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diff --git a/html/CDB_README.html b/html/CDB_README.html new file mode 100644 index 0000000..6997a14 --- /dev/null +++ b/html/CDB_README.html @@ -0,0 +1,109 @@ +<!doctype html public "-//W3C//DTD HTML 4.01 Transitional//EN" + "http://www.w3.org/TR/html4/loose.dtd"> + +<html> + +<head> + +<title>Postfix CDB Howto</title> + +<meta http-equiv="Content-Type" content="text/html; charset=us-ascii"> + +</head> + +<body> + +<h1><img src="postfix-logo.jpg" width="203" height="98" ALT="">Postfix CDB Howto</h1> + +<hr> + +<h2>Introduction</h2> + +<p> 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. </p> + +<p> Postfix CDB databases are specified as "<a href="CDB_README.html">cdb</a>:<i>name</i>", where +<i>name</i> 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 <a href="postmap.1.html">postmap(1)</a> +or <a href="postalias.1.html">postalias(1)</a> command. The <a href="DATABASE_README.html">DATABASE_README</a> document has general +information about Postfix databases. </p> + +<p> CDB support is available with Postfix 2.2 and later releases. +This document describes how to build Postfix with CDB support. </p> + +<h2>Building Postfix with CDB support</h2> + +<p> These instructions assume that you build Postfix from source +code as described in the <a href="INSTALL.html">INSTALL</a> document. Some modification may +be required if you build Postfix from a vendor-specific source +package. </p> + +<p> Postfix is compatible with two CDB implementations: </p> + +<ul> + +<li> <p> The original cdb library from Daniel Bernstein, available +from <a href="http://cr.yp.to/cdb.html">http://cr.yp.to/cdb.html</a>, and </p> + +<li> <p> tinycdb (version 0.5 and later) from Michael Tokarev, +available from <a href="http://www.corpit.ru/mjt/tinycdb.html">http://www.corpit.ru/mjt/tinycdb.html</a>. </p> + +</ul> + +<p> Tinycdb is preferred, since it is a bit faster, has additional +useful functionality and is much simpler to use. </p> + +<p>To build Postfix after you have installed tinycdb, use something +like: </p> + +<blockquote> +<pre> +% make tidy +% CDB=../../../tinycdb-0.5 +% make -f Makefile.init makefiles "CCARGS=-DHAS_CDB -I$CDB" \ + "<a href="CDB_README.html">AUXLIBS_CDB</a>=$CDB/libcdb.a" +% make +</pre> +</blockquote> + +<p> Alternatively, for the D.J.B. version of CDB:<p> + +<blockquote> +<pre> +% make tidy +% CDB=../../../cdb-0.75 +% make -f Makefile.init makefiles "CCARGS=-DHAS_CDB -I$CDB" \ + "<a href="CDB_README.html">AUXLIBS_CDB</a>=$CDB/cdb.a $CDB/alloc.a $CDB/buffer.a $CDB/unix.a $CDB/byte.a" +% make +</pre> +</blockquote> + +<p> Postfix versions before 3.0 use AUXLIBS instead of <a href="CDB_README.html">AUXLIBS_CDB</a>. +With Postfix 3.0 and later, the old AUXLIBS variable still supports +building a statically-loaded CDB database client, but only the new +<a href="CDB_README.html">AUXLIBS_CDB</a> variable supports building a dynamically-loaded or +statically-loaded CDB database client. </p> + +<blockquote> + +<p> Failure to use the <a href="CDB_README.html">AUXLIBS_CDB</a> variable will defeat the purpose +of dynamic database client loading. Every Postfix executable file +will have CDB database library dependencies. And that was exactly +what dynamic database client loading was meant to avoid. </p> + +</blockquote> + +<p> After Postfix has been built with cdb support, you can use +"cdb" tables wherever you can use read-only "hash", "btree" or +"dbm" tables. However, the "<b>postmap -i</b>" (incremental record +insertion) and "<b>postmap -d</b>" (incremental record deletion) +command-line options are not available. For the same reason the +"cdb" map type cannot be used to store the persistent address +verification cache for the <a href="verify.8.html">verify(8)</a> service, or to store +TLS session information for the <a href="tlsmgr.8.html">tlsmgr(8)</a> service. </p> |