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diff --git a/doc/src/sgml/html/non-durability.html b/doc/src/sgml/html/non-durability.html new file mode 100644 index 0000000..d219821 --- /dev/null +++ b/doc/src/sgml/html/non-durability.html @@ -0,0 +1,39 @@ +<?xml version="1.0" encoding="UTF-8" standalone="no"?> +<!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 15.4 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</h2></div></div></div><a id="id-1.5.13.8.2" class="indexterm"></a><p> + Durability is a database feature that guarantees the recording of + committed transactions even if the server crashes or loses + power. However, durability adds significant database overhead, + so if your site does not require such a guarantee, + <span class="productname">PostgreSQL</span> can be configured to run + much faster. The following are configuration changes you can make + to improve performance in such cases. Except as noted below, durability + is still guaranteed in case of a crash of the database software; + only an abrupt operating system crash creates a risk of data loss + or corruption when these settings are used. + + </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p> + Place the database cluster's data directory in a memory-backed + file system (i.e., <acronym class="acronym">RAM</acronym> disk). This eliminates all + database disk I/O, but limits data storage to the amount of + available memory (and perhaps swap). + </p></li><li class="listitem"><p> + Turn off <a class="xref" href="runtime-config-wal.html#GUC-FSYNC">fsync</a>; there is no need to flush + data to disk. + </p></li><li class="listitem"><p> + Turn off <a class="xref" href="runtime-config-wal.html#GUC-SYNCHRONOUS-COMMIT">synchronous_commit</a>; there might be no + need to force <acronym class="acronym">WAL</acronym> writes to disk on every + commit. This setting does risk transaction loss (though not data + corruption) in case of a crash of the <span class="emphasis"><em>database</em></span>. + </p></li><li class="listitem"><p> + Turn off <a class="xref" href="runtime-config-wal.html#GUC-FULL-PAGE-WRITES">full_page_writes</a>; there is no need + to guard against partial page writes. + </p></li><li class="listitem"><p> + 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 frequency + of checkpoints, but increases the storage requirements of + <code class="filename">/pg_wal</code>. + </p></li><li class="listitem"><p> + Create <a class="link" href="sql-createtable.html#SQL-CREATETABLE-UNLOGGED">unlogged + tables</a> to avoid <acronym class="acronym">WAL</acronym> writes, though it + makes the tables non-crash-safe. + </p></li></ul></div><p> + </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 15.4 Documentation">Home</a></td><td width="40%" align="right" valign="top"> Chapter 15. Parallel Query</td></tr></table></div></body></html>
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