<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >Monitoring Database Activity</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 8.4.8 Documentation" HREF="index.html"><LINK REL="UP" TITLE="Server Administration" HREF="admin.html"><LINK REL="PREVIOUS" TITLE="High Availability, Load Balancing, and Replication" HREF="high-availability.html"><LINK REL="NEXT" TITLE="Standard Unix Tools" HREF="monitoring-ps.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="2011-04-15T03:27:09"></HEAD ><BODY CLASS="CHAPTER" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="5" ALIGN="center" VALIGN="bottom" >PostgreSQL 8.4.8 Documentation</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="high-availability.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="high-availability.html" >Fast Backward</A ></TD ><TD WIDTH="60%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="top" ><A HREF="diskusage.html" >Fast Forward</A ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="top" ><A HREF="monitoring-ps.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="CHAPTER" ><H1 ><A NAME="MONITORING" ></A >Chapter 26. Monitoring Database Activity</H1 ><DIV CLASS="TOC" ><DL ><DT ><B >Table of Contents</B ></DT ><DT >26.1. <A HREF="monitoring-ps.html" >Standard Unix Tools</A ></DT ><DT >26.2. <A HREF="monitoring-stats.html" >The Statistics Collector</A ></DT ><DD ><DL ><DT >26.2.1. <A HREF="monitoring-stats.html#MONITORING-STATS-SETUP" >Statistics Collection Configuration</A ></DT ><DT >26.2.2. <A HREF="monitoring-stats.html#MONITORING-STATS-VIEWS" >Viewing Collected Statistics</A ></DT ></DL ></DD ><DT >26.3. <A HREF="monitoring-locks.html" >Viewing Locks</A ></DT ><DT >26.4. <A HREF="dynamic-trace.html" >Dynamic Tracing</A ></DT ><DD ><DL ><DT >26.4.1. <A HREF="dynamic-trace.html#COMPILING-FOR-TRACE" >Compiling for Dynamic Tracing</A ></DT ><DT >26.4.2. <A HREF="dynamic-trace.html#TRACE-POINTS" >Built-in Probes</A ></DT ><DT >26.4.3. <A HREF="dynamic-trace.html#USING-TRACE-POINTS" >Using Probes</A ></DT ><DT >26.4.4. <A HREF="dynamic-trace.html#DEFINING-TRACE-POINTS" >Defining New Probes</A ></DT ></DL ></DD ></DL ></DIV ><A NAME="AEN31472" ></A ><A NAME="AEN31475" ></A ><P > A database administrator frequently wonders, <SPAN CLASS="QUOTE" >"What is the system doing right now?"</SPAN > This chapter discusses how to find that out. </P ><P > Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN >'s statistics collector, but one should not neglect regular Unix monitoring programs such as <TT CLASS="COMMAND" >ps</TT >, <TT CLASS="COMMAND" >top</TT >, <TT CLASS="COMMAND" >iostat</TT >, and <TT CLASS="COMMAND" >vmstat</TT >. Also, once one has identified a poorly-performing query, further investigation might be needed using <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN >'s <A HREF="sql-explain.html" ><I >EXPLAIN</I ></A > command. <A HREF="using-explain.html" >Section 14.1</A > discusses <TT CLASS="COMMAND" >EXPLAIN</TT > and other methods for understanding the behavior of an individual query. </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="high-availability.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="monitoring-ps.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >High Availability, Load Balancing, and Replication</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="admin.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Standard Unix Tools</TD ></TR ></TABLE ></DIV ></BODY ></HTML >