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| <!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>pg_checksums</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="pgarchivecleanup.html" title="pg_archivecleanup" /><link rel="next" href="app-pgcontroldata.html" title="pg_controldata" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center"><span class="application">pg_checksums</span></th></tr><tr><td width="10%" align="left"><a accesskey="p" href="pgarchivecleanup.html" title="pg_archivecleanup">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="reference-server.html" title="PostgreSQL Server Applications">Up</a></td><th width="60%" align="center">PostgreSQL Server Applications</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="app-pgcontroldata.html" title="pg_controldata">Next</a></td></tr></table><hr /></div><div class="refentry" id="APP-PGCHECKSUMS"><div class="titlepage"></div><a id="id-1.9.5.5.1" class="indexterm"></a><div class="refnamediv"><h2><span class="refentrytitle"><span class="application">pg_checksums</span></span></h2><p>pg_checksums — enable, disable or check data checksums in a <span class="productname">PostgreSQL</span> database cluster</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="cmdsynopsis"><p id="id-1.9.5.5.4.1"><code class="command">pg_checksums</code> [<em class="replaceable"><code>option</code></em>...] [[ <code class="option">-D</code> | <code class="option">--pgdata</code> ]<em class="replaceable"><code>datadir</code></em>]</p></div></div><div class="refsect1" id="R1-APP-PGCHECKSUMS-1"><h2>Description</h2><p> |
| <span class="application">pg_checksums</span> checks, enables or disables data |
| checksums in a <span class="productname">PostgreSQL</span> cluster. The server |
| must be shut down cleanly before running |
| <span class="application">pg_checksums</span>. When verifying checksums, the exit |
| status is zero if there are no checksum errors, and nonzero if at least one |
| checksum failure is detected. When enabling or disabling checksums, the |
| exit status is nonzero if the operation failed. |
| </p><p> |
| When verifying checksums, every file in the cluster is scanned. When |
| enabling checksums, each relation file block with a changed checksum is |
| rewritten in-place. |
| Disabling checksums only updates the file <code class="filename">pg_control</code>. |
| </p></div><div class="refsect1" id="id-1.9.5.5.6"><h2>Options</h2><p> |
| The following command-line options are available: |
|
|
| </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="option">-D <em class="replaceable"><code>directory</code></em></code><br /></span><span class="term"><code class="option">--pgdata=<em class="replaceable"><code>directory</code></em></code></span></dt><dd><p> |
| Specifies the directory where the database cluster is stored. |
| </p></dd><dt><span class="term"><code class="option">-c</code><br /></span><span class="term"><code class="option">--check</code></span></dt><dd><p> |
| Checks checksums. This is the default mode if nothing else is |
| specified. |
| </p></dd><dt><span class="term"><code class="option">-d</code><br /></span><span class="term"><code class="option">--disable</code></span></dt><dd><p> |
| Disables checksums. |
| </p></dd><dt><span class="term"><code class="option">-e</code><br /></span><span class="term"><code class="option">--enable</code></span></dt><dd><p> |
| Enables checksums. |
| </p></dd><dt><span class="term"><code class="option">-f <em class="replaceable"><code>filenode</code></em></code><br /></span><span class="term"><code class="option">--filenode=<em class="replaceable"><code>filenode</code></em></code></span></dt><dd><p> |
| Only validate checksums in the relation with filenode |
| <em class="replaceable"><code>filenode</code></em>. |
| </p></dd><dt><span class="term"><code class="option">-N</code><br /></span><span class="term"><code class="option">--no-sync</code></span></dt><dd><p> |
| By default, <code class="command">pg_checksums</code> will wait for all files |
| to be written safely to disk. This option causes |
| <code class="command">pg_checksums</code> to return without waiting, which is |
| faster, but means that a subsequent operating system crash can leave |
| the updated data directory corrupt. Generally, this option is useful |
| for testing but should not be used on a production installation. |
| This option has no effect when using <code class="literal">--check</code>. |
| </p></dd><dt><span class="term"><code class="option">-P</code><br /></span><span class="term"><code class="option">--progress</code></span></dt><dd><p> |
| Enable progress reporting. Turning this on will deliver a progress |
| report while checking or enabling checksums. |
| </p></dd><dt><span class="term"><code class="option">-v</code><br /></span><span class="term"><code class="option">--verbose</code></span></dt><dd><p> |
| Enable verbose output. Lists all checked files. |
| </p></dd><dt><span class="term"><code class="option">-V</code><br /></span><span class="term"><code class="option">--version</code></span></dt><dd><p> |
| Print the <span class="application">pg_checksums</span> version and exit. |
| </p></dd><dt><span class="term"><code class="option">-?</code><br /></span><span class="term"><code class="option">--help</code></span></dt><dd><p> |
| Show help about <span class="application">pg_checksums</span> command line |
| arguments, and exit. |
| </p></dd></dl></div><p> |
| </p></div><div class="refsect1" id="id-1.9.5.5.7"><h2>Environment</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="envar">PGDATA</code></span></dt><dd><p> |
| Specifies the directory where the database cluster is |
| stored; can be overridden using the <code class="option">-D</code> option. |
| </p></dd><dt><span class="term"><code class="envar">PG_COLOR</code></span></dt><dd><p> |
| Specifies whether to use color in diagnostic messages. Possible values |
| are <code class="literal">always</code>, <code class="literal">auto</code> and |
| <code class="literal">never</code>. |
| </p></dd></dl></div></div><div class="refsect1" id="id-1.9.5.5.8"><h2>Notes</h2><p> |
| Enabling checksums in a large cluster can potentially take a long time. |
| During this operation, the cluster or other programs that write to the |
| data directory must not be started or else data loss may occur. |
| </p><p> |
| When using a replication setup with tools which perform direct copies |
| of relation file blocks (for example <a class="xref" href="app-pgrewind.html" title="pg_rewind"><span class="refentrytitle"><span class="application">pg_rewind</span></span></a>), |
| enabling or disabling checksums can lead to page corruptions in the |
| shape of incorrect checksums if the operation is not done consistently |
| across all nodes. When enabling or disabling checksums in a replication |
| setup, it is thus recommended to stop all the clusters before switching |
| them all consistently. Destroying all standbys, performing the operation |
| on the primary and finally recreating the standbys from scratch is also |
| safe. |
| </p><p> |
| If <span class="application">pg_checksums</span> is aborted or killed while |
| enabling or disabling checksums, the cluster's data checksum configuration |
| remains unchanged, and <span class="application">pg_checksums</span> can be |
| re-run to perform the same operation. |
| </p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="pgarchivecleanup.html" title="pg_archivecleanup">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="reference-server.html" title="PostgreSQL Server Applications">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="app-pgcontroldata.html" title="pg_controldata">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span class="application">pg_archivecleanup</span> </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"> <span class="application">pg_controldata</span></td></tr></table></div></body></html> |
