NAME
lmdb_table - Postfix LMDB adapterSYNOPSIS
postmap lmdb:/etc/postfix/filenamepostmap -i lmdb:/etc/postfix/filename <inputfile postmap -d "key" lmdb:/etc/postfix/filenamepostmap -d - lmdb:/etc/postfix/filename <inputfile postmap -q "key" lmdb:/etc/postfix/filenamepostmap -q - lmdb:/etc/postfix/filename <inputfile
DESCRIPTION
The Postfix LMDB adapter provides access to a persistent, memory-mapped, key-value store. The database size is limited only by the size of the memory address space (typically 31 or 47 bits on 32-bit or 64-bit CPUs, respectively) and by the available file system space.
REQUESTS
The LMDB adapter supports all Postfix lookup table operations. This makes LMDB suitable for Postfix address rewriting, routing, access policies, caches, or any information that can be stored under a fixed lookup key.
RELIABILITY
LMDB's copy-on-write architecture provides safe updates, at the cost of using more space than some other flat-file databases. Read operations are memory-mapped for speed. Write operations are not memory-mapped to avoid silent corruption due to stray pointer bugs.
SYNCHRONIZATION
The Postfix LMDB adapter does not use LMDB's built-in locking scheme, because that would require world-writable lockfiles and would violate the Postfix security model. Instead, Postfix uses fcntl(2) locks with whole-file granularity. Programs that use LMDB's built-in locking protocol will corrupt a Postfix LMDB database or will read garbage.
CONFIGURATION PARAMETERS
Short-lived programs automatically pick up changes to main.cf. With long-running daemon programs, Use the command " postfix reload" after a configuration change.
- lmdb_map_size (16777216)
- The initial OpenLDAP LMDB database size limit in bytes.
SEE ALSO
postconf(1), Postfix supported lookup tables postmap(1), Postfix lookup table maintenance postconf(5), configuration parameters
README FILES
Use " postconf readme_directory" or " postconf html_directory" to locate this information.
DATABASE_README, Postfix lookup table overview LMDB_README, Postfix OpenLDAP LMDB howto
LICENSE
The Secure Mailer license must be distributed with this software.
HISTORY
LMDB support was introduced with Postfix version 2.11.
AUTHOR(S)
Howard Chu Symas Corporation Wietse Venema IBM T.J. Watson Research P.O. Box 704 Yorktown Heights, NY 10598, USA Wietse Venema Google, Inc. 111 8th Avenue New York, NY 10011, USA