.TH SLAPD-BDB 5 "RELEASEDATE" "OpenLDAP LDVERSION" .\" Copyright 1998-2005 The OpenLDAP Foundation All Rights Reserved. .\" Copying restrictions apply. See COPYRIGHT/LICENSE. .\" $OpenLDAP$ .SH NAME slapd-bdb, slapd-hdb \- Berkeley DB backends to slapd .SH SYNOPSIS ETCDIR/slapd.conf .SH DESCRIPTION The BDB backend to .BR slapd (8) is the recommended backend for a normal slapd database. However, it takes more care than with the LDBM backend to configure it properly. It uses the Sleepycat Berkeley DB (BDB) package to store data. It makes extensive use of indexing and caching to speed data access. .LP "hdb" is a variant of the BDB backend that uses a hierarchical database layout which supports subtree renames. It is otherwise identical to the "bdb" behavior, and all the same configuration options apply. .LP It is noted that these options are intended to complement Berkeley DB configuration options set in the environment's .B DB_CONFIG file. See Berkeley DB documentation for details on .B DB_CONFIG configuration options. Where there is overlap, settings in .B DB_CONFIG take precedence. .SH CONFIGURATION These .B slapd.conf options apply to the BDB backend database. That is, they must follow a "database bdb" or "database hdb" line and come before any subsequent "backend" or "database" lines. Other database options are described in the .BR slapd.conf (5) manual page. .TP .B cachesize Specify the size in entries of the in-memory entry cache maintained by the BDB backend database instance. The default is 1000 entries. .TP .B checkpoint Specify the frequency for checkpointing the database transaction log. A checkpoint operation flushes the database buffers to disk and writes a checkpoint record in the log. The checkpoint will occur if either data has been written or minutes have passed since the last checkpoint. Both arguments default to zero, in which case they are ignored. When the argument is non-zero, an internal task will run every minutes to perform the checkpoint. See the Berkeley DB reference guide for more details. .TP .B dbconfig Specify a configuration directive to be placed in the .B DB_CONFIG file of the database directory. The .B dbconfig directive is just a convenience to allow all necessary configuration to be set in the .B slapd.conf file. The options set using this directive will only be written to the DB_CONFIG file if no such file existed at server startup time. This allows one to set initial values without overwriting/destroying a DB_CONFIG file that was already customized through other means. This directive may be specified multiple times, as needed. For example .RS .nf dbconfig set_cachesize 0 1048576 0 dbconfig set_lg_bsize 2097152 .fi .RE .TP .B dbnosync Specify that on-disk database contents should not be immediately synchronized with in memory changes. Enabling this option may improve performance at the expense of data security. See the Berkeley DB reference guide for more details. .TP .B directory Specify the directory where the BDB files containing this database and associated indexes live. A separate directory must be specified for each database. The default is .BR LOCALSTATEDIR/openldap-data . .TP .B dirtyread Allow reads of modified but not yet committed data. Usually transactions are isolated to prevent other operations from accessing uncommitted data. This option may improve performance, but may also return inconsistent results if the data comes from a transaction that is later aborted. In this case, the modified data is discarded and a subsequent search will return a different result. .TP .B idlcachesize Specify the size of the in-memory index cache, in index slots. The default is zero. A larger value will speed up frequent searches of indexed entries. An hdb database needs a large idlcachesize for good search performance, typically three times the entry cache size or larger. .TP .B index {|default} [pres,eq,approx,sub,] Specify the indexes to maintain for the given attribute (or list of attributes). Some attributes only support a subset of indexes. If only an is given, the indices specified for \fBdefault\fR are maintained. Note that setting a default does not imply that all attributes will be indexed. Also, for best performance, an .B eq index should always be configured for the .B objectClass attribute. A number of special index parameters may be specified. The index type .B sub can be decomposed into .BR subinitial , .BR subany ,\ and .B subfinal indices. The special type .B nolang may be specified to disallow use of this index by language subtypes. The special type .B nosubtypes may be specified to disallow use of this index by named subtypes. Note: changing index settings requires rebuilding indices, see .BR slapindex (8). .TP .B linearindex Tell slapindex to index one attribute at a time. By default, all indexed attributes in an entry are processed at the same time. With this option, each indexed attribute is processed individually, using multiple passes through the entire database. This option improves slapindex performance when the database size exceeds the dbcache size. When the dbcache is large enough, this option is not needed and will decrease performance. Also by default, slapadd performs full indexing and so a separate slapindex run is not needed. With this option, slapadd does no indexing and slapindex must be used. .TP .B lockdetect {oldest|youngest|fewest|random|default} Specify which transaction to abort when a deadlock is detected. The default is the same as .BR random . .TP .B mode Specify the file protection mode that newly created database index files should have. The default is 0600. .TP .B searchstack Specify the depth of the stack used for search filter evaluation. Search filters are evaluated on a stack to accommodate nested AND / OR clauses. An individual stack is assigned to each server thread. The depth of the stack determines how complex a filter can be evaluated without requiring any additional memory allocation. Filters that are nested deeper than the search stack depth will cause a separate stack to be allocated for that particular search operation. These allocations can have a major negative impact on server performance, but specifying too much stack will also consume a great deal of memory. Each search stack uses 512K bytes per level. The default stack depth is 16, thus 8MB per thread is used. .TP .B shm_key Specify a key for a shared memory BDB environment. By default the BDB environment uses memory mapped files. If a non-zero value is specified, it will be used as the key to identify a shared memory region that will house the environment. .SH ACCESS CONTROL The .B bdb and .B hdb backends honor access control semantics as indicated in .BR slapd.access (5). .SH FILES .TP ETCDIR/slapd.conf default slapd configuration file .TP DB_CONFIG Berkeley DB configuration file .SH SEE ALSO .BR slapd.conf (5), .BR slapd (8), .BR slapadd (8), .BR slapcat (8), .BR slapindex (8), Berkeley DB documentation.