LMDB_TABLE(5) LMDB_TABLE(5) NAME lmdb_table - Postfix LMDB adapter SYNOPSIS postmap lmdb:/etc/postfix/filename postmap -i lmdb:/etc/postfix/filename <inputfile postmap -d "key" lmdb:/etc/postfix/filename postmap -d - lmdb:/etc/postfix/filename <inputfile postmap -q "key" lmdb:/etc/postfix/filename postmap -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 lim- ited only by the size of the memory address space and file system. REQUESTS The LMDB adapter supports all Postfix lookup table opera- tions. This makes LMDB suitable for Postfix address rewriting, routing, access policies, caches, or any infor- mation that can be stored under a fixed lookup key. When a transaction fails due to a full database, Postfix resizes the database and retries the transaction. Postfix access, address mapping and routing tables will generate partial search keys such as domain names without one or more subdomains, network addresses without one or more least-significant octets, or email addresses without the localpart, address extension or domain portion. This behavior is also found with btree:, hash:, or ldap: tables. Unlike other flat-file based Postfix databases, changes to an LMDB database do not require automatic daemon program restart. RELIABILITY LMDB's copy-on-write architecture achieves reliable 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 curruption due stray pointer bugs. The Postfix LMDB adapter implements locking with fcntl(2) locks at whole-file granularity. LMDB's native locking scheme would require world-writable lockfiles and would therefore violate the Postfix security model. Unlike some other Postfix flat-file databases, LMDB databases can safely be updated without serializing requests through the proxymap(8) service. CONFIGURATION PARAMETERS Short-lived programs automatically pick up changes to main.cf. With long-running daemon programs, Use the com- mand "postfix reload" after a configuration change. lmdb_map_size (default: 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 DATABASE_README, Postfix lookup table overview LMDB_README, Postfix 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 LMDB_TABLE(5)