CDB_README.html revision 1.1.1.2
1 1.1 tron <!doctype html public "-//W3C//DTD HTML 4.01 Transitional//EN" 2 1.1 tron "http://www.w3.org/TR/html4/loose.dtd"> 3 1.1 tron 4 1.1 tron <html> 5 1.1 tron 6 1.1 tron <head> 7 1.1 tron 8 1.1 tron <title>Postfix CDB Howto</title> 9 1.1 tron 10 1.1 tron <meta http-equiv="Content-Type" content="text/html; charset=us-ascii"> 11 1.1 tron 12 1.1 tron </head> 13 1.1 tron 14 1.1 tron <body> 15 1.1 tron 16 1.1 tron <h1><img src="postfix-logo.jpg" width="203" height="98" ALT="">Postfix CDB Howto</h1> 17 1.1 tron 18 1.1 tron <hr> 19 1.1 tron 20 1.1 tron <h2>Introduction</h2> 21 1.1 tron 22 1.1 tron <p> CDB (Constant DataBase) is an indexed file format designed by 23 1.1 tron Daniel Bernstein. CDB is optimized exclusively for read access 24 1.1 tron and guarantees that each record will be read in at most two disk 25 1.1 tron accesses. This is achieved by forgoing support for incremental 26 1.1 tron updates: no single-record inserts or deletes are supported. CDB 27 1.1 tron databases can be modified only by rebuilding them completely from 28 1.1 tron scratch, hence the "constant" qualifier in the name. </p> 29 1.1 tron 30 1.1 tron <p> Postfix CDB databases are specified as "<a href="CDB_README.html">cdb</a>:<i>name</i>", where 31 1.1 tron <i>name</i> specifies the CDB file name without the ".cdb" suffix 32 1.1 tron (another suffix, ".tmp", is used temporarily while a CDB file is 33 1.1 tron under construction). CDB databases are maintained with the <a href="postmap.1.html">postmap(1)</a> 34 1.1 tron or <a href="postalias.1.html">postalias(1)</a> command. The <a href="DATABASE_README.html">DATABASE_README</a> document has general 35 1.1 tron information about Postfix databases. </p> 36 1.1 tron 37 1.1 tron <p> CDB support is available with Postfix 2.2 and later releases. 38 1.1 tron This document describes how to build Postfix with CDB support. </p> 39 1.1 tron 40 1.1 tron <h2>Building Postfix with CDB support</h2> 41 1.1 tron 42 1.1 tron <p> These instructions assume that you build Postfix from source 43 1.1 tron code as described in the <a href="INSTALL.html">INSTALL</a> document. Some modification may 44 1.1 tron be required if you build Postfix from a vendor-specific source 45 1.1 tron package. </p> 46 1.1 tron 47 1.1 tron <p> Postfix is compatible with two CDB implementations: </p> 48 1.1 tron 49 1.1 tron <ul> 50 1.1 tron 51 1.1 tron <li> <p> The original cdb library from Daniel Bernstein, available 52 1.1 tron from <a href="http://cr.yp.to/cdb.html">http://cr.yp.to/cdb.html</a>, and </p> 53 1.1 tron 54 1.1 tron <li> <p> tinycdb (version 0.5 and later) from Michael Tokarev, 55 1.1 tron available from <a href="http://www.corpit.ru/mjt/tinycdb.html">http://www.corpit.ru/mjt/tinycdb.html</a>. </p> 56 1.1 tron 57 1.1 tron </ul> 58 1.1 tron 59 1.1 tron <p> Tinycdb is preferred, since it is a bit faster, has additional 60 1.1 tron useful functionality and is much simpler to use. </p> 61 1.1 tron 62 1.1 tron <p>To build Postfix after you have installed tinycdb, use something 63 1.1 tron like: </p> 64 1.1 tron 65 1.1 tron <blockquote> 66 1.1 tron <pre> 67 1.1 tron % make tidy 68 1.1 tron % CDB=../../../tinycdb-0.5 69 1.1 tron % make -f Makefile.init makefiles "CCARGS=-DHAS_CDB -I$CDB" \ 70 1.1.1.2 christos "<a href="CDB_README.html">AUXLIBS_CDB</a>=$CDB/libcdb.a" 71 1.1 tron % make 72 1.1 tron </pre> 73 1.1 tron </blockquote> 74 1.1 tron 75 1.1 tron <p> Alternatively, for the D.J.B. version of CDB:<p> 76 1.1 tron 77 1.1 tron <blockquote> 78 1.1 tron <pre> 79 1.1 tron % make tidy 80 1.1 tron % CDB=../../../cdb-0.75 81 1.1 tron % make -f Makefile.init makefiles "CCARGS=-DHAS_CDB -I$CDB" \ 82 1.1.1.2 christos "<a href="CDB_README.html">AUXLIBS_CDB</a>=$CDB/cdb.a $CDB/alloc.a $CDB/buffer.a $CDB/unix.a $CDB/byte.a" 83 1.1 tron % make 84 1.1 tron </pre> 85 1.1 tron </blockquote> 86 1.1 tron 87 1.1.1.2 christos <p> Postfix versions before 3.0 use AUXLIBS instead of <a href="CDB_README.html">AUXLIBS_CDB</a>. 88 1.1.1.2 christos With Postfix 3.0 and later, the old AUXLIBS variable still supports 89 1.1.1.2 christos building a statically-loaded CDB database client, but only the new 90 1.1.1.2 christos <a href="CDB_README.html">AUXLIBS_CDB</a> variable supports building a dynamically-loaded or 91 1.1.1.2 christos statically-loaded CDB database client. </p> 92 1.1.1.2 christos 93 1.1.1.2 christos <blockquote> 94 1.1.1.2 christos 95 1.1.1.2 christos <p> Failure to use the <a href="CDB_README.html">AUXLIBS_CDB</a> variable will defeat the purpose 96 1.1.1.2 christos of dynamic database client loading. Every Postfix executable file 97 1.1.1.2 christos will have CDB database library dependencies. And that was exactly 98 1.1.1.2 christos what dynamic database client loading was meant to avoid. </p> 99 1.1.1.2 christos 100 1.1.1.2 christos </blockquote> 101 1.1.1.2 christos 102 1.1 tron <p> After Postfix has been built with cdb support, you can use 103 1.1 tron "cdb" tables wherever you can use read-only "hash", "btree" or 104 1.1 tron "dbm" tables. However, the "<b>postmap -i</b>" (incremental record 105 1.1 tron insertion) and "<b>postmap -d</b>" (incremental record deletion) 106 1.1 tron command-line options are not available. For the same reason the 107 1.1 tron "cdb" map type cannot be used to store the persistent address 108 1.1 tron verification cache for the <a href="verify.8.html">verify(8)</a> service, or to store 109 1.1 tron TLS session information for the <a href="tlsmgr.8.html">tlsmgr(8)</a> service. </p> 110
Indexes created Thu Sep 24 00:25:51 UTC 2026