<!-- $Header: /cvsroot/pgsql/doc/src/sgml/wal.sgml,v 1.19 2002/09/06 20:08:06 momjian Exp $ -->

<!-- $Header: /cvsroot/pgsql/doc/src/sgml/wal.sgml,v 1.20 2002/09/06 20:26:00 momjian Exp $ -->

<chapter id="wal">

<title>Write-Ahead Logging (<acronym>WAL</acronym>)</title>

<para>

There will be at least one 16MB segment file, and will normally

not be more than <varname>CHECKPOINT_SEGMENTS</varname>)

not be more than <varname>CHECKPOINT_SEGMENTS</varname>

+ 1 files. You can use this to estimate space requirements for

WAL. Ordinarily, when old log segment files are no longer needed,

they are recycled (renamed to become the next sequential future