Postfix CDB Howto
CDB (Constant DataBase) is an indexed file format designed by
Daniel Bernstein. CDB is optimized exclusively for read access
and guarantees that each record will be read in at most two disk
accesses. This is achieved by forgoing support for incremental
updates: no single-record inserts or deletes are supported. CDB
databases can be modified only by rebuilding them completely from
scratch, hence the "constant" qualifier in the name.
Postfix CDB databases are specified as "cdb:name", where
name specifies the CDB file name without the ".cdb" suffix
(another suffix, ".tmp", is used temporarily while a CDB file is
under construction). CDB databases are maintained with the
postalias(1) command. The
DATABASE_README document has general
information about Postfix databases.
CDB support is available with Postfix 2.2 and later releases.
This document describes how to build Postfix with CDB support.