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>28.3. Viewing Locks</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="monitoring-stats.html" title="28.2. The Cumulative Statistics System" /><link rel="next" href="progress-reporting.html" title="28.4. Progress Reporting" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">28.3. Viewing Locks</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="monitoring-stats.html" title="28.2. The Cumulative Statistics System">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="monitoring.html" title="Chapter 28. Monitoring Database Activity">Up</a></td><th width="60%" align="center">Chapter 28. Monitoring Database Activity</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="progress-reporting.html" title="28.4. Progress Reporting">Next</a></td></tr></table><hr /></div><div class="sect1" id="MONITORING-LOCKS"><div class="titlepage"><div><div><h2 class="title" style="clear: both">28.3. Viewing Locks <a href="#MONITORING-LOCKS" class="id_link">#</a></h2></div></div></div><a id="id-1.6.15.8.2" class="indexterm"></a><p>3   Another useful tool for monitoring database activity is the4   <code class="structname">pg_locks</code> system table.  It allows the5   database administrator to view information about the outstanding6   locks in the lock manager. For example, this capability can be used7   to:8 9   </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>10      View all the locks currently outstanding, all the locks on11      relations in a particular database, all the locks on a12      particular relation, or all the locks held by a particular13      <span class="productname">PostgreSQL</span> session.14     </p></li><li class="listitem"><p>15      Determine the relation in the current database with the most16      ungranted locks (which might be a source of contention among17      database clients).18     </p></li><li class="listitem"><p>19      Determine the effect of lock contention on overall database20      performance, as well as the extent to which contention varies21      with overall database traffic.22     </p></li></ul></div><p>23 24   Details of the <code class="structname">pg_locks</code> view appear in25   <a class="xref" href="view-pg-locks.html" title="54.12. pg_locks">Section 54.12</a>.26   For more information on locking and managing concurrency with27   <span class="productname">PostgreSQL</span>, refer to <a class="xref" href="mvcc.html" title="Chapter 13. Concurrency Control">Chapter 13</a>.28  </p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="monitoring-stats.html" title="28.2. The Cumulative Statistics System">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="monitoring.html" title="Chapter 28. Monitoring Database Activity">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="progress-reporting.html" title="28.4. Progress Reporting">Next</a></td></tr><tr><td width="40%" align="left" valign="top">28.2. The Cumulative Statistics System </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"> 28.4. Progress Reporting</td></tr></table></div></body></html>