1#@!#!123s

: / usr / share / doc / postgresql-9.2.24 / html /
Filename : monitoring-locks.html
back
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<HTML
><HEAD
><TITLE
>Viewing Locks</TITLE
><META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK
REV="MADE"
HREF="mailto:pgsql-docs@postgresql.org"><LINK
REL="HOME"
TITLE="PostgreSQL 9.2.24 Documentation"
HREF="index.html"><LINK
REL="UP"
TITLE="Monitoring Database Activity"
HREF="monitoring.html"><LINK
REL="PREVIOUS"
TITLE="The Statistics Collector"
HREF="monitoring-stats.html"><LINK
REL="NEXT"
TITLE="Dynamic Tracing"
HREF="dynamic-trace.html"><LINK
REL="STYLESHEET"
TYPE="text/css"
HREF="stylesheet.css"><META
HTTP-EQUIV="Content-Type"
CONTENT="text/html; charset=ISO-8859-1"><META
NAME="creation"
CONTENT="2017-11-06T22:43:11"></HEAD
><BODY
CLASS="SECT1"
><DIV
CLASS="NAVHEADER"
><TABLE
SUMMARY="Header navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TH
COLSPAN="5"
ALIGN="center"
VALIGN="bottom"
><A
HREF="index.html"
>PostgreSQL 9.2.24 Documentation</A
></TH
></TR
><TR
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="top"
><A
TITLE="The Statistics Collector"
HREF="monitoring-stats.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="top"
><A
HREF="monitoring.html"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="60%"
ALIGN="center"
VALIGN="bottom"
>Chapter 27. Monitoring Database Activity</TD
><TD
WIDTH="20%"
ALIGN="right"
VALIGN="top"
><A
TITLE="Dynamic Tracing"
HREF="dynamic-trace.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><DIV
CLASS="SECT1"
><H1
CLASS="SECT1"
><A
NAME="MONITORING-LOCKS"
>27.3. Viewing Locks</A
></H1
><P
>   Another useful tool for monitoring database activity is the
   <TT
CLASS="STRUCTNAME"
>pg_locks</TT
> system table.  It allows the
   database administrator to view information about the outstanding
   locks in the lock manager. For example, this capability can be used
   to:

   <P
></P
></P><UL
><LI
><P
>      View all the locks currently outstanding, all the locks on
      relations in a particular database, all the locks on a
      particular relation, or all the locks held by a particular
      <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> session.
     </P
></LI
><LI
><P
>      Determine the relation in the current database with the most
      ungranted locks (which might be a source of contention among
      database clients).
     </P
></LI
><LI
><P
>      Determine the effect of lock contention on overall database
      performance, as well as the extent to which contention varies
      with overall database traffic.
     </P
></LI
></UL
><P>

   Details of the <TT
CLASS="STRUCTNAME"
>pg_locks</TT
> view appear in
   <A
HREF="view-pg-locks.html"
>Section 45.58</A
>.
   For more information on locking and managing concurrency with
   <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>, refer to <A
HREF="mvcc.html"
>Chapter 13</A
>.
  </P
></DIV
><DIV
CLASS="NAVFOOTER"
><HR
ALIGN="LEFT"
WIDTH="100%"><TABLE
SUMMARY="Footer navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><A
HREF="monitoring-stats.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="index.html"
ACCESSKEY="H"
>Home</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
><A
HREF="dynamic-trace.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>The Statistics Collector</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="monitoring.html"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>Dynamic Tracing</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>