = METADATA(mx->mc_pg[mx->mc_top]);
4862 mx->mc_ki[mx->mc_top] = NUMKEYS(mx->mc_pg[mx->mc_top])-1;
4870 case MDB_NEXT_NODUP:
4871 if (!(mc->mc_flags & C_INITIALIZED))
4872 rc = mdb_cursor_first(mc, key, data);
4874 rc = mdb_cursor_next(mc, key, data, op);
4878 case MDB_PREV_NODUP:
4879 if (!(mc->mc_flags & C_INITIALIZED)) {
4880 rc = mdb_cursor_last(mc, key, data);
4881 mc->mc_flags |= C_INITIALIZED;
4882 mc->mc_ki[mc->mc_top]++;
4884 rc = mdb_cursor_prev(mc, key, data, op);
4887 rc = mdb_cursor_first(mc, key, data);
4891 !(mc->mc_db->md_flags & MDB_DUPSORT) ||
4892 !(mc->mc_flags & C_INITIALIZED) ||
4893 !(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED)) {
4897 rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);
4900 rc = mdb_cursor_last(mc, key, data);
4904 !(mc->mc_db->md_flags & MDB_DUPSORT) ||
4905 !(mc->mc_flags & C_INITIALIZED) ||
4906 !(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED)) {
4910 rc = mdb_cursor_last(&mc->mc_xcursor->mx_cursor, data, NULL);
4913 DPRINTF("unhandled/unimplemented cursor operation %u", op);
4921 /** Touch all the pages in the cursor stack.
4922 * Makes sure all the pages are writable, before attempting a write operation.
4923 * @param[in] mc The cursor to operate on.
4926 mdb_cursor_touch(MDB_cursor *mc)
4930 if (mc->mc_dbi > MAIN_DBI && !(*mc->mc_dbflag & DB_DIRTY)) {
4933 mdb_cursor_init(&mc2, mc->mc_txn, MAIN_DBI,
4934 mc->mc_txn->mt_dbs[MAIN_DBI].md_flags & MDB_DUPSORT ? &mcx : NULL);
4935 rc = mdb_page_search(&mc2, &mc->mc_dbx->md_name, MDB_PS_MODIFY);
4938 *mc->mc_dbflag |= DB_DIRTY;
4940 for (mc->mc_top = 0; mc->mc_top < mc->mc_snum; mc->mc_top++) {
4941 rc = mdb_page_touch(mc);
4945 mc->mc_top = mc->mc_snum-1;
4950 mdb_cursor_put(MDB_cursor *mc, MDB_val *key, MDB_val *data,
4953 MDB_node *leaf = NULL;
4954 MDB_val xdata, *rdata, dkey;
4957 int do_sub = 0, insert = 0;
4958 unsigned int mcount = 0;
4962 char dbuf[MDB_MAXKEYSIZE+1];
4963 unsigned int nflags;
4966 if (F_ISSET(mc->mc_txn->mt_flags, MDB_TXN_RDONLY))
4969 if (flags != MDB_CURRENT && (key->mv_size == 0 || key->mv_size > MDB_MAXKEYSIZE))
4972 if (F_ISSET(mc->mc_db->md_flags, MDB_DUPSORT) && data->mv_size > MDB_MAXKEYSIZE)
4975 #if SIZE_MAX > MAXDATASIZE
4976 if (data->mv_size > MAXDATASIZE)
4980 DPRINTF("==> put db %u key [%s], size %zu, data size %zu",
4981 mc->mc_dbi, DKEY(key), key ? key->mv_size:0, data->mv_size);
4985 if (flags == MDB_CURRENT) {
4986 if (!(mc->mc_flags & C_INITIALIZED))
4989 } else if (mc->mc_db->md_root == P_INVALID) {
4991 /* new database, write a root leaf page */
4992 DPUTS("allocating new root leaf page");
4993 if ((rc = mdb_page_new(mc, P_LEAF, 1, &np))) {
4997 mdb_cursor_push(mc, np);
4998 mc->mc_db->md_root = np->mp_pgno;
4999 mc->mc_db->md_depth++;
5000 *mc->mc_dbflag |= DB_DIRTY;
5001 if ((mc->mc_db->md_flags & (MDB_DUPSORT|MDB_DUPFIXED))
5003 np->mp_flags |= P_LEAF2;
5004 mc->mc_flags |= C_INITIALIZED;
5010 if (flags & MDB_APPEND) {
5012 rc = mdb_cursor_last(mc, &k2, &d2);
5014 rc = mc->mc_dbx->md_cmp(key, &k2);
5017 mc->mc_ki[mc->mc_top]++;
5019 /* new key is <= last key */
5024 rc = mdb_cursor_set(mc, key, &d2, MDB_SET, &exact);
5026 if ((flags & MDB_NOOVERWRITE) && rc == 0) {
5027 DPRINTF("duplicate key [%s]", DKEY(key));
5029 return MDB_KEYEXIST;
5031 if (rc && rc != MDB_NOTFOUND)
5035 /* Cursor is positioned, now make sure all pages are writable */
5036 rc2 = mdb_cursor_touch(mc);
5041 /* The key already exists */
5042 if (rc == MDB_SUCCESS) {
5043 /* there's only a key anyway, so this is a no-op */
5044 if (IS_LEAF2(mc->mc_pg[mc->mc_top])) {
5045 unsigned int ksize = mc->mc_db->md_pad;
5046 if (key->mv_size != ksize)
5048 if (flags == MDB_CURRENT) {
5049 char *ptr = LEAF2KEY(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], ksize);
5050 memcpy(ptr, key->mv_data, ksize);
5055 leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
5058 if (F_ISSET(mc->mc_db->md_flags, MDB_DUPSORT)) {
5059 /* Was a single item before, must convert now */
5061 if (!F_ISSET(leaf->mn_flags, F_DUPDATA)) {
5062 /* Just overwrite the current item */
5063 if (flags == MDB_CURRENT)
5066 dkey.mv_size = NODEDSZ(leaf);
5067 dkey.mv_data = NODEDATA(leaf);
5068 #if UINT_MAX < SIZE_MAX
5069 if (mc->mc_dbx->md_dcmp == mdb_cmp_int && dkey.mv_size == sizeof(size_t))
5070 #ifdef MISALIGNED_OK
5071 mc->mc_dbx->md_dcmp = mdb_cmp_long;
5073 mc->mc_dbx->md_dcmp = mdb_cmp_cint;
5076 /* if data matches, ignore it */
5077 if (!mc->mc_dbx->md_dcmp(data, &dkey))
5078 return (flags == MDB_NODUPDATA) ? MDB_KEYEXIST : MDB_SUCCESS;
5080 /* create a fake page for the dup items */
5081 memcpy(dbuf, dkey.mv_data, dkey.mv_size);
5082 dkey.mv_data = dbuf;
5083 fp = (MDB_page *)&pbuf;
5084 fp->mp_pgno = mc->mc_pg[mc->mc_top]->mp_pgno;
5085 fp->mp_flags = P_LEAF|P_DIRTY|P_SUBP;
5086 fp->mp_lower = PAGEHDRSZ;
5087 fp->mp_upper = PAGEHDRSZ + dkey.mv_size + data->mv_size;
5088 if (mc->mc_db->md_flags & MDB_DUPFIXED) {
5089 fp->mp_flags |= P_LEAF2;
5090 fp->mp_pad = data->mv_size;
5091 fp->mp_upper += 2 * data->mv_size; /* leave space for 2 more */
5093 fp->mp_upper += 2 * sizeof(indx_t) + 2 * NODESIZE +
5094 (dkey.mv_size & 1) + (data->mv_size & 1);
5096 mdb_node_del(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], 0);
5099 xdata.mv_size = fp->mp_upper;
5104 if (!F_ISSET(leaf->mn_flags, F_SUBDATA)) {
5105 /* See if we need to convert from fake page to subDB */
5107 unsigned int offset;
5110 fp = NODEDATA(leaf);
5111 if (flags == MDB_CURRENT) {
5113 fp->mp_flags |= P_DIRTY;
5114 COPY_PGNO(fp->mp_pgno, mc->mc_pg[mc->mc_top]->mp_pgno);
5115 mc->mc_xcursor->mx_cursor.mc_pg[0] = fp;
5119 if (mc->mc_db->md_flags & MDB_DUPFIXED) {
5120 offset = fp->mp_pad;
5121 if (SIZELEFT(fp) >= offset)
5123 offset *= 4; /* space for 4 more */
5125 offset = NODESIZE + sizeof(indx_t) + data->mv_size;
5127 offset += offset & 1;
5128 if (NODESIZE + sizeof(indx_t) + NODEKSZ(leaf) + NODEDSZ(leaf) +
5129 offset >= mc->mc_txn->mt_env->me_nodemax) {
5130 /* yes, convert it */
5132 if (mc->mc_db->md_flags & MDB_DUPFIXED) {
5133 dummy.md_pad = fp->mp_pad;
5134 dummy.md_flags = MDB_DUPFIXED;
5135 if (mc->mc_db->md_flags & MDB_INTEGERDUP)
5136 dummy.md_flags |= MDB_INTEGERKEY;
5139 dummy.md_branch_pages = 0;
5140 dummy.md_leaf_pages = 1;
5141 dummy.md_overflow_pages = 0;
5142 dummy.md_entries = NUMKEYS(fp);
5144 xdata.mv_size = sizeof(MDB_db);
5145 xdata.mv_data = &dummy;
5146 if ((rc = mdb_page_alloc(mc, 1, &mp)))
5148 offset = mc->mc_txn->mt_env->me_psize - NODEDSZ(leaf);
5149 flags |= F_DUPDATA|F_SUBDATA;
5150 dummy.md_root = mp->mp_pgno;
5152 /* no, just grow it */
5154 xdata.mv_size = NODEDSZ(leaf) + offset;
5155 xdata.mv_data = &pbuf;
5156 mp = (MDB_page *)&pbuf;
5157 mp->mp_pgno = mc->mc_pg[mc->mc_top]->mp_pgno;
5160 mp->mp_flags = fp->mp_flags | P_DIRTY;
5161 mp->mp_pad = fp->mp_pad;
5162 mp->mp_lower = fp->mp_lower;
5163 mp->mp_upper = fp->mp_upper + offset;
5165 memcpy(METADATA(mp), METADATA(fp), NUMKEYS(fp) * fp->mp_pad);
5167 nsize = NODEDSZ(leaf) - fp->mp_upper;
5168 memcpy((char *)mp + mp->mp_upper, (char *)fp + fp->mp_upper, nsize);
5169 for (i=0; i<NUMKEYS(fp); i++)
5170 mp->mp_ptrs[i] = fp->mp_ptrs[i] + offset;
5172 mdb_node_del(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], 0);
5176 /* data is on sub-DB, just store it */
5177 flags |= F_DUPDATA|F_SUBDATA;
5181 /* overflow page overwrites need special handling */
5182 if (F_ISSET(leaf->mn_flags, F_BIGDATA)) {
5185 int ovpages, dpages;
5187 ovpages = OVPAGES(NODEDSZ(leaf), mc->mc_txn->mt_env->me_psize);
5188 dpages = OVPAGES(data->mv_size, mc->mc_txn->mt_env->me_psize);
5189 memcpy(&pg, NODEDATA(leaf), sizeof(pg));
5190 mdb_page_get(mc->mc_txn, pg, &omp);
5191 /* Is the ov page writable and large enough? */
5192 if ((omp->mp_flags & P_DIRTY) && ovpages >= dpages) {
5193 /* yes, overwrite it. Note in this case we don't
5194 * bother to try shrinking the node if the new data
5195 * is smaller than the overflow threshold.
5197 if (F_ISSET(flags, MDB_RESERVE))
5198 data->mv_data = METADATA(omp);
5200 memcpy(METADATA(omp), data->mv_data, data->mv_size);
5203 /* no, free ovpages */
5205 mc->mc_db->md_overflow_pages -= ovpages;
5206 for (i=0; i<ovpages; i++) {
5207 DPRINTF("freed ov page %zu", pg);
5208 mdb_midl_append(&mc->mc_txn->mt_free_pgs, pg);
5212 } else if (NODEDSZ(leaf) == data->mv_size) {
5213 /* same size, just replace it. Note that we could
5214 * also reuse this node if the new data is smaller,
5215 * but instead we opt to shrink the node in that case.
5217 if (F_ISSET(flags, MDB_RESERVE))
5218 data->mv_data = NODEDATA(leaf);
5219 else if (data->mv_size)
5220 memcpy(NODEDATA(leaf), data->mv_data, data->mv_size);
5222 memcpy(NODEKEY(leaf), key->mv_data, key->mv_size);
5225 mdb_node_del(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], 0);
5226 mc->mc_db->md_entries--;
5228 DPRINTF("inserting key at index %i", mc->mc_ki[mc->mc_top]);
5235 nflags = flags & NODE_ADD_FLAGS;
5236 nsize = IS_LEAF2(mc->mc_pg[mc->mc_top]) ? key->mv_size : mdb_leaf_size(mc->mc_txn->mt_env, key, rdata);
5237 if (SIZELEFT(mc->mc_pg[mc->mc_top]) < nsize) {
5238 if (( flags & (F_DUPDATA|F_SUBDATA)) == F_DUPDATA )
5239 nflags &= ~MDB_APPEND;
5241 nflags |= MDB_SPLIT_REPLACE;
5242 rc = mdb_page_split(mc, key, rdata, P_INVALID, nflags);
5244 /* There is room already in this leaf page. */
5245 rc = mdb_node_add(mc, mc->mc_ki[mc->mc_top], key, rdata, 0, nflags);
5246 if (rc == 0 && !do_sub && insert) {
5247 /* Adjust other cursors pointing to mp */
5248 MDB_cursor *m2, *m3;
5249 MDB_dbi dbi = mc->mc_dbi;
5250 unsigned i = mc->mc_top;
5251 MDB_page *mp = mc->mc_pg[i];
5253 if (mc->mc_flags & C_SUB)
5256 for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
5257 if (mc->mc_flags & C_SUB)
5258 m3 = &m2->mc_xcursor->mx_cursor;
5261 if (m3 == mc || m3->mc_snum < mc->mc_snum) continue;
5262 if (m3->mc_pg[i] == mp && m3->mc_ki[i] >= mc->mc_ki[i]) {
5269 if (rc != MDB_SUCCESS)
5270 mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
5272 /* Now store the actual data in the child DB. Note that we're
5273 * storing the user data in the keys field, so there are strict
5274 * size limits on dupdata. The actual data fields of the child
5275 * DB are all zero size.
5282 leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
5283 if (flags & MDB_CURRENT) {
5284 xflags = MDB_CURRENT;
5286 mdb_xcursor_init1(mc, leaf);
5287 xflags = (flags & MDB_NODUPDATA) ? MDB_NOOVERWRITE : 0;
5289 /* converted, write the original data first */
5291 rc = mdb_cursor_put(&mc->mc_xcursor->mx_cursor, &dkey, &xdata, xflags);
5295 /* Adjust other cursors pointing to mp */
5297 unsigned i = mc->mc_top;
5298 MDB_page *mp = mc->mc_pg[i];
5300 for (m2 = mc->mc_txn->mt_cursors[mc->mc_dbi]; m2; m2=m2->mc_next) {
5301 if (m2 == mc || m2->mc_snum < mc->mc_snum) continue;
5302 if (m2->mc_pg[i] == mp && m2->mc_ki[i] == mc->mc_ki[i]) {
5303 mdb_xcursor_init1(m2, leaf);
5307 /* we've done our job */
5310 if (flags & MDB_APPENDDUP)
5311 xflags |= MDB_APPEND;
5312 rc = mdb_cursor_put(&mc->mc_xcursor->mx_cursor, data, &xdata, xflags);
5313 if (flags & F_SUBDATA) {
5314 void *db = NODEDATA(leaf);
5315 memcpy(db, &mc->mc_xcursor->mx_db, sizeof(MDB_db));
5318 /* sub-writes might have failed so check rc again.
5319 * Don't increment count if we just replaced an existing item.
5321 if (!rc && !(flags & MDB_CURRENT))
5322 mc->mc_db->md_entries++;
5323 if (flags & MDB_MULTIPLE) {
5325 if (mcount < data[1].mv_size) {
5326 data[0].mv_data = (char *)data[0].mv_data + data[0].mv_size;
5327 leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
5333 /* If we succeeded and the key didn't exist before, make sure
5334 * the cursor is marked valid.
5337 mc->mc_flags |= C_INITIALIZED;
5342 mdb_cursor_del(MDB_cursor *mc, unsigned int flags)
5347 if (F_ISSET(mc->mc_txn->mt_flags, MDB_TXN_RDONLY))
5350 if (!(mc->mc_flags & C_INITIALIZED))
5353 rc = mdb_cursor_touch(mc);
5357 leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
5359 if (!IS_LEAF2(mc->mc_pg[mc->mc_top]) && F_ISSET(leaf->mn_flags, F_DUPDATA)) {
5360 if (flags != MDB_NODUPDATA) {
5361 if (!F_ISSET(leaf->mn_flags, F_SUBDATA)) {
5362 mc->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(leaf);
5364 rc = mdb_cursor_del(&mc->mc_xcursor->mx_cursor, 0);
5365 /* If sub-DB still has entries, we're done */
5366 if (mc->mc_xcursor->mx_db.md_entries) {
5367 if (leaf->mn_flags & F_SUBDATA) {
5368 /* update subDB info */
5369 void *db = NODEDATA(leaf);
5370 memcpy(db, &mc->mc_xcursor->mx_db, sizeof(MDB_db));
5372 /* shrink fake page */
5373 mdb_node_shrink(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
5375 mc->mc_db->md_entries--;
5378 /* otherwise fall thru and delete the sub-DB */
5381 if (leaf->mn_flags & F_SUBDATA) {
5382 /* add all the child DB's pages to the free list */
5383 rc = mdb_drop0(&mc->mc_xcursor->mx_cursor, 0);
5384 if (rc == MDB_SUCCESS) {
5385 mc->mc_db->md_entries -=
5386 mc->mc_xcursor->mx_db.md_entries;
5391 return mdb_cursor_del0(mc, leaf);
5394 /** Allocate and initialize new pages for a database.
5395 * @param[in] mc a cursor on the database being added to.
5396 * @param[in] flags flags defining what type of page is being allocated.
5397 * @param[in] num the number of pages to allocate. This is usually 1,
5398 * unless allocating overflow pages for a large record.
5399 * @param[out] mp Address of a page, or NULL on failure.
5400 * @return 0 on success, non-zero on failure.
5403 mdb_page_new(MDB_cursor *mc, uint32_t flags, int num, MDB_page **mp)
5408 if ((rc = mdb_page_alloc(mc, num, &np)))
5410 DPRINTF("allocated new mpage %zu, page size %u",
5411 np->mp_pgno, mc->mc_txn->mt_env->me_psize);
5412 np->mp_flags = flags | P_DIRTY;
5413 np->mp_lower = PAGEHDRSZ;
5414 np->mp_upper = mc->mc_txn->mt_env->me_psize;
5417 mc->mc_db->md_branch_pages++;
5418 else if (IS_LEAF(np))
5419 mc->mc_db->md_leaf_pages++;
5420 else if (IS_OVERFLOW(np)) {
5421 mc->mc_db->md_overflow_pages += num;
5429 /** Calculate the size of a leaf node.
5430 * The size depends on the environment's page size; if a data item
5431 * is too large it will be put onto an overflow page and the node
5432 * size will only include the key and not the data. Sizes are always
5433 * rounded up to an even number of bytes, to guarantee 2-byte alignment
5434 * of the #MDB_node headers.
5435 * @param[in] env The environment handle.
5436 * @param[in] key The key for the node.
5437 * @param[in] data The data for the node.
5438 * @return The number of bytes needed to store the node.
5441 mdb_leaf_size(MDB_env *env, MDB_val *key, MDB_val *data)
5445 sz = LEAFSIZE(key, data);
5446 if (sz >= env->me_nodemax) {
5447 /* put on overflow page */
5448 sz -= data->mv_size - sizeof(pgno_t);
5452 return sz + sizeof(indx_t);
5455 /** Calculate the size of a branch node.
5456 * The size should depend on the environment's page size but since
5457 * we currently don't support spilling large keys onto overflow
5458 * pages, it's simply the size of the #MDB_node header plus the
5459 * size of the key. Sizes are always rounded up to an even number
5460 * of bytes, to guarantee 2-byte alignment of the #MDB_node headers.
5461 * @param[in] env The environment handle.
5462 * @param[in] key The key for the node.
5463 * @return The number of bytes needed to store the node.
5466 mdb_branch_size(MDB_env *env, MDB_val *key)
5471 if (sz >= env->me_nodemax) {
5472 /* put on overflow page */
5473 /* not implemented */
5474 /* sz -= key->size - sizeof(pgno_t); */
5477 return sz + sizeof(indx_t);
5480 /** Add a node to the page pointed to by the cursor.
5481 * @param[in] mc The cursor for this operation.
5482 * @param[in] indx The index on the page where the new node should be added.
5483 * @param[in] key The key for the new node.
5484 * @param[in] data The data for the new node, if any.
5485 * @param[in] pgno The page number, if adding a branch node.
5486 * @param[in] flags Flags for the node.
5487 * @return 0 on success, non-zero on failure. Possible errors are:
5489 * <li>ENOMEM - failed to allocate overflow pages for the node.
5490 * <li>MDB_PAGE_FULL - there is insufficient room in the page. This error
5491 * should never happen since all callers already calculate the
5492 * page's free space before calling this function.
5496 mdb_node_add(MDB_cursor *mc, indx_t indx,
5497 MDB_val *key, MDB_val *data, pgno_t pgno, unsigned int flags)
5500 size_t node_size = NODESIZE;
5503 MDB_page *mp = mc->mc_pg[mc->mc_top];
5504 MDB_page *ofp = NULL; /* overflow page */
5507 assert(mp->mp_upper >= mp->mp_lower);
5509 DPRINTF("add to %s %spage %zu index %i, data size %zu key size %zu [%s]",
5510 IS_LEAF(mp) ? "leaf" : "branch",
5511 IS_SUBP(mp) ? "sub-" : "",
5512 mp->mp_pgno, indx, data ? data->mv_size : 0,
5513 key ? key->mv_size : 0, key ? DKEY(key) : NULL);
5516 /* Move higher keys up one slot. */
5517 int ksize = mc->mc_db->md_pad, dif;
5518 char *ptr = LEAF2KEY(mp, indx, ksize);
5519 dif = NUMKEYS(mp) - indx;
5521 memmove(ptr+ksize, ptr, dif*ksize);
5522 /* insert new key */
5523 memcpy(ptr, key->mv_data, ksize);
5525 /* Just using these for counting */
5526 mp->mp_lower += sizeof(indx_t);
5527 mp->mp_upper -= ksize - sizeof(indx_t);
5532 node_size += key->mv_size;
5536 if (F_ISSET(flags, F_BIGDATA)) {
5537 /* Data already on overflow page. */
5538 node_size += sizeof(pgno_t);
5539 } else if (node_size + data->mv_size >= mc->mc_txn->mt_env->me_nodemax) {
5540 int ovpages = OVPAGES(data->mv_size, mc->mc_txn->mt_env->me_psize);
5542 /* Put data on overflow page. */
5543 DPRINTF("data size is %zu, node would be %zu, put data on overflow page",
5544 data->mv_size, node_size+data->mv_size);
5545 node_size += sizeof(pgno_t);
5546 if ((rc = mdb_page_new(mc, P_OVERFLOW, ovpages, &ofp)))
5548 DPRINTF("allocated overflow page %zu", ofp->mp_pgno);
5551 node_size += data->mv_size;
5554 node_size += node_size & 1;
5556 if (node_size + sizeof(indx_t) > SIZELEFT(mp)) {
5557 DPRINTF("not enough room in page %zu, got %u ptrs",
5558 mp->mp_pgno, NUMKEYS(mp));
5559 DPRINTF("upper - lower = %u - %u = %u", mp->mp_upper, mp->mp_lower,
5560 mp->mp_upper - mp->mp_lower);
5561 DPRINTF("node size = %zu", node_size);
5562 return MDB_PAGE_FULL;
5565 /* Move higher pointers up one slot. */
5566 for (i = NUMKEYS(mp); i > indx; i--)
5567 mp->mp_ptrs[i] = mp->mp_ptrs[i - 1];
5569 /* Adjust free space offsets. */
5570 ofs = mp->mp_upper - node_size;
5571 assert(ofs >= mp->mp_lower + sizeof(indx_t));
5572 mp->mp_ptrs[indx] = ofs;
5574 mp->mp_lower += sizeof(indx_t);
5576 /* Write the node data. */
5577 node = NODEPTR(mp, indx);
5578 node->mn_ksize = (key == NULL) ? 0 : key->mv_size;
5579 node->mn_flags = flags;
5581 SETDSZ(node,data->mv_size);
5586 memcpy(NODEKEY(node), key->mv_data, key->mv_size);
5591 if (F_ISSET(flags, F_BIGDATA))
5592 memcpy(node->mn_data + key->mv_size, data->mv_data,
5594 else if (F_ISSET(flags, MDB_RESERVE))
5595 data->mv_data = node->mn_data + key->mv_size;
5597 memcpy(node->mn_data + key->mv_size, data->mv_data,
5600 memcpy(node->mn_data + key->mv_size, &ofp->mp_pgno,
5602 if (F_ISSET(flags, MDB_RESERVE))
5603 data->mv_data = METADATA(ofp);
5605 memcpy(METADATA(ofp), data->mv_data, data->mv_size);
5612 /** Delete the specified node from a page.
5613 * @param[in] mp The page to operate on.
5614 * @param[in] indx The index of the node to delete.
5615 * @param[in] ksize The size of a node. Only used if the page is
5616 * part of a #MDB_DUPFIXED database.
5619 mdb_node_del(MDB_page *mp, indx_t indx, int ksize)
5622 indx_t i, j, numkeys, ptr;
5629 COPY_PGNO(pgno, mp->mp_pgno);
5630 DPRINTF("delete node %u on %s page %zu", indx,
5631 IS_LEAF(mp) ? "leaf" : "branch", pgno);
5634 assert(indx < NUMKEYS(mp));
5637 int x = NUMKEYS(mp) - 1 - indx;
5638 base = LEAF2KEY(mp, indx, ksize);
5640 memmove(base, base + ksize, x * ksize);
5641 mp->mp_lower -= sizeof(indx_t);
5642 mp->mp_upper += ksize - sizeof(indx_t);
5646 node = NODEPTR(mp, indx);
5647 sz = NODESIZE + node->mn_ksize;
5649 if (F_ISSET(node->mn_flags, F_BIGDATA))
5650 sz += sizeof(pgno_t);
5652 sz += NODEDSZ(node);
5656 ptr = mp->mp_ptrs[indx];
5657 numkeys = NUMKEYS(mp);
5658 for (i = j = 0; i < numkeys; i++) {
5660 mp->mp_ptrs[j] = mp->mp_ptrs[i];
5661 if (mp->mp_ptrs[i] < ptr)
5662 mp->mp_ptrs[j] += sz;
5667 base = (char *)mp + mp->mp_upper;
5668 memmove(base + sz, base, ptr - mp->mp_upper);
5670 mp->mp_lower -= sizeof(indx_t);
5674 /** Compact the main page after deleting a node on a subpage.
5675 * @param[in] mp The main page to operate on.
5676 * @param[in] indx The index of the subpage on the main page.
5679 mdb_node_shrink(MDB_page *mp, indx_t indx)
5686 indx_t i, numkeys, ptr;
5688 node = NODEPTR(mp, indx);
5689 sp = (MDB_page *)NODEDATA(node);
5690 osize = NODEDSZ(node);
5692 delta = sp->mp_upper - sp->mp_lower;
5693 SETDSZ(node, osize - delta);
5694 xp = (MDB_page *)((char *)sp + delta);
5696 /* shift subpage upward */
5698 nsize = NUMKEYS(sp) * sp->mp_pad;
5699 memmove(METADATA(xp), METADATA(sp), nsize);
5702 nsize = osize - sp->mp_upper;
5703 numkeys = NUMKEYS(sp);
5704 for (i=numkeys-1; i>=0; i--)
5705 xp->mp_ptrs[i] = sp->mp_ptrs[i] - delta;
5707 xp->mp_upper = sp->mp_lower;
5708 xp->mp_lower = sp->mp_lower;
5709 xp->mp_flags = sp->mp_flags;
5710 xp->mp_pad = sp->mp_pad;
5711 COPY_PGNO(xp->mp_pgno, mp->mp_pgno);
5713 /* shift lower nodes upward */
5714 ptr = mp->mp_ptrs[indx];
5715 numkeys = NUMKEYS(mp);
5716 for (i = 0; i < numkeys; i++) {
5717 if (mp->mp_ptrs[i] <= ptr)
5718 mp->mp_ptrs[i] += delta;
5721 base = (char *)mp + mp->mp_upper;
5722 memmove(base + delta, base, ptr - mp->mp_upper + NODESIZE + NODEKSZ(node));
5723 mp->mp_upper += delta;
5726 /** Initial setup of a sorted-dups cursor.
5727 * Sorted duplicates are implemented as a sub-database for the given key.
5728 * The duplicate data items are actually keys of the sub-database.
5729 * Operations on the duplicate data items are performed using a sub-cursor
5730 * initialized when the sub-database is first accessed. This function does
5731 * the preliminary setup of the sub-cursor, filling in the fields that
5732 * depend only on the parent DB.
5733 * @param[in] mc The main cursor whose sorted-dups cursor is to be initialized.
5736 mdb_xcursor_init0(MDB_cursor *mc)
5738 MDB_xcursor *mx = mc->mc_xcursor;
5740 mx->mx_cursor.mc_xcursor = NULL;
5741 mx->mx_cursor.mc_txn = mc->mc_txn;
5742 mx->mx_cursor.mc_db = &mx->mx_db;
5743 mx->mx_cursor.mc_dbx = &mx->mx_dbx;
5744 mx->mx_cursor.mc_dbi = mc->mc_dbi+1;
5745 mx->mx_cursor.mc_dbflag = &mx->mx_dbflag;
5746 mx->mx_cursor.mc_snum = 0;
5747 mx->mx_cursor.mc_top = 0;
5748 mx->mx_cursor.mc_flags = C_SUB;
5749 mx->mx_dbx.md_cmp = mc->mc_dbx->md_dcmp;
5750 mx->mx_dbx.md_dcmp = NULL;
5751 mx->mx_dbx.md_rel = mc->mc_dbx->md_rel;
5754 /** Final setup of a sorted-dups cursor.
5755 * Sets up the fields that depend on the data from the main cursor.
5756 * @param[in] mc The main cursor whose sorted-dups cursor is to be initialized.
5757 * @param[in] node The data containing the #MDB_db record for the
5758 * sorted-dup database.
5761 mdb_xcursor_init1(MDB_cursor *mc, MDB_node *node)
5763 MDB_xcursor *mx = mc->mc_xcursor;
5765 if (node->mn_flags & F_SUBDATA) {
5766 memcpy(&mx->mx_db, NODEDATA(node), sizeof(MDB_db));
5767 mx->mx_cursor.mc_pg[0] = 0;
5768 mx->mx_cursor.mc_snum = 0;
5769 mx->mx_cursor.mc_flags = C_SUB;
5771 MDB_page *fp = NODEDATA(node);
5772 mx->mx_db.md_pad = mc->mc_pg[mc->mc_top]->mp_pad;
5773 mx->mx_db.md_flags = 0;
5774 mx->mx_db.md_depth = 1;
5775 mx->mx_db.md_branch_pages = 0;
5776 mx->mx_db.md_leaf_pages = 1;
5777 mx->mx_db.md_overflow_pages = 0;
5778 mx->mx_db.md_entries = NUMKEYS(fp);
5779 COPY_PGNO(mx->mx_db.md_root, fp->mp_pgno);
5780 mx->mx_cursor.mc_snum = 1;
5781 mx->mx_cursor.mc_flags = C_INITIALIZED|C_SUB;
5782 mx->mx_cursor.mc_top = 0;
5783 mx->mx_cursor.mc_pg[0] = fp;
5784 mx->mx_cursor.mc_ki[0] = 0;
5785 if (mc->mc_db->md_flags & MDB_DUPFIXED) {
5786 mx->mx_db.md_flags = MDB_DUPFIXED;
5787 mx->mx_db.md_pad = fp->mp_pad;
5788 if (mc->mc_db->md_flags & MDB_INTEGERDUP)
5789 mx->mx_db.md_flags |= MDB_INTEGERKEY;
5792 DPRINTF("Sub-db %u for db %u root page %zu", mx->mx_cursor.mc_dbi, mc->mc_dbi,
5794 mx->mx_dbflag = DB_VALID | (F_ISSET(mc->mc_pg[mc->mc_top]->mp_flags, P_DIRTY) ?
5796 mx->mx_dbx.md_name.mv_data = NODEKEY(node);
5797 mx->mx_dbx.md_name.mv_size = node->mn_ksize;
5798 #if UINT_MAX < SIZE_MAX
5799 if (mx->mx_dbx.md_cmp == mdb_cmp_int && mx->mx_db.md_pad == sizeof(size_t))
5800 #ifdef MISALIGNED_OK
5801 mx->mx_dbx.md_cmp = mdb_cmp_long;
5803 mx->mx_dbx.md_cmp = mdb_cmp_cint;
5808 /** Initialize a cursor for a given transaction and database. */
5810 mdb_cursor_init(MDB_cursor *mc, MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx)
5815 mc->mc_db = &txn->mt_dbs[dbi];
5816 mc->mc_dbx = &txn->mt_dbxs[dbi];
5817 mc->mc_dbflag = &txn->mt_dbflags[dbi];
5822 if (txn->mt_dbs[dbi].md_flags & MDB_DUPSORT) {
5824 mc->mc_xcursor = mx;
5825 mdb_xcursor_init0(mc);
5827 mc->mc_xcursor = NULL;
5829 if (*mc->mc_dbflag & DB_STALE) {
5830 mdb_page_search(mc, NULL, MDB_PS_ROOTONLY);
5835 mdb_cursor_open(MDB_txn *txn, MDB_dbi dbi, MDB_cursor **ret)
5838 MDB_xcursor *mx = NULL;
5839 size_t size = sizeof(MDB_cursor);
5841 if (txn == NULL || ret == NULL || dbi >= txn->mt_numdbs || !(txn->mt_dbflags[dbi] & DB_VALID))
5844 /* Allow read access to the freelist */
5845 if (!dbi && !F_ISSET(txn->mt_flags, MDB_TXN_RDONLY))
5848 if (txn->mt_dbs[dbi].md_flags & MDB_DUPSORT)
5849 size += sizeof(MDB_xcursor);
5851 if ((mc = malloc(size)) != NULL) {
5852 if (txn->mt_dbs[dbi].md_flags & MDB_DUPSORT) {
5853 mx = (MDB_xcursor *)(mc + 1);
5855 mdb_cursor_init(mc, txn, dbi, mx);
5856 if (txn->mt_cursors) {
5857 mc->mc_next = txn->mt_cursors[dbi];
5858 txn->mt_cursors[dbi] = mc;
5859 mc->mc_flags |= C_UNTRACK;
5861 mc->mc_flags |= C_ALLOCD;
5872 mdb_cursor_renew(MDB_txn *txn, MDB_cursor *mc)
5876 if (txn == NULL || mc == NULL || mc->mc_dbi >= txn->mt_numdbs)
5879 if ((mc->mc_flags & C_UNTRACK) || txn->mt_cursors)
5882 flags = mc->mc_flags;
5884 mdb_cursor_init(mc, txn, mc->mc_dbi, mc->mc_xcursor);
5886 mc->mc_flags |= (flags & C_ALLOCD);
5890 /* Return the count of duplicate data items for the current key */
5892 mdb_cursor_count(MDB_cursor *mc, size_t *countp)
5896 if (mc == NULL || countp == NULL)
5899 if (!(mc->mc_db->md_flags & MDB_DUPSORT))
5902 leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
5903 if (!F_ISSET(leaf->mn_flags, F_DUPDATA)) {
5906 if (!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED))
5909 *countp = mc->mc_xcursor->mx_db.md_entries;
5915 mdb_cursor_close(MDB_cursor *mc)
5918 /* remove from txn, if tracked */
5919 if ((mc->mc_flags & C_UNTRACK) && mc->mc_txn->mt_cursors) {
5920 MDB_cursor **prev = &mc->mc_txn->mt_cursors[mc->mc_dbi];
5921 while (*prev && *prev != mc) prev = &(*prev)->mc_next;
5923 *prev = mc->mc_next;
5925 if (mc->mc_flags & C_ALLOCD)
5931 mdb_cursor_txn(MDB_cursor *mc)
5933 if (!mc) return NULL;
5938 mdb_cursor_dbi(MDB_cursor *mc)
5944 /** Replace the key for a node with a new key.
5945 * @param[in] mp The page containing the node to operate on.
5946 * @param[in] indx The index of the node to operate on.
5947 * @param[in] key The new key to use.
5948 * @return 0 on success, non-zero on failure.
5951 mdb_update_key(MDB_cursor *mc, MDB_val *key)
5958 indx_t ptr, i, numkeys, indx;
5961 indx = mc->mc_ki[mc->mc_top];
5962 mp = mc->mc_pg[mc->mc_top];
5963 node = NODEPTR(mp, indx);
5964 ptr = mp->mp_ptrs[indx];
5968 char kbuf2[(MDB_MAXKEYSIZE*2+1)];
5969 k2.mv_data = NODEKEY(node);
5970 k2.mv_size = node->mn_ksize;
5971 DPRINTF("update key %u (ofs %u) [%s] to [%s] on page %zu",
5973 mdb_dkey(&k2, kbuf2),
5979 delta0 = delta = key->mv_size - node->mn_ksize;
5981 /* Must be 2-byte aligned. If new key is
5982 * shorter by 1, the shift will be skipped.
5984 delta += (delta & 1);
5986 if (delta > 0 && SIZELEFT(mp) < delta) {
5988 /* not enough space left, do a delete and split */
5989 DPRINTF("Not enough room, delta = %d, splitting...", delta);
5990 pgno = NODEPGNO(node);
5991 mdb_node_del(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], 0);
5992 return mdb_page_split(mc, key, NULL, pgno, MDB_SPLIT_REPLACE);
5995 numkeys = NUMKEYS(mp);
5996 for (i = 0; i < numkeys; i++) {
5997 if (mp->mp_ptrs[i] <= ptr)
5998 mp->mp_ptrs[i] -= delta;
6001 base = (char *)mp + mp->mp_upper;
6002 len = ptr - mp->mp_upper + NODESIZE;
6003 memmove(base - delta, base, len);
6004 mp->mp_upper -= delta;
6006 node = NODEPTR(mp, indx);
6009 /* But even if no shift was needed, update ksize */
6011 node->mn_ksize = key->mv_size;
6014 memcpy(NODEKEY(node), key->mv_data, key->mv_size);
6020 mdb_cursor_copy(const MDB_cursor *csrc, MDB_cursor *cdst);
6022 /** Move a node from csrc to cdst.
6025 mdb_node_move(MDB_cursor *csrc, MDB_cursor *cdst)
6032 unsigned short flags;
6036 /* Mark src and dst as dirty. */
6037 if ((rc = mdb_page_touch(csrc)) ||
6038 (rc = mdb_page_touch(cdst)))
6041 if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
6042 srcnode = NODEPTR(csrc->mc_pg[csrc->mc_top], 0); /* fake */
6043 key.mv_size = csrc->mc_db->md_pad;
6044 key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], csrc->mc_ki[csrc->mc_top], key.mv_size);
6046 data.mv_data = NULL;
6050 srcnode = NODEPTR(csrc->mc_pg[csrc->mc_top], csrc->mc_ki[csrc->mc_top]);
6051 assert(!((long)srcnode&1));
6052 srcpg = NODEPGNO(srcnode);
6053 flags = srcnode->mn_flags;
6054 if (csrc->mc_ki[csrc->mc_top] == 0 && IS_BRANCH(csrc->mc_pg[csrc->mc_top])) {
6055 unsigned int snum = csrc->mc_snum;
6057 /* must find the lowest key below src */
6058 mdb_page_search_lowest(csrc);
6059 if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
6060 key.mv_size = csrc->mc_db->md_pad;
6061 key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], 0, key.mv_size);
6063 s2 = NODEPTR(csrc->mc_pg[csrc->mc_top], 0);
6064 key.mv_size = NODEKSZ(s2);
6065 key.mv_data = NODEKEY(s2);
6067 csrc->mc_snum = snum--;
6068 csrc->mc_top = snum;
6070 key.mv_size = NODEKSZ(srcnode);
6071 key.mv_data = NODEKEY(srcnode);
6073 data.mv_size = NODEDSZ(srcnode);
6074 data.mv_data = NODEDATA(srcnode);
6076 if (IS_BRANCH(cdst->mc_pg[cdst->mc_top]) && cdst->mc_ki[cdst->mc_top] == 0) {
6077 unsigned int snum = cdst->mc_snum;
6080 /* must find the lowest key below dst */
6081 mdb_page_search_lowest(cdst);
6082 if (IS_LEAF2(cdst->mc_pg[cdst->mc_top])) {
6083 bkey.mv_size = cdst->mc_db->md_pad;
6084 bkey.mv_data = LEAF2KEY(cdst->mc_pg[cdst->mc_top], 0, bkey.mv_size);
6086 s2 = NODEPTR(cdst->mc_pg[cdst->mc_top], 0);
6087 bkey.mv_size = NODEKSZ(s2);
6088 bkey.mv_data = NODEKEY(s2);
6090 cdst->mc_snum = snum--;
6091 cdst->mc_top = snum;
6092 mdb_cursor_copy(cdst, &mn);
6094 rc = mdb_update_key(&mn, &bkey);
6099 DPRINTF("moving %s node %u [%s] on page %zu to node %u on page %zu",
6100 IS_LEAF(csrc->mc_pg[csrc->mc_top]) ? "leaf" : "branch",
6101 csrc->mc_ki[csrc->mc_top],
6103 csrc->mc_pg[csrc->mc_top]->mp_pgno,
6104 cdst->mc_ki[cdst->mc_top], cdst->mc_pg[cdst->mc_top]->mp_pgno);
6106 /* Add the node to the destination page.
6108 rc = mdb_node_add(cdst, cdst->mc_ki[cdst->mc_top], &key, &data, srcpg, flags);
6109 if (rc != MDB_SUCCESS)
6112 /* Delete the node from the source page.
6114 mdb_node_del(csrc->mc_pg[csrc->mc_top], csrc->mc_ki[csrc->mc_top], key.mv_size);
6117 /* Adjust other cursors pointing to mp */
6118 MDB_cursor *m2, *m3;
6119 MDB_dbi dbi = csrc->mc_dbi;
6120 MDB_page *mp = csrc->mc_pg[csrc->mc_top];
6122 if (csrc->mc_flags & C_SUB)
6125 for (m2 = csrc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
6126 if (m2 == csrc) continue;
6127 if (csrc->mc_flags & C_SUB)
6128 m3 = &m2->mc_xcursor->mx_cursor;
6131 if (m3->mc_pg[csrc->mc_top] == mp && m3->mc_ki[csrc->mc_top] ==
6132 csrc->mc_ki[csrc->mc_top]) {
6133 m3->mc_pg[csrc->mc_top] = cdst->mc_pg[cdst->mc_top];
6134 m3->mc_ki[csrc->mc_top] = cdst->mc_ki[cdst->mc_top];
6139 /* Update the parent separators.
6141 if (csrc->mc_ki[csrc->mc_top] == 0) {
6142 if (csrc->mc_ki[csrc->mc_top-1] != 0) {
6143 if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
6144 key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], 0, key.mv_size);
6146 srcnode = NODEPTR(csrc->mc_pg[csrc->mc_top], 0);
6147 key.mv_size = NODEKSZ(srcnode);
6148 key.mv_data = NODEKEY(srcnode);
6150 DPRINTF("update separator for source page %zu to [%s]",
6151 csrc->mc_pg[csrc->mc_top]->mp_pgno, DKEY(&key));
6152 mdb_cursor_copy(csrc, &mn);
6155 if ((rc = mdb_update_key(&mn, &key)) != MDB_SUCCESS)
6158 if (IS_BRANCH(csrc->mc_pg[csrc->mc_top])) {
6160 indx_t ix = csrc->mc_ki[csrc->mc_top];
6161 nullkey.mv_size = 0;
6162 csrc->mc_ki[csrc->mc_top] = 0;
6163 rc = mdb_update_key(csrc, &nullkey);
6164 csrc->mc_ki[csrc->mc_top] = ix;
6165 assert(rc == MDB_SUCCESS);
6169 if (cdst->mc_ki[cdst->mc_top] == 0) {
6170 if (cdst->mc_ki[cdst->mc_top-1] != 0) {
6171 if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
6172 key.mv_data = LEAF2KEY(cdst->mc_pg[cdst->mc_top], 0, key.mv_size);
6174 srcnode = NODEPTR(cdst->mc_pg[cdst->mc_top], 0);
6175 key.mv_size = NODEKSZ(srcnode);
6176 key.mv_data = NODEKEY(srcnode);
6178 DPRINTF("update separator for destination page %zu to [%s]",
6179 cdst->mc_pg[cdst->mc_top]->mp_pgno, DKEY(&key));
6180 mdb_cursor_copy(cdst, &mn);
6183 if ((rc = mdb_update_key(&mn, &key)) != MDB_SUCCESS)
6186 if (IS_BRANCH(cdst->mc_pg[cdst->mc_top])) {
6188 indx_t ix = cdst->mc_ki[cdst->mc_top];
6189 nullkey.mv_size = 0;
6190 cdst->mc_ki[cdst->mc_top] = 0;
6191 rc = mdb_update_key(cdst, &nullkey);
6192 cdst->mc_ki[cdst->mc_top] = ix;
6193 assert(rc == MDB_SUCCESS);
6200 /** Merge one page into another.
6201 * The nodes from the page pointed to by \b csrc will
6202 * be copied to the page pointed to by \b cdst and then
6203 * the \b csrc page will be freed.
6204 * @param[in] csrc Cursor pointing to the source page.
6205 * @param[in] cdst Cursor pointing to the destination page.
6208 mdb_page_merge(MDB_cursor *csrc, MDB_cursor *cdst)
6216 DPRINTF("merging page %zu into %zu", csrc->mc_pg[csrc->mc_top]->mp_pgno,
6217 cdst->mc_pg[cdst->mc_top]->mp_pgno);
6219 assert(csrc->mc_snum > 1); /* can't merge root page */
6220 assert(cdst->mc_snum > 1);
6222 /* Mark dst as dirty. */
6223 if ((rc = mdb_page_touch(cdst)))
6226 /* Move all nodes from src to dst.
6228 j = nkeys = NUMKEYS(cdst->mc_pg[cdst->mc_top]);
6229 if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
6230 key.mv_size = csrc->mc_db->md_pad;
6231 key.mv_data = METADATA(csrc->mc_pg[csrc->mc_top]);
6232 for (i = 0; i < NUMKEYS(csrc->mc_pg[csrc->mc_top]); i++, j++) {
6233 rc = mdb_node_add(cdst, j, &key, NULL, 0, 0);
6234 if (rc != MDB_SUCCESS)
6236 key.mv_data = (char *)key.mv_data + key.mv_size;
6239 for (i = 0; i < NUMKEYS(csrc->mc_pg[csrc->mc_top]); i++, j++) {
6240 srcnode = NODEPTR(csrc->mc_pg[csrc->mc_top], i);
6241 if (i == 0 && IS_BRANCH(csrc->mc_pg[csrc->mc_top])) {
6242 unsigned int snum = csrc->mc_snum;
6244 /* must find the lowest key below src */
6245 mdb_page_search_lowest(csrc);
6246 if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
6247 key.mv_size = csrc->mc_db->md_pad;
6248 key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], 0, key.mv_size);
6250 s2 = NODEPTR(csrc->mc_pg[csrc->mc_top], 0);
6251 key.mv_size = NODEKSZ(s2);
6252 key.mv_data = NODEKEY(s2);
6254 csrc->mc_snum = snum--;
6255 csrc->mc_top = snum;
6257 key.mv_size = srcnode->mn_ksize;
6258 key.mv_data = NODEKEY(srcnode);
6261 data.mv_size = NODEDSZ(srcnode);
6262 data.mv_data = NODEDATA(srcnode);
6263 rc = mdb_node_add(cdst, j, &key, &data, NODEPGNO(srcnode), srcnode->mn_flags);
6264 if (rc != MDB_SUCCESS)
6269 DPRINTF("dst page %zu now has %u keys (%.1f%% filled)",
6270 cdst->mc_pg[cdst->mc_top]->mp_pgno, NUMKEYS(cdst->mc_pg[cdst->mc_top]), (float)PAGEFILL(cdst->mc_txn->mt_env, cdst->mc_pg[cdst->mc_top]) / 10);
6272 /* Unlink the src page from parent and add to free list.
6274 mdb_node_del(csrc->mc_pg[csrc->mc_top-1], csrc->mc_ki[csrc->mc_top-1], 0);
6275 if (csrc->mc_ki[csrc->mc_top-1] == 0) {
6278 rc = mdb_update_key(csrc, &key);
6284 mdb_midl_append(&csrc->mc_txn->mt_free_pgs, csrc->mc_pg[csrc->mc_top]->mp_pgno);
6285 if (IS_LEAF(csrc->mc_pg[csrc->mc_top]))
6286 csrc->mc_db->md_leaf_pages--;
6288 csrc->mc_db->md_branch_pages--;
6290 /* Adjust other cursors pointing to mp */
6291 MDB_cursor *m2, *m3;
6292 MDB_dbi dbi = csrc->mc_dbi;
6293 MDB_page *mp = cdst->mc_pg[cdst->mc_top];
6295 if (csrc->mc_flags & C_SUB)
6298 for (m2 = csrc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
6299 if (csrc->mc_flags & C_SUB)
6300 m3 = &m2->mc_xcursor->mx_cursor;
6303 if (m3 == csrc) continue;
6304 if (m3->mc_snum < csrc->mc_snum) continue;
6305 if (m3->mc_pg[csrc->mc_top] == csrc->mc_pg[csrc->mc_top]) {
6306 m3->mc_pg[csrc->mc_top] = mp;
6307 m3->mc_ki[csrc->mc_top] += nkeys;
6311 mdb_cursor_pop(csrc);
6313 return mdb_rebalance(csrc);
6316 /** Copy the contents of a cursor.
6317 * @param[in] csrc The cursor to copy from.
6318 * @param[out] cdst The cursor to copy to.
6321 mdb_cursor_copy(const MDB_cursor *csrc, MDB_cursor *cdst)
6325 cdst->mc_txn = csrc->mc_txn;
6326 cdst->mc_dbi = csrc->mc_dbi;
6327 cdst->mc_db = csrc->mc_db;
6328 cdst->mc_dbx = csrc->mc_dbx;
6329 cdst->mc_snum = csrc->mc_snum;
6330 cdst->mc_top = csrc->mc_top;
6331 cdst->mc_flags = csrc->mc_flags;
6333 for (i=0; i<csrc->mc_snum; i++) {
6334 cdst->mc_pg[i] = csrc->mc_pg[i];
6335 cdst->mc_ki[i] = csrc->mc_ki[i];
6339 /** Rebalance the tree after a delete operation.
6340 * @param[in] mc Cursor pointing to the page where rebalancing
6342 * @return 0 on success, non-zero on failure.
6345 mdb_rebalance(MDB_cursor *mc)
6349 unsigned int ptop, minkeys;
6352 minkeys = 1 + (IS_BRANCH(mc->mc_pg[mc->mc_top]));
6356 COPY_PGNO(pgno, mc->mc_pg[mc->mc_top]->mp_pgno);
6357 DPRINTF("rebalancing %s page %zu (has %u keys, %.1f%% full)",
6358 IS_LEAF(mc->mc_pg[mc->mc_top]) ? "leaf" : "branch",
6359 pgno, NUMKEYS(mc->mc_pg[mc->mc_top]), (float)PAGEFILL(mc->mc_txn->mt_env, mc->mc_pg[mc->mc_top]) / 10);
6363 if (PAGEFILL(mc->mc_txn->mt_env, mc->mc_pg[mc->mc_top]) >= FILL_THRESHOLD &&
6364 NUMKEYS(mc->mc_pg[mc->mc_top]) >= minkeys) {
6367 COPY_PGNO(pgno, mc->mc_pg[mc->mc_top]->mp_pgno);
6368 DPRINTF("no need to rebalance page %zu, above fill threshold",
6374 if (mc->mc_snum < 2) {
6375 MDB_page *mp = mc->mc_pg[0];
6377 DPUTS("Can't rebalance a subpage, ignoring");
6380 if (NUMKEYS(mp) == 0) {
6381 DPUTS("tree is completely empty");
6382 mc->mc_db->md_root = P_INVALID;
6383 mc->mc_db->md_depth = 0;
6384 mc->mc_db->md_leaf_pages = 0;
6385 mdb_midl_append(&mc->mc_txn->mt_free_pgs, mp->mp_pgno);
6389 /* Adjust other cursors pointing to mp */
6390 MDB_cursor *m2, *m3;
6391 MDB_dbi dbi = mc->mc_dbi;
6393 if (mc->mc_flags & C_SUB)
6396 for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
6397 if (m2 == mc) continue;
6398 if (mc->mc_flags & C_SUB)
6399 m3 = &m2->mc_xcursor->mx_cursor;
6402 if (m3->mc_snum < mc->mc_snum) continue;
6403 if (m3->mc_pg[0] == mp) {
6409 } else if (IS_BRANCH(mp) && NUMKEYS(mp) == 1) {
6410 DPUTS("collapsing root page!");
6411 mdb_midl_append(&mc->mc_txn->mt_free_pgs, mp->mp_pgno);
6412 mc->mc_db->md_root = NODEPGNO(NODEPTR(mp, 0));
6413 if ((rc = mdb_page_get(mc->mc_txn, mc->mc_db->md_root,
6416 mc->mc_db->md_depth--;
6417 mc->mc_db->md_branch_pages--;
6419 /* Adjust other cursors pointing to mp */
6420 MDB_cursor *m2, *m3;
6421 MDB_dbi dbi = mc->mc_dbi;
6423 if (mc->mc_flags & C_SUB)
6426 for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
6427 if (m2 == mc) continue;
6428 if (mc->mc_flags & C_SUB)
6429 m3 = &m2->mc_xcursor->mx_cursor;
6432 if (m3->mc_snum < mc->mc_snum) continue;
6433 if (m3->mc_pg[0] == mp) {
6434 m3->mc_pg[0] = mc->mc_pg[0];
6441 DPUTS("root page doesn't need rebalancing");
6445 /* The parent (branch page) must have at least 2 pointers,
6446 * otherwise the tree is invalid.
6448 ptop = mc->mc_top-1;
6449 assert(NUMKEYS(mc->mc_pg[ptop]) > 1);
6451 /* Leaf page fill factor is below the threshold.
6452 * Try to move keys from left or right neighbor, or
6453 * merge with a neighbor page.
6458 mdb_cursor_copy(mc, &mn);
6459 mn.mc_xcursor = NULL;
6461 if (mc->mc_ki[ptop] == 0) {
6462 /* We're the leftmost leaf in our parent.
6464 DPUTS("reading right neighbor");
6466 node = NODEPTR(mc->mc_pg[ptop], mn.mc_ki[ptop]);
6467 if ((rc = mdb_page_get(mc->mc_txn, NODEPGNO(node), &mn.mc_pg[mn.mc_top])))
6469 mn.mc_ki[mn.mc_top] = 0;
6470 mc->mc_ki[mc->mc_top] = NUMKEYS(mc->mc_pg[mc->mc_top]);
6472 /* There is at least one neighbor to the left.
6474 DPUTS("reading left neighbor");
6476 node = NODEPTR(mc->mc_pg[ptop], mn.mc_ki[ptop]);
6477 if ((rc = mdb_page_get(mc->mc_txn, NODEPGNO(node), &mn.mc_pg[mn.mc_top])))
6479 mn.mc_ki[mn.mc_top] = NUMKEYS(mn.mc_pg[mn.mc_top]) - 1;
6480 mc->mc_ki[mc->mc_top] = 0;
6483 DPRINTF("found neighbor page %zu (%u keys, %.1f%% full)",
6484 mn.mc_pg[mn.mc_top]->mp_pgno, NUMKEYS(mn.mc_pg[mn.mc_top]), (float)PAGEFILL(mc->mc_txn->mt_env, mn.mc_pg[mn.mc_top]) / 10);
6486 /* If the neighbor page is above threshold and has enough keys,
6487 * move one key from it. Otherwise we should try to merge them.
6488 * (A branch page must never have less than 2 keys.)
6490 minkeys = 1 + (IS_BRANCH(mn.mc_pg[mn.mc_top]));
6491 if (PAGEFILL(mc->mc_txn->mt_env, mn.mc_pg[mn.mc_top]) >= FILL_THRESHOLD && NUMKEYS(mn.mc_pg[mn.mc_top]) > minkeys)
6492 return mdb_node_move(&mn, mc);
6494 if (mc->mc_ki[ptop] == 0)
6495 rc = mdb_page_merge(&mn, mc);
6497 rc = mdb_page_merge(mc, &mn);
6498 mc->mc_flags &= ~C_INITIALIZED;
6503 /** Complete a delete operation started by #mdb_cursor_del(). */
6505 mdb_cursor_del0(MDB_cursor *mc, MDB_node *leaf)
6509 /* add overflow pages to free list */
6510 if (!IS_LEAF2(mc->mc_pg[mc->mc_top]) && F_ISSET(leaf->mn_flags, F_BIGDATA)) {
6514 memcpy(&pg, NODEDATA(leaf), sizeof(pg));
6515 ovpages = OVPAGES(NODEDSZ(leaf), mc->mc_txn->mt_env->me_psize);
6516 mc->mc_db->md_overflow_pages -= ovpages;
6517 for (i=0; i<ovpages; i++) {
6518 DPRINTF("freed ov page %zu", pg);
6519 mdb_midl_append(&mc->mc_txn->mt_free_pgs, pg);
6523 mdb_node_del(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], mc->mc_db->md_pad);
6524 mc->mc_db->md_entries--;
6525 rc = mdb_rebalance(mc);
6526 if (rc != MDB_SUCCESS)
6527 mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
6528 /* if mc points past last node in page, invalidate */
6529 else if (mc->mc_ki[mc->mc_top] >= NUMKEYS(mc->mc_pg[mc->mc_top]))
6530 mc->mc_flags &= ~C_INITIALIZED;
6536 mdb_del(MDB_txn *txn, MDB_dbi dbi,
6537 MDB_val *key, MDB_val *data)
6542 MDB_val rdata, *xdata;
6546 assert(key != NULL);
6548 DPRINTF("====> delete db %u key [%s]", dbi, DKEY(key));
6550 if (txn == NULL || !dbi || dbi >= txn->mt_numdbs || !(txn->mt_dbflags[dbi] & DB_VALID))
6553 if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
6557 if (key->mv_size == 0 || key->mv_size > MDB_MAXKEYSIZE) {
6561 mdb_cursor_init(&mc, txn, dbi, &mx);
6572 rc = mdb_cursor_set(&mc, key, xdata, op, &exact);
6574 /* let mdb_page_split know about this cursor if needed:
6575 * delete will trigger a rebalance; if it needs to move
6576 * a node from one page to another, it will have to
6577 * update the parent's separator key(s). If the new sepkey
6578 * is larger than the current one, the parent page may
6579 * run out of space, triggering a split. We need this
6580 * cursor to be consistent until the end of the rebalance.
6582 mc.mc_next = txn->mt_cursors[dbi];
6583 txn->mt_cursors[dbi] = &mc;
6584 rc = mdb_cursor_del(&mc, data ? 0 : MDB_NODUPDATA);
6585 txn->mt_cursors[dbi] = mc.mc_next;
6590 /** Split a page and insert a new node.
6591 * @param[in,out] mc Cursor pointing to the page and desired insertion index.
6592 * The cursor will be updated to point to the actual page and index where
6593 * the node got inserted after the split.
6594 * @param[in] newkey The key for the newly inserted node.
6595 * @param[in] newdata The data for the newly inserted node.
6596 * @param[in] newpgno The page number, if the new node is a branch node.
6597 * @param[in] nflags The #NODE_ADD_FLAGS for the new node.
6598 * @return 0 on success, non-zero on failure.
6601 mdb_page_split(MDB_cursor *mc, MDB_val *newkey, MDB_val *newdata, pgno_t newpgno,
6602 unsigned int nflags)
6605 int rc = MDB_SUCCESS, ins_new = 0, new_root = 0, newpos = 1, did_split = 0;
6608 unsigned int i, j, split_indx, nkeys, pmax;
6610 MDB_val sepkey, rkey, xdata, *rdata = &xdata;
6612 MDB_page *mp, *rp, *pp;
6617 mp = mc->mc_pg[mc->mc_top];
6618 newindx = mc->mc_ki[mc->mc_top];
6620 DPRINTF("-----> splitting %s page %zu and adding [%s] at index %i",
6621 IS_LEAF(mp) ? "leaf" : "branch", mp->mp_pgno,
6622 DKEY(newkey), mc->mc_ki[mc->mc_top]);
6624 /* Create a right sibling. */
6625 if ((rc = mdb_page_new(mc, mp->mp_flags, 1, &rp)))
6627 DPRINTF("new right sibling: page %zu", rp->mp_pgno);
6629 if (mc->mc_snum < 2) {
6630 if ((rc = mdb_page_new(mc, P_BRANCH, 1, &pp)))
6632 /* shift current top to make room for new parent */
6633 mc->mc_pg[1] = mc->mc_pg[0];
6634 mc->mc_ki[1] = mc->mc_ki[0];
6637 mc->mc_db->md_root = pp->mp_pgno;
6638 DPRINTF("root split! new root = %zu", pp->mp_pgno);
6639 mc->mc_db->md_depth++;
6642 /* Add left (implicit) pointer. */
6643 if ((rc = mdb_node_add(mc, 0, NULL, NULL, mp->mp_pgno, 0)) != MDB_SUCCESS) {
6644 /* undo the pre-push */
6645 mc->mc_pg[0] = mc->mc_pg[1];
6646 mc->mc_ki[0] = mc->mc_ki[1];
6647 mc->mc_db->md_root = mp->mp_pgno;
6648 mc->mc_db->md_depth--;
6655 ptop = mc->mc_top-1;
6656 DPRINTF("parent branch page is %zu", mc->mc_pg[ptop]->mp_pgno);
6659 mc->mc_flags |= C_SPLITTING;
6660 mdb_cursor_copy(mc, &mn);
6661 mn.mc_pg[mn.mc_top] = rp;
6662 mn.mc_ki[ptop] = mc->mc_ki[ptop]+1;
6664 if (nflags & MDB_APPEND) {
6665 mn.mc_ki[mn.mc_top] = 0;
6667 split_indx = newindx;
6672 nkeys = NUMKEYS(mp);
6673 split_indx = nkeys / 2;
6674 if (newindx < split_indx)
6680 unsigned int lsize, rsize, ksize;
6681 /* Move half of the keys to the right sibling */
6683 x = mc->mc_ki[mc->mc_top] - split_indx;
6684 ksize = mc->mc_db->md_pad;
6685 split = LEAF2KEY(mp, split_indx, ksize);
6686 rsize = (nkeys - split_indx) * ksize;
6687 lsize = (nkeys - split_indx) * sizeof(indx_t);
6688 mp->mp_lower -= lsize;
6689 rp->mp_lower += lsize;
6690 mp->mp_upper += rsize - lsize;
6691 rp->mp_upper -= rsize - lsize;
6692 sepkey.mv_size = ksize;
6693 if (newindx == split_indx) {
6694 sepkey.mv_data = newkey->mv_data;
6696 sepkey.mv_data = split;
6699 ins = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], ksize);
6700 memcpy(rp->mp_ptrs, split, rsize);
6701 sepkey.mv_data = rp->mp_ptrs;
6702 memmove(ins+ksize, ins, (split_indx - mc->mc_ki[mc->mc_top]) * ksize);
6703 memcpy(ins, newkey->mv_data, ksize);
6704 mp->mp_lower += sizeof(indx_t);
6705 mp->mp_upper -= ksize - sizeof(indx_t);
6708 memcpy(rp->mp_ptrs, split, x * ksize);
6709 ins = LEAF2KEY(rp, x, ksize);
6710 memcpy(ins, newkey->mv_data, ksize);
6711 memcpy(ins+ksize, split + x * ksize, rsize - x * ksize);
6712 rp->mp_lower += sizeof(indx_t);
6713 rp->mp_upper -= ksize - sizeof(indx_t);
6714 mc->mc_ki[mc->mc_top] = x;
6715 mc->mc_pg[mc->mc_top] = rp;
6720 /* For leaf pages, check the split point based on what
6721 * fits where, since otherwise mdb_node_add can fail.
6723 * This check is only needed when the data items are
6724 * relatively large, such that being off by one will
6725 * make the difference between success or failure.
6727 * It's also relevant if a page happens to be laid out
6728 * such that one half of its nodes are all "small" and
6729 * the other half of its nodes are "large." If the new
6730 * item is also "large" and falls on the half with
6731 * "large" nodes, it also may not fit.
6734 unsigned int psize, nsize;
6735 /* Maximum free space in an empty page */
6736 pmax = mc->mc_txn->mt_env->me_psize - PAGEHDRSZ;
6737 nsize = mdb_leaf_size(mc->mc_txn->mt_env, newkey, newdata);
6738 if ((nkeys < 20) || (nsize > pmax/16)) {
6739 if (newindx <= split_indx) {
6742 for (i=0; i<split_indx; i++) {
6743 node = NODEPTR(mp, i);
6744 psize += NODESIZE + NODEKSZ(node) + sizeof(indx_t);
6745 if (F_ISSET(node->mn_flags, F_BIGDATA))
6746 psize += sizeof(pgno_t);
6748 psize += NODEDSZ(node);
6752 split_indx = newindx;
6763 for (i=nkeys-1; i>=split_indx; i--) {
6764 node = NODEPTR(mp, i);
6765 psize += NODESIZE + NODEKSZ(node) + sizeof(indx_t);
6766 if (F_ISSET(node->mn_flags, F_BIGDATA))
6767 psize += sizeof(pgno_t);
6769 psize += NODEDSZ(node);
6773 split_indx = newindx;
6784 /* First find the separating key between the split pages.
6785 * The case where newindx == split_indx is ambiguous; the
6786 * new item could go to the new page or stay on the original
6787 * page. If newpos == 1 it goes to the new page.
6789 if (newindx == split_indx && newpos) {
6790 sepkey.mv_size = newkey->mv_size;
6791 sepkey.mv_data = newkey->mv_data;
6793 node = NODEPTR(mp, split_indx);
6794 sepkey.mv_size = node->mn_ksize;
6795 sepkey.mv_data = NODEKEY(node);
6799 DPRINTF("separator is [%s]", DKEY(&sepkey));
6801 /* Copy separator key to the parent.
6803 if (SIZELEFT(mn.mc_pg[ptop]) < mdb_branch_size(mc->mc_txn->mt_env, &sepkey)) {
6807 rc = mdb_page_split(&mn, &sepkey, NULL, rp->mp_pgno, 0);
6810 if (mn.mc_snum == mc->mc_snum) {
6811 mc->mc_pg[mc->mc_snum] = mc->mc_pg[mc->mc_top];
6812 mc->mc_ki[mc->mc_snum] = mc->mc_ki[mc->mc_top];
6813 mc->mc_pg[mc->mc_top] = mc->mc_pg[ptop];
6814 mc->mc_ki[mc->mc_top] = mc->mc_ki[ptop];
6819 /* Right page might now have changed parent.
6820 * Check if left page also changed parent.
6822 if (mn.mc_pg[ptop] != mc->mc_pg[ptop] &&
6823 mc->mc_ki[ptop] >= NUMKEYS(mc->mc_pg[ptop])) {
6824 for (i=0; i<ptop; i++) {
6825 mc->mc_pg[i] = mn.mc_pg[i];
6826 mc->mc_ki[i] = mn.mc_ki[i];
6828 mc->mc_pg[ptop] = mn.mc_pg[ptop];
6829 mc->mc_ki[ptop] = mn.mc_ki[ptop] - 1;
6833 rc = mdb_node_add(&mn, mn.mc_ki[ptop], &sepkey, NULL, rp->mp_pgno, 0);
6836 mc->mc_flags ^= C_SPLITTING;
6837 if (rc != MDB_SUCCESS) {
6840 if (nflags & MDB_APPEND) {
6841 mc->mc_pg[mc->mc_top] = rp;
6842 mc->mc_ki[mc->mc_top] = 0;
6843 rc = mdb_node_add(mc, 0, newkey, newdata, newpgno, nflags);
6846 for (i=0; i<mc->mc_top; i++)
6847 mc->mc_ki[i] = mn.mc_ki[i];
6854 /* Move half of the keys to the right sibling. */
6856 /* grab a page to hold a temporary copy */
6857 copy = mdb_page_malloc(mc);
6861 copy->mp_pgno = mp->mp_pgno;
6862 copy->mp_flags = mp->mp_flags;
6863 copy->mp_lower = PAGEHDRSZ;
6864 copy->mp_upper = mc->mc_txn->mt_env->me_psize;
6865 mc->mc_pg[mc->mc_top] = copy;
6866 for (i = j = 0; i <= nkeys; j++) {
6867 if (i == split_indx) {
6868 /* Insert in right sibling. */
6869 /* Reset insert index for right sibling. */
6870 if (i != newindx || (newpos ^ ins_new)) {
6872 mc->mc_pg[mc->mc_top] = rp;
6876 if (i == newindx && !ins_new) {
6877 /* Insert the original entry that caused the split. */
6878 rkey.mv_data = newkey->mv_data;
6879 rkey.mv_size = newkey->mv_size;
6888 /* Update index for the new key. */
6889 mc->mc_ki[mc->mc_top] = j;
6890 } else if (i == nkeys) {
6893 node = NODEPTR(mp, i);
6894 rkey.mv_data = NODEKEY(node);
6895 rkey.mv_size = node->mn_ksize;
6897 xdata.mv_data = NODEDATA(node);
6898 xdata.mv_size = NODEDSZ(node);
6901 pgno = NODEPGNO(node);
6902 flags = node->mn_flags;
6907 if (!IS_LEAF(mp) && j == 0) {
6908 /* First branch index doesn't need key data. */
6912 rc = mdb_node_add(mc, j, &rkey, rdata, pgno, flags);
6916 nkeys = NUMKEYS(copy);
6917 for (i=0; i<nkeys; i++)
6918 mp->mp_ptrs[i] = copy->mp_ptrs[i];
6919 mp->mp_lower = copy->mp_lower;
6920 mp->mp_upper = copy->mp_upper;
6921 memcpy(NODEPTR(mp, nkeys-1), NODEPTR(copy, nkeys-1),
6922 mc->mc_txn->mt_env->me_psize - copy->mp_upper);
6924 /* reset back to original page */
6925 if (newindx < split_indx || (!newpos && newindx == split_indx)) {
6926 mc->mc_pg[mc->mc_top] = mp;
6927 if (nflags & MDB_RESERVE) {
6928 node = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
6929 if (!(node->mn_flags & F_BIGDATA))
6930 newdata->mv_data = NODEDATA(node);
6936 /* return tmp page to freelist */
6937 mdb_page_free(mc->mc_txn->mt_env, copy);
6940 /* Adjust other cursors pointing to mp */
6941 MDB_cursor *m2, *m3;
6942 MDB_dbi dbi = mc->mc_dbi;
6943 int fixup = NUMKEYS(mp);
6945 if (mc->mc_flags & C_SUB)
6948 for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
6949 if (m2 == mc) continue;
6950 if (mc->mc_flags & C_SUB)
6951 m3 = &m2->mc_xcursor->mx_cursor;
6954 if (!(m3->mc_flags & C_INITIALIZED))
6956 if (m3->mc_flags & C_SPLITTING)
6961 for (k=m3->mc_top; k>=0; k--) {
6962 m3->mc_ki[k+1] = m3->mc_ki[k];
6963 m3->mc_pg[k+1] = m3->mc_pg[k];
6965 if (m3->mc_ki[0] >= split_indx) {
6970 m3->mc_pg[0] = mc->mc_pg[0];
6974 if (m3->mc_pg[mc->mc_top] == mp) {
6975 if (m3->mc_ki[mc->mc_top] >= newindx && !(nflags & MDB_SPLIT_REPLACE))
6976 m3->mc_ki[mc->mc_top]++;
6977 if (m3->mc_ki[mc->mc_top] >= fixup) {
6978 m3->mc_pg[mc->mc_top] = rp;
6979 m3->mc_ki[mc->mc_top] -= fixup;
6980 m3->mc_ki[ptop] = mn.mc_ki[ptop];
6982 } else if (!did_split && m3->mc_pg[ptop] == mc->mc_pg[ptop] &&
6983 m3->mc_ki[ptop] >= mc->mc_ki[ptop]) {
6992 mdb_put(MDB_txn *txn, MDB_dbi dbi,
6993 MDB_val *key, MDB_val *data, unsigned int flags)
6998 assert(key != NULL);
6999 assert(data != NULL);
7001 if (txn == NULL || !dbi || dbi >= txn->mt_numdbs || !(txn->mt_dbflags[dbi] & DB_VALID))
7004 if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
7008 if (key->mv_size == 0 || key->mv_size > MDB_MAXKEYSIZE) {
7012 if ((flags & (MDB_NOOVERWRITE|MDB_NODUPDATA|MDB_RESERVE|MDB_APPEND|MDB_APPENDDUP)) != flags)
7015 mdb_cursor_init(&mc, txn, dbi, &mx);
7016 return mdb_cursor_put(&mc, key, data, flags);
7020 mdb_env_set_flags(MDB_env *env, unsigned int flag, int onoff)
7022 if ((flag & CHANGEABLE) != flag)
7025 env->me_flags |= flag;
7027 env->me_flags &= ~flag;
7032 mdb_env_get_flags(MDB_env *env, unsigned int *arg)
7037 *arg = env->me_flags;
7042 mdb_env_get_path(MDB_env *env, const char **arg)
7047 *arg = env->me_path;
7051 /** Common code for #mdb_stat() and #mdb_env_stat().
7052 * @param[in] env the environment to operate in.
7053 * @param[in] db the #MDB_db record containing the stats to return.
7054 * @param[out] arg the address of an #MDB_stat structure to receive the stats.
7055 * @return 0, this function always succeeds.
7058 mdb_stat0(MDB_env *env, MDB_db *db, MDB_stat *arg)
7060 arg->ms_psize = env->me_psize;
7061 arg->ms_depth = db->md_depth;
7062 arg->ms_branch_pages = db->md_branch_pages;
7063 arg->ms_leaf_pages = db->md_leaf_pages;
7064 arg->ms_overflow_pages = db->md_overflow_pages;
7065 arg->ms_entries = db->md_entries;
7070 mdb_env_stat(MDB_env *env, MDB_stat *arg)
7074 if (env == NULL || arg == NULL)
7077 toggle = mdb_env_pick_meta(env);
7079 return mdb_stat0(env, &env->me_metas[toggle]->mm_dbs[MAIN_DBI], arg);
7083 mdb_env_info(MDB_env *env, MDB_envinfo *arg)
7087 if (env == NULL || arg == NULL)
7090 toggle = mdb_env_pick_meta(env);
7091 arg->me_mapaddr = (env->me_flags & MDB_FIXEDMAP) ? env->me_map : 0;
7092 arg->me_mapsize = env->me_mapsize;
7093 arg->me_maxreaders = env->me_maxreaders;
7094 arg->me_numreaders = env->me_numreaders;
7095 arg->me_last_pgno = env->me_metas[toggle]->mm_last_pg;
7096 arg->me_last_txnid = env->me_metas[toggle]->mm_txnid;
7100 /** Set the default comparison functions for a database.
7101 * Called immediately after a database is opened to set the defaults.
7102 * The user can then override them with #mdb_set_compare() or
7103 * #mdb_set_dupsort().
7104 * @param[in] txn A transaction handle returned by #mdb_txn_begin()
7105 * @param[in] dbi A database handle returned by #mdb_dbi_open()
7108 mdb_default_cmp(MDB_txn *txn, MDB_dbi dbi)
7110 uint16_t f = txn->mt_dbs[dbi].md_flags;
7112 txn->mt_dbxs[dbi].md_cmp =
7113 (f & MDB_REVERSEKEY) ? mdb_cmp_memnr :
7114 (f & MDB_INTEGERKEY) ? mdb_cmp_cint : mdb_cmp_memn;
7116 txn->mt_dbxs[dbi].md_dcmp =
7117 !(f & MDB_DUPSORT) ? 0 :
7118 ((f & MDB_INTEGERDUP)
7119 ? ((f & MDB_DUPFIXED) ? mdb_cmp_int : mdb_cmp_cint)
7120 : ((f & MDB_REVERSEDUP) ? mdb_cmp_memnr : mdb_cmp_memn));
7123 int mdb_dbi_open(MDB_txn *txn, const char *name, unsigned int flags, MDB_dbi *dbi)
7128 int rc, dbflag, exact;
7129 unsigned int unused = 0;
7132 if (txn->mt_dbxs[FREE_DBI].md_cmp == NULL) {
7133 mdb_default_cmp(txn, FREE_DBI);
7136 if ((flags & VALID_FLAGS) != flags)
7142 if (flags & PERSISTENT_FLAGS) {
7143 uint16_t f2 = flags & PERSISTENT_FLAGS;
7144 /* make sure flag changes get committed */
7145 if ((txn->mt_dbs[MAIN_DBI].md_flags | f2) != txn->mt_dbs[MAIN_DBI].md_flags) {
7146 txn->mt_dbs[MAIN_DBI].md_flags |= f2;
7147 txn->mt_flags |= MDB_TXN_DIRTY;
7150 mdb_default_cmp(txn, MAIN_DBI);
7154 if (txn->mt_dbxs[MAIN_DBI].md_cmp == NULL) {
7155 mdb_default_cmp(txn, MAIN_DBI);
7158 /* Is the DB already open? */
7160 for (i=2; i<txn->mt_numdbs; i++) {
7161 if (!txn->mt_dbxs[i].md_name.mv_size) {
7162 /* Remember this free slot */
7163 if (!unused) unused = i;
7166 if (len == txn->mt_dbxs[i].md_name.mv_size &&
7167 !strncmp(name, txn->mt_dbxs[i].md_name.mv_data, len)) {
7173 /* If no free slot and max hit, fail */
7174 if (!unused && txn->mt_numdbs >= txn->mt_env->me_maxdbs)
7175 return MDB_DBS_FULL;
7177 /* Find the DB info */
7178 dbflag = DB_NEW|DB_VALID;
7181 key.mv_data = (void *)name;
7182 mdb_cursor_init(&mc, txn, MAIN_DBI, NULL);
7183 rc = mdb_cursor_set(&mc, &key, &data, MDB_SET, &exact);
7184 if (rc == MDB_SUCCESS) {
7185 /* make sure this is actually a DB */
7186 MDB_node *node = NODEPTR(mc.mc_pg[mc.mc_top], mc.mc_ki[mc.mc_top]);
7187 if (!(node->mn_flags & F_SUBDATA))
7189 } else if (rc == MDB_NOTFOUND && (flags & MDB_CREATE)) {
7190 /* Create if requested */
7192 data.mv_size = sizeof(MDB_db);
7193 data.mv_data = &dummy;
7194 memset(&dummy, 0, sizeof(dummy));
7195 dummy.md_root = P_INVALID;
7196 dummy.md_flags = flags & PERSISTENT_FLAGS;
7197 rc = mdb_cursor_put(&mc, &key, &data, F_SUBDATA);
7201 /* OK, got info, add to table */
7202 if (rc == MDB_SUCCESS) {
7203 unsigned int slot = unused ? unused : txn->mt_numdbs;
7204 txn->mt_dbxs[slot].md_name.mv_data = strdup(name);
7205 txn->mt_dbxs[slot].md_name.mv_size = len;
7206 txn->mt_dbxs[slot].md_rel = NULL;
7207 txn->mt_dbflags[slot] = dbflag;
7208 memcpy(&txn->mt_dbs[slot], data.mv_data, sizeof(MDB_db));
7210 txn->mt_env->me_dbflags[slot] = txn->mt_dbs[slot].md_flags;
7211 mdb_default_cmp(txn, slot);
7220 int mdb_stat(MDB_txn *txn, MDB_dbi dbi, MDB_stat *arg)
7222 if (txn == NULL || arg == NULL || dbi >= txn->mt_numdbs)
7225 return mdb_stat0(txn->mt_env, &txn->mt_dbs[dbi], arg);
7228 void mdb_dbi_close(MDB_env *env, MDB_dbi dbi)
7231 if (dbi <= MAIN_DBI || dbi >= env->me_maxdbs)
7233 ptr = env->me_dbxs[dbi].md_name.mv_data;
7234 env->me_dbxs[dbi].md_name.mv_data = NULL;
7235 env->me_dbxs[dbi].md_name.mv_size = 0;
7236 env->me_dbflags[dbi] = 0;
7240 /** Add all the DB's pages to the free list.
7241 * @param[in] mc Cursor on the DB to free.
7242 * @param[in] subs non-Zero to check for sub-DBs in this DB.
7243 * @return 0 on success, non-zero on failure.
7246 mdb_drop0(MDB_cursor *mc, int subs)
7250 rc = mdb_page_search(mc, NULL, 0);
7251 if (rc == MDB_SUCCESS) {
7256 /* LEAF2 pages have no nodes, cannot have sub-DBs */
7257 if (IS_LEAF2(mc->mc_pg[mc->mc_top]))
7260 mdb_cursor_copy(mc, &mx);
7261 while (mc->mc_snum > 0) {
7262 if (IS_LEAF(mc->mc_pg[mc->mc_top])) {
7263 for (i=0; i<NUMKEYS(mc->mc_pg[mc->mc_top]); i++) {
7264 ni = NODEPTR(mc->mc_pg[mc->mc_top], i);
7265 if (ni->mn_flags & F_BIGDATA) {
7266 int j, ovpages = OVPAGES(NODEDSZ(ni), mc->mc_txn->mt_env->me_psize);
7268 memcpy(&pg, NODEDATA(ni), sizeof(pg));
7269 for (j=0; j<ovpages; j++) {
7270 mdb_midl_append(&mc->mc_txn->mt_free_pgs, pg);
7273 } else if (subs && (ni->mn_flags & F_SUBDATA)) {
7274 mdb_xcursor_init1(mc, ni);
7275 rc = mdb_drop0(&mc->mc_xcursor->mx_cursor, 0);
7281 for (i=0; i<NUMKEYS(mc->mc_pg[mc->mc_top]); i++) {
7283 ni = NODEPTR(mc->mc_pg[mc->mc_top], i);
7286 mdb_midl_append(&mc->mc_txn->mt_free_pgs, pg);
7291 mc->mc_ki[mc->mc_top] = i;
7292 rc = mdb_cursor_sibling(mc, 1);
7294 /* no more siblings, go back to beginning
7295 * of previous level.
7299 for (i=1; i<mc->mc_snum; i++) {
7301 mc->mc_pg[i] = mx.mc_pg[i];
7306 mdb_midl_append(&mc->mc_txn->mt_free_pgs,
7307 mc->mc_db->md_root);
7312 int mdb_drop(MDB_txn *txn, MDB_dbi dbi, int del)
7317 if (!txn || !dbi || dbi >= txn->mt_numdbs || (unsigned)del > 1 || !(txn->mt_dbflags[dbi] & DB_VALID))
7320 if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY))
7323 rc = mdb_cursor_open(txn, dbi, &mc);
7327 rc = mdb_drop0(mc, mc->mc_db->md_flags & MDB_DUPSORT);
7331 /* Can't delete the main DB */
7332 if (del && dbi > MAIN_DBI) {
7333 rc = mdb_del(txn, MAIN_DBI, &mc->mc_dbx->md_name, NULL);
7335 txn->mt_dbflags[dbi] = DB_STALE;
7336 mdb_dbi_close(txn->mt_env, dbi);
7339 /* reset the DB record, mark it dirty */
7340 txn->mt_dbflags[dbi] |= DB_DIRTY;
7341 txn->mt_dbs[dbi].md_depth = 0;
7342 txn->mt_dbs[dbi].md_branch_pages = 0;
7343 txn->mt_dbs[dbi].md_leaf_pages = 0;
7344 txn->mt_dbs[dbi].md_overflow_pages = 0;
7345 txn->mt_dbs[dbi].md_entries = 0;
7346 txn->mt_dbs[dbi].md_root = P_INVALID;
7348 txn->mt_flags |= MDB_TXN_DIRTY;
7351 mdb_cursor_close(mc);
7355 int mdb_set_compare(MDB_txn *txn, MDB_dbi dbi, MDB_cmp_func *cmp)
7357 if (txn == NULL || !dbi || dbi >= txn->mt_numdbs || !(txn->mt_dbflags[dbi] & DB_VALID))
7360 txn->mt_dbxs[dbi].md_cmp = cmp;
7364 int mdb_set_dupsort(MDB_txn *txn, MDB_dbi dbi, MDB_cmp_func *cmp)
7366 if (txn == NULL || !dbi || dbi >= txn->mt_numdbs || !(txn->mt_dbflags[dbi] & DB_VALID))
7369 txn->mt_dbxs[dbi].md_dcmp = cmp;
7373 int mdb_set_relfunc(MDB_txn *txn, MDB_dbi dbi, MDB_rel_func *rel)
7375 if (txn == NULL || !dbi || dbi >= txn->mt_numdbs || !(txn->mt_dbflags[dbi] & DB_VALID))
7378 txn->mt_dbxs[dbi].md_rel = rel;
7382 int mdb_set_relctx(MDB_txn *txn, MDB_dbi dbi, void *ctx)
7384 if (txn == NULL || !dbi || dbi >= txn->mt_numdbs || !(txn->mt_dbflags[dbi] & DB_VALID))
7387 txn->mt_dbxs[dbi].md_relctx = ctx;
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