1 .TH SLAPD-BDB 5 "RELEASEDATE" "OpenLDAP LDVERSION"
2 .\" Copyright 1998-2009 The OpenLDAP Foundation All Rights Reserved.
3 .\" Copying restrictions apply. See COPYRIGHT/LICENSE.
6 slapd\-bdb, slapd\-hdb \- Berkeley DB backends to slapd
10 The \fBbdb\fP backend to
12 is the recommended primary backend for a normal
15 It uses the Oracle Berkeley DB (BDB) package to store data.
16 It makes extensive use of indexing and caching to speed data access.
18 \fBhdb\fP is a variant of the \fBbdb\fP backend that uses a
20 layout which supports subtree renames. It is otherwise identical to
21 the \fBbdb\fP behavior, and all the same configuration options apply.
23 It is noted that these options are intended to complement
24 Berkeley DB configuration options set in the environment's
26 file. See Berkeley DB documentation for details on
28 configuration options.
29 Where there is overlap, settings in
35 options apply to the \fBbdb\fP and \fBhdb\fP backend database.
36 That is, they must follow a "database bdb" or "database hdb" line and
37 come before any subsequent "backend" or "database" lines.
38 Other database options are described in the
42 .BI cachesize \ <integer>
43 Specify the size in entries of the in-memory entry cache maintained
44 by the \fBbdb\fP or \fBhdb\fP backend database instance.
45 The default is 1000 entries.
47 .BI cachefree \ <integer>
48 Specify the number of entries to free from the entry cache when the
49 cache reaches the \fBcachesize\fP limit.
50 The default is 1 entry.
52 .BI checkpoint \ <kbyte>\ <min>
53 Specify the frequency for checkpointing the database transaction log.
54 A checkpoint operation flushes the database buffers to disk and writes
55 a checkpoint record in the log.
56 The checkpoint will occur if either \fI<kbyte>\fP data has been written or
57 \fI<min>\fP minutes have passed since the last checkpoint.
58 Both arguments default to zero, in which case they are ignored. When
59 the \fI<min>\fP argument is non-zero, an internal task will run every
60 \fI<min>\fP minutes to perform the checkpoint.
61 See the Berkeley DB reference guide for more details.
64 Enable checksum validation of DB pages whenever they are read from disk.
65 This setting can only be configured before any database files are created.
67 .BI cryptfile \ <file>
68 Specify the pathname of a file containing an encryption key to use for
69 encrypting the database. Encryption is performed using Berkeley DB's
70 implementation of AES. Note that encryption can only be configured before
71 any database files are created, and changing the key can only be done
72 after destroying the current database and recreating it. Encryption is
73 not enabled by default, and some distributions of Berkeley DB do not
77 Specify an encryption key to use for encrypting the database. This option
78 may be used when a separate
80 is not desired. Only one of
86 .BI dbconfig \ <Berkeley-DB-setting>
87 Specify a configuration directive to be placed in the
89 file of the database directory. The
91 directive is just a convenience
92 to allow all necessary configuration to be set in the
95 The options set using this directive will only be written to the
97 file if no such file existed at server startup time, otherwise
98 they are completely ignored. This allows one
99 to set initial values without overwriting/destroying a
101 file that was already customized through other means.
102 This directive may be specified multiple times, as needed.
106 dbconfig set_cachesize 0 1048576 0
107 dbconfig set_lg_bsize 2097152
112 Specify that on-disk database contents should not be immediately
113 synchronized with in memory changes.
114 Enabling this option may improve performance at the expense of data
116 See the Berkeley DB reference guide for more details.
118 \fBdbpagesize \fR \fI<dbfile> <size>\fR
119 Specify the page size to use for a particular database file, in units
120 of 1024 bytes. The default for the
122 file is 16, the default for all other files depends on the size of the
123 underlying filesystem's block size (typically 4 or 8).
124 The maximum that BerkeleyDB supports is 64. This
125 setting usually should not need to be changed, but if BerkeleyDB's
126 "db_stat \-d" shows a large amount of overflow pages in use in a file,
127 setting a larger size may increase performance at the expense of
128 data integrity. This setting only takes effect when a database is
129 being newly created. See the Berkeley DB reference guide for more details.
131 .BI directory \ <directory>
132 Specify the directory where the BDB files containing this database and
133 associated indexes live.
134 A separate directory must be specified for each database.
136 .BR LOCALSTATEDIR/openldap\-data .
139 Allow reads of modified but not yet committed data.
140 Usually transactions are isolated to prevent other operations from
141 accessing uncommitted data.
142 This option may improve performance, but may also return inconsistent
143 results if the data comes from a transaction that is later aborted.
144 In this case, the modified data is discarded and a subsequent search
145 will return a different result.
147 .BI dncachesize \ <integer>
148 Specify the maximum number of DNs in the in-memory DN cache. The
149 default is twice the \fBcachesize\fP. Ideally this cache should be
150 large enough to contain the DNs of every entry in the database. If
151 set to a smaller value than the \fBcachesize\fP it will be silently
152 increased to equal the \fBcachesize\fP.
154 It should be noted that the \fBDN cache\fP is allowed to temporarily
155 grow beyond the configured size. It does this if many entries are
156 locked when it tries to do a purge, because that means they're
157 legitimately in use. Also, the \fBDN cache\fP never purges entries
158 that have cached children, so depending on the shape of the DIT, it
159 could have lots of cached DNs over the defined limit.
161 .BI idlcachesize \ <integer>
162 Specify the size of the in-memory index cache, in index slots. The
163 default is zero. A larger value will speed up frequent searches of
164 indexed entries. An \fBhdb\fP database needs a large \fBidlcachesize\fP
165 for good search performance, typically three times the
170 \fBindex \fR{\fI<attrlist>\fR|\fBdefault\fR} [\fBpres\fR,\fBeq\fR,\fBapprox\fR,\fBsub\fR,\fI<special>\fR]
171 Specify the indexes to maintain for the given attribute (or
173 Some attributes only support a subset of indexes.
174 If only an \fI<attr>\fP is given, the indices specified for \fBdefault\fR
176 Note that setting a default does not imply that all attributes will be
177 indexed. Also, for best performance, an
179 index should always be configured for the
183 A number of special index parameters may be specified.
186 can be decomposed into
193 may be specified to disallow use of this index by language subtypes.
196 may be specified to disallow use of this index by named subtypes.
197 Note: changing \fBindex\fP settings in
199 requires rebuilding indices, see
201 changing \fBindex\fP settings
202 dynamically by LDAPModifying "cn=config" automatically causes rebuilding
203 of the indices online in a background task.
208 to index one attribute at a time. By default, all indexed
209 attributes in an entry are processed at the same time. With this option,
210 each indexed attribute is processed individually, using multiple passes
211 through the entire database. This option improves
214 when the database size exceeds the \fBdbcache\fP size. When the \fBdbcache\fP is
215 large enough, this option is not needed and will decrease performance.
218 performs full indexing and so a separate
220 run is not needed. With this option,
226 .BR lockdetect \ { oldest | youngest | fewest | random | default }
227 Specify which transaction to abort when a deadlock is detected.
232 Specify the file protection mode that newly created database
233 index files should have.
236 .BI searchstack \ <depth>
237 Specify the depth of the stack used for search filter evaluation.
238 Search filters are evaluated on a stack to accommodate nested AND / OR
239 clauses. An individual stack is assigned to each server thread.
240 The depth of the stack determines how complex a filter can be
241 evaluated without requiring any additional memory allocation. Filters that
242 are nested deeper than the search stack depth will cause a separate
243 stack to be allocated for that particular search operation. These
244 allocations can have a major negative impact on server performance,
245 but specifying too much stack will also consume a great deal of memory.
246 Each search stack uses 512K bytes per level. The default stack depth
247 is 16, thus 8MB per thread is used.
249 .BI shm_key \ <integer>
250 Specify a key for a shared memory BDB environment. By default the
251 BDB environment uses memory mapped files. If a non-zero value is
252 specified, it will be used as the key to identify a shared memory
253 region that will house the environment.
259 backends honor access control semantics as indicated in
260 .BR slapd.access (5).
269 Berkeley DB configuration file
272 .BR slapd\-config (5),
277 Berkeley DB documentation.
280 Originally begun by Kurt Zeilenga. Caching mechanisms originally designed
281 by Jong-Hyuk Choi. Completion and subsequent work, as well as
282 back-hdb, by Howard Chu.
projects / openldap / blob