CDB_README.html revision 1.1.1.5
1 1.1 tron <!doctype html public "-//W3C//DTD HTML 4.01 Transitional//EN" 2 1.1.1.5 christos "https://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 1.1.1.3 christos <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> 11 1.1.1.4 christos <link rel='stylesheet' type='text/css' href='postfix-doc.css'> 12 1.1 tron 13 1.1 tron </head> 14 1.1 tron 15 1.1 tron <body> 16 1.1 tron 17 1.1 tron <h1><img src="postfix-logo.jpg" width="203" height="98" ALT="">Postfix CDB Howto</h1> 18 1.1 tron 19 1.1 tron <hr> 20 1.1 tron 21 1.1 tron <h2>Introduction</h2> 22 1.1 tron 23 1.1 tron <p> CDB (Constant DataBase) is an indexed file format designed by 24 1.1 tron Daniel Bernstein. CDB is optimized exclusively for read access 25 1.1 tron and guarantees that each record will be read in at most two disk 26 1.1 tron accesses. This is achieved by forgoing support for incremental 27 1.1 tron updates: no single-record inserts or deletes are supported. CDB 28 1.1 tron databases can be modified only by rebuilding them completely from 29 1.1 tron scratch, hence the "constant" qualifier in the name. </p> 30 1.1 tron 31 1.1 tron <p> Postfix CDB databases are specified as "<a href="CDB_README.html">cdb</a>:<i>name</i>", where 32 1.1 tron <i>name</i> specifies the CDB file name without the ".cdb" suffix 33 1.1 tron (another suffix, ".tmp", is used temporarily while a CDB file is 34 1.1 tron under construction). CDB databases are maintained with the <a href="postmap.1.html">postmap(1)</a> 35 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 36 1.1 tron information about Postfix databases. </p> 37 1.1 tron 38 1.1.1.5 christos <p> You can use "<a href="CDB_README.html">cdb</a>:" tables wherever you can use read-only "hash", 39 1.1.1.5 christos "btree" or "lmdb" tables with the following limitations: </p> 40 1.1.1.5 christos 41 1.1.1.5 christos <ul> 42 1.1.1.5 christos 43 1.1.1.5 christos <li> <p> CDB databases cannot be larger than 4GB on LP64 and ILP32 44 1.1.1.5 christos systems, because the CDB library API uses unsigned integers for 45 1.1.1.5 christos file offsets. </p> 46 1.1.1.5 christos 47 1.1.1.5 christos <li> <p> The "<b>postmap -i</b>" (incremental record insertion) and 48 1.1.1.5 christos "<b>postmap -d</b>" (incremental record deletion) command-line 49 1.1.1.5 christos options are not available. For the same reason the "<a href="CDB_README.html">cdb</a>:" map type 50 1.1.1.5 christos cannot be used to for persistent caches, such as the address 51 1.1.1.5 christos verification cache for the <a href="verify.8.html">verify(8)</a> service, the TLS session cache 52 1.1.1.5 christos for the <a href="tlsmgr.8.html">tlsmgr(8)</a> service, or the dynamic allowlist for <a href="postscreen.8.html">postscreen(8)</a>. 53 1.1.1.5 christos </p> 54 1.1.1.5 christos 55 1.1.1.5 christos <li> <p> The "sequence" operation ("<b>postmap -s</b>" or "<b>postalias 56 1.1.1.5 christos -s</b>") is available only wen Postfix is built with tinycdb by 57 1.1.1.5 christos Michael Tokarev, not with the original cdb library by Daniel Bernstein. 58 1.1.1.5 christos </p> 59 1.1.1.5 christos 60 1.1.1.5 christos </ul> 61 1.1.1.5 christos 62 1.1 tron <p> CDB support is available with Postfix 2.2 and later releases. 63 1.1.1.5 christos The remainder of this document describes how to build Postfix with 64 1.1.1.5 christos CDB support. </p> 65 1.1 tron 66 1.1 tron <h2>Building Postfix with CDB support</h2> 67 1.1 tron 68 1.1 tron <p> These instructions assume that you build Postfix from source 69 1.1 tron code as described in the <a href="INSTALL.html">INSTALL</a> document. Some modification may 70 1.1 tron be required if you build Postfix from a vendor-specific source 71 1.1 tron package. </p> 72 1.1 tron 73 1.1 tron <p> Postfix is compatible with two CDB implementations: </p> 74 1.1 tron 75 1.1 tron <ul> 76 1.1 tron 77 1.1 tron <li> <p> The original cdb library from Daniel Bernstein, available 78 1.1.1.5 christos from <a href="https://cr.yp.to/cdb.html">https://cr.yp.to/cdb.html</a>, and </p> 79 1.1 tron 80 1.1 tron <li> <p> tinycdb (version 0.5 and later) from Michael Tokarev, 81 1.1.1.5 christos available from <a href="https://www.corpit.ru/mjt/tinycdb.html">https://www.corpit.ru/mjt/tinycdb.html</a>. </p> 82 1.1 tron 83 1.1 tron </ul> 84 1.1 tron 85 1.1 tron <p> Tinycdb is preferred, since it is a bit faster, has additional 86 1.1 tron useful functionality and is much simpler to use. </p> 87 1.1 tron 88 1.1 tron <p>To build Postfix after you have installed tinycdb, use something 89 1.1 tron like: </p> 90 1.1 tron 91 1.1 tron <blockquote> 92 1.1 tron <pre> 93 1.1 tron % make tidy 94 1.1 tron % CDB=../../../tinycdb-0.5 95 1.1 tron % make -f Makefile.init makefiles "CCARGS=-DHAS_CDB -I$CDB" \ 96 1.1.1.2 christos "<a href="CDB_README.html">AUXLIBS_CDB</a>=$CDB/libcdb.a" 97 1.1 tron % make 98 1.1 tron </pre> 99 1.1 tron </blockquote> 100 1.1 tron 101 1.1 tron <p> Alternatively, for the D.J.B. version of CDB:<p> 102 1.1 tron 103 1.1 tron <blockquote> 104 1.1 tron <pre> 105 1.1 tron % make tidy 106 1.1 tron % CDB=../../../cdb-0.75 107 1.1 tron % make -f Makefile.init makefiles "CCARGS=-DHAS_CDB -I$CDB" \ 108 1.1.1.2 christos "<a href="CDB_README.html">AUXLIBS_CDB</a>=$CDB/cdb.a $CDB/alloc.a $CDB/buffer.a $CDB/unix.a $CDB/byte.a" 109 1.1 tron % make 110 1.1 tron </pre> 111 1.1 tron </blockquote> 112 1.1 tron 113 1.1.1.2 christos <p> Postfix versions before 3.0 use AUXLIBS instead of <a href="CDB_README.html">AUXLIBS_CDB</a>. 114 1.1.1.2 christos With Postfix 3.0 and later, the old AUXLIBS variable still supports 115 1.1.1.2 christos building a statically-loaded CDB database client, but only the new 116 1.1.1.2 christos <a href="CDB_README.html">AUXLIBS_CDB</a> variable supports building a dynamically-loaded or 117 1.1.1.2 christos statically-loaded CDB database client. </p> 118 1.1.1.2 christos 119 1.1.1.2 christos <blockquote> 120 1.1.1.2 christos 121 1.1.1.2 christos <p> Failure to use the <a href="CDB_README.html">AUXLIBS_CDB</a> variable will defeat the purpose 122 1.1.1.2 christos of dynamic database client loading. Every Postfix executable file 123 1.1.1.2 christos will have CDB database library dependencies. And that was exactly 124 1.1.1.2 christos what dynamic database client loading was meant to avoid. </p> 125 1.1.1.2 christos 126 1.1.1.2 christos </blockquote> 127
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