codekingpro/portable-devtools

1<?xml version="1.0" encoding="UTF-8" standalone="no"?>2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>14.5. Non-Durable Settings</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="populate.html" title="14.4. Populating a Database" /><link rel="next" href="parallel-query.html" title="Chapter 15. Parallel Query" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">14.5. Non-Durable Settings</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="populate.html" title="14.4. Populating a Database">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="performance-tips.html" title="Chapter 14. Performance Tips">Up</a></td><th width="60%" align="center">Chapter 14. Performance Tips</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 16.3 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="parallel-query.html" title="Chapter 15. Parallel Query">Next</a></td></tr></table><hr /></div><div class="sect1" id="NON-DURABILITY"><div class="titlepage"><div><div><h2 class="title" style="clear: both">14.5. Non-Durable Settings <a href="#NON-DURABILITY" class="id_link">#</a></h2></div></div></div><a id="id-1.5.13.8.2" class="indexterm"></a><p>3    Durability is a database feature that guarantees the recording of4    committed transactions even if the server crashes or loses5    power.  However, durability adds significant database overhead,6    so if your site does not require such a guarantee,7    <span class="productname">PostgreSQL</span> can be configured to run8    much faster.  The following are configuration changes you can make9    to improve performance in such cases.  Except as noted below, durability10    is still guaranteed in case of a crash of the database software;11    only an abrupt operating system crash creates a risk of data loss12    or corruption when these settings are used.13 14    </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>15       Place the database cluster's data directory in a memory-backed16       file system (i.e., <acronym class="acronym">RAM</acronym> disk).  This eliminates all17       database disk I/O, but limits data storage to the amount of18       available memory (and perhaps swap).19      </p></li><li class="listitem"><p>20       Turn off <a class="xref" href="runtime-config-wal.html#GUC-FSYNC">fsync</a>;  there is no need to flush21       data to disk.22      </p></li><li class="listitem"><p>23       Turn off <a class="xref" href="runtime-config-wal.html#GUC-SYNCHRONOUS-COMMIT">synchronous_commit</a>;  there might be no24       need to force <acronym class="acronym">WAL</acronym> writes to disk on every25       commit.  This setting does risk transaction loss (though not data26       corruption) in case of a crash of the <span class="emphasis"><em>database</em></span>.27      </p></li><li class="listitem"><p>28       Turn off <a class="xref" href="runtime-config-wal.html#GUC-FULL-PAGE-WRITES">full_page_writes</a>;  there is no need29       to guard against partial page writes.30      </p></li><li class="listitem"><p>31       Increase <a class="xref" href="runtime-config-wal.html#GUC-MAX-WAL-SIZE">max_wal_size</a> and <a class="xref" href="runtime-config-wal.html#GUC-CHECKPOINT-TIMEOUT">checkpoint_timeout</a>; this reduces the frequency32       of checkpoints, but increases the storage requirements of33       <code class="filename">/pg_wal</code>.34      </p></li><li class="listitem"><p>35       Create <a class="link" href="sql-createtable.html#SQL-CREATETABLE-UNLOGGED">unlogged36       tables</a> to avoid <acronym class="acronym">WAL</acronym> writes, though it37       makes the tables non-crash-safe.38      </p></li></ul></div><p>39   </p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="populate.html" title="14.4. Populating a Database">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="performance-tips.html" title="Chapter 14. Performance Tips">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="parallel-query.html" title="Chapter 15. Parallel Query">Next</a></td></tr><tr><td width="40%" align="left" valign="top">14.4. Populating a Database </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 16.3 Documentation">Home</a></td><td width="40%" align="right" valign="top"> Chapter 15. Parallel Query</td></tr></table></div></body></html>