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Yasuhiro KIMURA
988 lines
41 KiB
HTML
988 lines
41 KiB
HTML
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml">
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
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<title>Performance Event Monitoring</title>
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<link rel="stylesheet" href="gettingStarted.css" type="text/css" />
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<meta name="generator" content="DocBook XSL Stylesheets V1.73.2" />
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<link rel="start" href="index.html" title="Berkeley DB Programmer's Reference Guide" />
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<link rel="up" href="program.html" title="Chapter 16. Programmer Notes" />
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<link rel="prev" href="program_runtime.html" title="Run-time configuration" />
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<link rel="next" href="program_faq.html" title="Programmer notes FAQ" />
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</head>
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<body>
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<div xmlns="" class="navheader">
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<div class="libver">
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<p>Library Version 18.1.40</p>
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</div>
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<table width="100%" summary="Navigation header">
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<tr>
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<th colspan="3" align="center">Performance Event
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Monitoring</th>
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</tr>
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<tr>
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<td width="20%" align="left"><a accesskey="p" href="program_runtime.html">Prev</a> </td>
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<th width="60%" align="center">Chapter 16. Programmer Notes </th>
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<td width="20%" align="right"> <a accesskey="n" href="program_faq.html">Next</a></td>
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</tr>
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</table>
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<hr />
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</div>
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<div class="sect1" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h2 class="title" style="clear: both"><a id="program_perfmon"></a>Performance Event
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Monitoring</h2>
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</div>
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</div>
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</div>
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<div class="toc">
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<dl>
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<dt>
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<span class="sect2">
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<a href="program_perfmon.html#program_perfmon_dtrace">Using the DTrace Provider</a>
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</span>
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</dt>
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<dt>
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<span class="sect2">
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<a href="program_perfmon.html#program_perfmon_stap">Using SystemTap</a>
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</span>
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</dt>
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<dt>
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<span class="sect2">
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<a href="program_perfmon.html#program_perfmon_examples">Example
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Scripts</a>
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</span>
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</dt>
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<dt>
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<span class="sect2">
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<a href="program_perfmon.html#program_perfmon_probes">Performance Events Reference</a>
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</span>
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</dt>
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</dl>
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</div>
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<p>
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The Performance Event Monitoring feature uses Solaris
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DTrace or Linux SystemTap to "publish" interesting events as
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they occur inside of Berkeley DB. The operating system
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utilities <span class="command"><strong>dtrace</strong></span> or <span class="command"><strong>stap</strong></span>
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run scripts which select, analyze, and display events. There
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is no need to modify the application. Any application which
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uses that Berkeley DB library can be monitored. For more
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||
information about these instrumentation tools refer to the
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following pages:
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||
</p>
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<div class="variablelist">
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<dl>
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<dt>
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<span class="term">DTrace</span>
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</dt>
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<dd>
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<a class="ulink" href="http://www.oracle.com/technetwork/server-storage/solaris11/technologies/dtrace-1930301.html" target="_top">http://www.oracle.com/technetwork/server-storage/solaris11/technologies/dtrace-1930301.html</a>
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</dd>
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<dt>
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<span class="term">SystemTap</span>
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</dt>
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<dd>
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<a class="ulink" href="http://sourceware.org/systemtap/" target="_top">http://sourceware.org/systemtap/</a>
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</dd>
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||
</dl>
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</div>
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||
<p>
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||
</p>
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||
<p>
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||
Performance Event Monitoring is available for operating
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||
systems where DTrace or SystemTap supports static probe points
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in user applications, such as Solaris 10 and OpenSolaris, some
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||
versions of Linux, and Mac OS X 10.6 and later. By including
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--enable-dtrace to the configuration options, the resulting
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libraries will include probe points for these event
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||
categories:
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</p>
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<div class="itemizedlist">
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<ul type="disc">
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<li>
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database operations: opening a database or
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cursor, get, put, delete.
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</li>
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<li>
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||
internal operations regarding disk allocation,
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transactions, concurrency control, and caching.
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</li>
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<li>
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the beginning and ending of waiting periods due
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to conflicting transactional consistency locks (for
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example, page locks), mutexes, or shared latches.
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</li>
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||
<li>
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timing dependent code paths which are expected
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to be infrequent. These could raise concerns if they
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were to happen too often.
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</li>
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</ul>
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||
</div>
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||
<p>
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||
These probe points are implemented as
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user-level statically defined traces (USDT's) for DTrace, and
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static userspace markers for SystemTap.
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</p>
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<p>
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To monitor the statistics values as they are updated
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include the --enable-perfmon-statistics configuration option.
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This option generates probe points for updates to many of the
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counters whose values are displayed by the db_stat utility or
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returned by the various statistics functions. The "cache"
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example script uses a few of these probe points.
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</p>
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<p>
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Performance Event Monitoring is intended to be suitable for
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||
production applications. Running Berkeley DB with DTrace or
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SystemTap support built in has little effect on execution
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speed until probes are enabled at runtime by the
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<span class="command"><strong>dtrace</strong></span> or <span class="command"><strong>stap</strong></span>
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programs.
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</p>
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||
<p>
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||
The list of available events may be displayed by running
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'make listprobes' after building the libdb-18.1
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shared library.
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</p>
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<div class="sect2" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h3 class="title"><a id="program_perfmon_dtrace"></a>Using the DTrace Provider</h3>
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</div>
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</div>
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</div>
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<p>
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The DTrace probe provider for Berkeley DB is named
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'bdb'. A simple dtrace command to monitor all
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dtrace-enabled Berkeley DB activity in the system is:
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</p>
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||
<p>
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<code class="code"> dtrace -Zn 'bdb*::: { printf("%s", probename); }'
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</code>
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</p>
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<p>
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DTrace requires elevated privileges in order to run. On
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Solaris you can avoid running as root by giving any users
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who need to run <span class="command"><strong>dtrace</strong></span> the dtrace_proc
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or dtrace_user privilege in
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<span class="command"><strong>/etc/user_attr</strong></span>.
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</p>
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<p>
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DTrace works on both 32 and 64 bit applications.
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However, when tracing a 32-bit application on a 64-bit
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processor it might be necessary to pass a "32 bit" option
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to <span class="command"><strong>dtrace</strong></span>. Without this option the D
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language might use a pointer size of 8 bytes, which could
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cause pointer values (and structures containing them) to
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be processed incorrectly. Use the <code class="code">-32</code> option
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on Solaris; on Mac OS X use <code class="code">-arch i386</code>.
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</p>
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</div>
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<div class="sect2" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h3 class="title"><a id="program_perfmon_stap"></a>Using SystemTap</h3>
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</div>
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</div>
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</div>
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<p>
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SystemTap looks up its static userspace markers in the
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library name specified in the <span class="command"><strong>stap</strong></span>
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script. A simple <span class="command"><strong>stap</strong></span> command to list
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the probes of the default Berkeley DB installation is:
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</p>
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<p>
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<code class="code"> stap -l 'process("/usr/local/BerkeleyDB.18.1/lib/libdb-18.1.so").mark("*")'
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</code>
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</p>
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<p>
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Berkeley DB supports SystemTap version 1.1 or later.
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Building with userspace marker support requires
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<code class="filename">sys/sdt.h</code>, which is often
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available in the package
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<code class="filename">systemtap-sdt-devel</code>. Running
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<span class="command"><strong>stap</strong></span> with userspace markers
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requires that the kernel have "utrace" support; see <a class="ulink" href="http://sourceware.org/systemtap/wiki/utrace" target="_top">http://sourceware.org/systemtap/wiki/utrace</a>
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for more information.
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</p>
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<p>
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SystemTap needs elevated privileges in order to run.
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You can avoid running as root by adding the users who need
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to run <span class="command"><strong>stap</strong></span> to the group stapdev.
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</p>
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</div>
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<div class="sect2" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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||
<h3 class="title"><a id="program_perfmon_examples"></a>Example
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Scripts</h3>
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||
</div>
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||
</div>
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||
</div>
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<p>
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Berkeley DB includes several example scripts, in both
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DTrace and SystemTap versions. The DTrace examples end
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with a <code class="filename">.d</code> suffix and are located in
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<code class="filename">util/dtrace</code>. The SystemTap
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examples have a <code class="filename">.stp</code> suffix and can
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found be in <code class="filename">util/systemtap</code>. The
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Berkeley DB shared library name, including any necessary
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path, is expected as the first parameter to the SystemTap
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examples.
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</p>
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<div class="variablelist">
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<dl>
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<dt>
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<span class="term">apicalls</span>
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</dt>
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<dd>
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This script graphs the count of the
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main API calls. The result is grouped by
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thread of the target process.
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</dd>
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<dt>
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<span class="term">apitimes</span>
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</dt>
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<dd>
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This script graphs the time spent in
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the main API calls, grouped by thread.
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</dd>
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<dt>
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<span class="term"> apitrace </span>
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</dt>
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<dd>
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This script displays the entry to and
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return from each of the main API calls.
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</dd>
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<dt>
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<span class="term"> cache </span>
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</dt>
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<dd>
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This script displays overall and
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per-file buffer cache statistics every
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<span class="emphasis"><em>N</em></span> (default: 1)
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seconds for <span class="emphasis"><em>M</em></span> (default:
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60) intervals. It prints the number of cache
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hits, misses, and evictions for each file with
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any activity during the interval.
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</dd>
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<dt>
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||
<span class="term"> dbdefs</span>
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||
</dt>
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||
<dd>
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||
This contains DTrace-compatible
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||
declarations of Berkeley DB data structures
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returned from probe points. There is no Linux
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||
equivalent; SystemTap can obtain type
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information directly from the debugging
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symbols compiled into the
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libdb*-18.1.so shared library.
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</dd>
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<dt>
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<span class="term"> locktimes </span>
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</dt>
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<dd>
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This script graphs the time spent
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waiting for DB page locks. The result times in
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nanoseconds are grouped by filename, pgno, and
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lock_mode. The optional integer maxcount
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parameter directs the script to exit once that
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many page lock waits have been measured.
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</dd>
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<dt>
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<span class="term"> locktimesid </span>
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||
</dt>
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<dd>
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This is similar to the locktimes script
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above, except that it displays the 20 byte
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file identifier rather than the file name.
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This can be useful when there are several
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environments involved, or when database files
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are recreated during the monitoring period.
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</dd>
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<dt>
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<span class="term"> mutex </span>
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</dt>
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<dd>
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This script measures mutex wait
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periods, summarizing the results two ways.
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<div class="itemizedlist"><ul type="disc"><li>
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The first grouping is by mutex,
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mode (exclusive or shared), and thread
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id.
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</li><li>
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The second grouping is by the
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mutex category and mode (exclusive or
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shared). The mutex categories are the
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MTX_XXX definitions in
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<code class="filename">dbinc/mutex.h</code>.
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</li></ul></div></dd>
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<dt>
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<span class="term"> showerror </span>
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</dt>
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<dd>
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This script displays the application
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stack when the basic error routines are
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called. It provides additional information
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about an error, beyond the string sent to the
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diagnostic output.
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</dd>
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</dl>
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</div>
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<p>
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</p>
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<p>
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These examples are designed to trace a single process.
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They run until interrupted, or the monitored process
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exits, or the limit as given in an optional 'maximum
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count' argument has been reached.
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</p>
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||
</div>
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||
<div class="sect2" lang="en" xml:lang="en">
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||
<div class="titlepage">
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||
<div>
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||
<div>
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||
<h3 class="title"><a id="program_perfmon_probes"></a>Performance Events Reference</h3>
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||
</div>
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||
</div>
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||
</div>
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||
<p>
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||
The events are described below as if they were
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||
functions with ANSI C-style signatures. The values each
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||
event provides to DTrace or SystemTap are the arguments to
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the functions.
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||
</p>
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||
<p>
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</p>
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||
<div class="variablelist">
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||
<dl>
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||
<dt>
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<span class="term"> alloc </span>
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||
</dt>
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<dd>
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<p>
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The alloc class covers the allocation of "on disk"
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||
database pages.
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||
</p>
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<div class="variablelist">
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||
<dl>
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||
<dt>
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<span class="term">alloc-new (char *file, char *db, unsigned
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pgno, unsigned type, struct _db_page *pg, int
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ret); </span>
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||
</dt>
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||
<dd>
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An attempt to allocate a database page
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||
of type 'type' for database 'db' returned
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'ret'. If the allocation succeeded then ret is
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0, pgno is the location of the new page, and
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pg is the address of the new page. Details of
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the page can be extracted from the pg pointer.
|
||
</dd>
|
||
<dt>
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<span class="term"> alloc-free (char *file, char *db, unsigned
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pgno, unsigned ret); </span>
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||
</dt>
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<dd>
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An attempt to free the page 'pgno' of
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'db' returned 'ret'. When successful the page
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is returned to the free list or the file is
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truncated.
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||
</dd>
|
||
<dt>
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||
<span class="term">alloc-btree_split (char *file, char *db,
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unsigned pgno, unsigned parent, unsigned
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||
level); </span>
|
||
</dt>
|
||
<dd>
|
||
A btree split of pgno in db is being
|
||
attempted. The parent page number and the
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||
level in the btree are also provided.
|
||
</dd>
|
||
</dl>
|
||
</div>
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> db </span>
|
||
</dt>
|
||
<dd>
|
||
<p>
|
||
These DB API calls provide the name of the file and
|
||
database being accessed. In-memory databases will have
|
||
a NULL (0) file name address. The db name will be null
|
||
unless subdatabases are in use.
|
||
</p>
|
||
<div class="variablelist">
|
||
<dl>
|
||
<dt>
|
||
<span class="term"> db-open (char *file, char *db, unsigned
|
||
flags, uint8_t *fileid); </span>
|
||
</dt>
|
||
<dd>
|
||
The database or file name was opened.
|
||
The 20 byte unique fileid can be used to keep
|
||
track of databases as they are created and
|
||
destroyed.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> db-close (char *file, char *db, unsigned
|
||
flags, uint8_t *fileid); </span>
|
||
</dt>
|
||
<dd>
|
||
The database or file name was closed.
|
||
</dd>
|
||
<dt>
|
||
<span class="term">db-cursor (char *file, char *db, unsigned
|
||
txnid, unsigned flags, uint8_t *fileid); </span>
|
||
</dt>
|
||
<dd>
|
||
An attempt is being made to open a
|
||
cursor on the database or file.
|
||
</dd>
|
||
<dt>
|
||
<span class="term">db-get (char *file, char *db, unsigned
|
||
txnid, DBT *key, DBT *data, unsigned flags); </span>
|
||
</dt>
|
||
<dd>
|
||
An attempt is being made to get data
|
||
from a db.
|
||
</dd>
|
||
<dt>
|
||
<span class="term">db-put (char *file, char *db, unsigned
|
||
txnid, DBT *key, DBT *data, unsigned flags); </span>
|
||
</dt>
|
||
<dd>
|
||
An attempt is being made to put data to
|
||
a db.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> db-del (char *file, char *db, unsigned
|
||
txnid, DBT *key, unsigned flags); </span>
|
||
</dt>
|
||
<dd>
|
||
An attempt is being made to delete data
|
||
from a db.
|
||
</dd>
|
||
</dl>
|
||
</div>
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> lock </span>
|
||
</dt>
|
||
<dd>
|
||
<p>
|
||
The lock class monitors the transactional
|
||
consistency locks: page, record, and database. It also
|
||
monitors the non-transactional file handle locks.
|
||
</p>
|
||
<div class="variablelist">
|
||
<dl>
|
||
<dt>
|
||
<span class="term"> lock-suspend (DBT *lock, db_lockmode_t
|
||
lock_mode); </span>
|
||
</dt>
|
||
<dd>
|
||
The thread is about to suspend itself
|
||
because another locker already has a
|
||
conflicting lock on object 'lock'. The lock
|
||
DBT's data points to a __db_ilock structure,
|
||
except for the atypical program which uses
|
||
application specific locking.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> lock-resume (DBT *lock, db_lockmode_t
|
||
lock_mode); </span>
|
||
</dt>
|
||
<dd>
|
||
The thread is awakening from a suspend.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> lock-put (struct __sh_dbt *lock, unsigned
|
||
flags); </span>
|
||
</dt>
|
||
<dd>
|
||
The lock is being freed.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> lock-put_reduce_count (struct __sh_dbt
|
||
*lock, unsigned flags); </span>
|
||
</dt>
|
||
<dd>
|
||
The lock would have been freed except
|
||
that its refcount was greater than 1.
|
||
</dd>
|
||
</dl>
|
||
</div>
|
||
<p>
|
||
These lock counters are included by
|
||
--enable-perfmon-statistics.
|
||
</p>
|
||
<div class="variablelist">
|
||
<dl>
|
||
<dt>
|
||
<span class="term">lock-deadlock (unsigned st_ndeadlocks,
|
||
unsigned locker_id, struct __sh_dbt
|
||
*lock_obj); </span>
|
||
</dt>
|
||
<dd>
|
||
The locker_id's lock request in
|
||
lock_obj is about to be aborted in order to
|
||
resolve a deadlock. The lock region's
|
||
st_ndeadlocks has been incremented.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> lock-nowait_notgranted (unsigned count, DBT
|
||
*lock, unsigned locker_id); </span>
|
||
</dt>
|
||
<dd>
|
||
A DB_LOCK_NOWAIT lock request by
|
||
locker_id would have had to wait. The lock
|
||
regions's st_lock_nowait has been incremented
|
||
and the request returns DB_LOCK_NOTGRANTED.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> lock-steal (unsigned st_locksteals,
|
||
unsigned from, unsigned to); </span>
|
||
</dt>
|
||
<dd>
|
||
A lock is being stolen from one
|
||
partition for another one. The 'from' lock
|
||
partition's st_locksteals has been
|
||
incremented.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> lock-object_steal (unsigned
|
||
st_objectsteals, unsigned from, unsigned to); </span>
|
||
</dt>
|
||
<dd>
|
||
A lock object is being stolen from one
|
||
partition for another one. The 'from' lock
|
||
partition's st_objectsteals has been
|
||
incremented.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> lock-locktimeout (unsigned
|
||
st_nlocktimeouts, const DBT *lock); </span>
|
||
</dt>
|
||
<dd>
|
||
A lock wait expired due to the lock
|
||
request timeout.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> lock-txntimeout (unsigned st_ntxntimeouts,
|
||
const DBT *lock); </span>
|
||
</dt>
|
||
<dd>
|
||
A lock wait expired due to the
|
||
transaction's timeout.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> lock-nlockers (unsigned active, unsigned
|
||
locker_id); </span>
|
||
</dt>
|
||
<dd> The allocation or deallocation of the
|
||
locker id changed the number of active locker
|
||
identifiers. </dd>
|
||
<dt>
|
||
<span class="term"> lock-maxnlockers (unsigned new_max_active,
|
||
unsigned locker_id); </span>
|
||
</dt>
|
||
<dd>
|
||
The allocation of the locker id set a
|
||
new maximum number of active locker
|
||
identifiers.
|
||
</dd>
|
||
</dl>
|
||
</div>
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> mpool </span>
|
||
</dt>
|
||
<dd>
|
||
<p>
|
||
The mpool class monitors the allocation and
|
||
management of memory, including the cache.
|
||
</p>
|
||
<div class="variablelist">
|
||
<dl>
|
||
<dt>
|
||
<span class="term"> mpool-read (char *file, unsigned pgno,
|
||
struct __bh *buf); </span>
|
||
</dt>
|
||
<dd>
|
||
Read a page from file into buf.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> mpool-write (char *file, unsigned pgno,
|
||
struct __bh *buf); </span>
|
||
</dt>
|
||
<dd>
|
||
Write a page from buf to file.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> mpool-env_alloc (unsigned size, unsigned
|
||
region_id, unsigned reg_type); </span>
|
||
</dt>
|
||
<dd>
|
||
This is an attempt to allocate size
|
||
bytes from region_id. The reg_type is one of
|
||
the reg_type_t enum values.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> mpool-evict (char *file, unsigned pgno,
|
||
struct __bh *buf); </span>
|
||
</dt>
|
||
<dd>
|
||
The page is about to be removed from
|
||
the cache.
|
||
</dd>
|
||
<dt>
|
||
<span class="term">mpool-alloc_wrap (unsigned alloc_len, int
|
||
region_id, int wrap_count, int put_counter); </span>
|
||
</dt>
|
||
<dd>
|
||
The memory allocator has incremented
|
||
wrap_count after searching through the entire
|
||
region without being able to fulfill the
|
||
request for alloc_len bytes. As wrap_count
|
||
increases the library makes more effort to
|
||
allocate space.
|
||
</dd>
|
||
</dl>
|
||
</div>
|
||
<p>
|
||
These mpool counters are included by
|
||
--enable-perfmon-statistics.
|
||
</p>
|
||
<div class="variablelist">
|
||
<dl>
|
||
<dt>
|
||
<span class="term"> mpool-clean_eviction (unsigned st_ro_evict,
|
||
unsigned region_id); </span>
|
||
</dt>
|
||
<dd>
|
||
The eviction of a clean page from a
|
||
cache incremented st_ro_evict.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> mpool-dirty_eviction (unsigned st_rw_evict,
|
||
unsigned region_id); </span>
|
||
</dt>
|
||
<dd>
|
||
The eviction of a dirty page from a
|
||
cache incremented st_rw_evict. The page has
|
||
already been written out.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> mpool-fail (unsigned failure_count,
|
||
unsigned alloc_len, unsigned region_id); </span>
|
||
</dt>
|
||
<dd>
|
||
An attempt to allocate memory from
|
||
region_id failed.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> mpool-hash_search (unsigned
|
||
st_hash_searches, char *file, unsigned pgno); </span>
|
||
</dt>
|
||
<dd>
|
||
A search for pgno of file incremented
|
||
st_hash_searches. </dd>
|
||
<dt>
|
||
<span class="term"> mpool-hash_examined (unsigned
|
||
st_hash_examined, char *file, unsigned pgno); </span>
|
||
</dt>
|
||
<dd>
|
||
A search for pgno of file increased
|
||
st_hash_examined by the number of hash buckets
|
||
examined.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> mpool-hash_longest (unsigned
|
||
st_hash_longest, char *file, unsigned pgno); </span>
|
||
</dt>
|
||
<dd>
|
||
A search for pgno of file set a new
|
||
maximum st_hash_longest value.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> mpool-map (unsigned st_map, char *file,
|
||
unsigned pgno); </span>
|
||
</dt>
|
||
<dd>
|
||
A file's st_map count was incremented
|
||
after a page was mapped into memory. The
|
||
mapping might have caused disk I/O.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> mpool-hit (unsigned st_cache_hit, char
|
||
*file, unsigned pgno); </span>
|
||
</dt>
|
||
<dd>
|
||
The hit count was incremented because
|
||
pgno from file was found in the cache.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> mpool-miss (unsigned st_cache_miss, char
|
||
*file, unsigned pgno); </span>
|
||
</dt>
|
||
<dd>
|
||
The miss count was incremented because
|
||
pgno from file was not already present in the
|
||
cache.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> mpool-page_create (unsigned st_page_create,
|
||
char *file, unsigned pgno); </span>
|
||
</dt>
|
||
<dd>
|
||
The st_page_create field was
|
||
incremented because the pgno of file was
|
||
created in the cache.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> mpool-page_in (unsigned st_page_in, char
|
||
*file, unsigned pgno); </span>
|
||
</dt>
|
||
<dd>
|
||
The st_page_in field was incremented
|
||
because the pgno from file was read into the
|
||
cache.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> mpool-page_out (unsigned st_page_out, char
|
||
*file, unsigned pgno); </span>
|
||
</dt>
|
||
<dd>
|
||
The st_page_out field was incremented
|
||
because the pgno from file was written out.
|
||
</dd>
|
||
</dl>
|
||
</div>
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> mutex </span>
|
||
</dt>
|
||
<dd>
|
||
<p>
|
||
The mutex category monitors includes shared
|
||
latches. The alloc_id value is one of the MTX_XXX
|
||
definitions from dbinc/mutex.h
|
||
</p>
|
||
<div class="variablelist">
|
||
<dl>
|
||
<dt>
|
||
<span class="term">mutex-suspend (unsigned mutex, unsigned
|
||
excl, unsigned alloc_id, struct __db_mutex_t
|
||
*mutexp); </span>
|
||
</dt>
|
||
<dd>
|
||
This thread is about to suspend itself
|
||
because a thread has the mutex or shared latch
|
||
locked in a mode which conflicts with the this
|
||
request.
|
||
</dd>
|
||
<dt>
|
||
<span class="term">mutex-resume (unsigned mutex, unsigned excl,
|
||
unsigned alloc_id, struct __db_mutex_t
|
||
*mutexp); </span>
|
||
</dt>
|
||
<dd>
|
||
The thread is returning from a suspend
|
||
and will attempt to obtain the mutex or shared
|
||
latch again. It might need to suspend again.
|
||
</dd>
|
||
</dl>
|
||
</div>
|
||
<p>
|
||
These mutex counters are included by
|
||
--enable-perfmon-statistics.
|
||
</p>
|
||
<div class="variablelist">
|
||
<dl>
|
||
<dt>
|
||
<span class="term"> mutex-set_nowait (unsigned
|
||
mutex_set_nowait, unsigned mutex); </span>
|
||
</dt>
|
||
<dd>
|
||
Increment the count of times that the
|
||
mutex was free when trying to lock it.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> mutex-set_wait (unsigned mutex_set_wait,
|
||
unsigned mutex); </span>
|
||
</dt>
|
||
<dd>
|
||
Increment the count of times that the
|
||
mutex was busy when trying to lock it.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> mutex-set_rd_nowait (unsigned
|
||
mutex_set_rd_nowait, unsigned mutex); </span>
|
||
</dt>
|
||
<dd>
|
||
Increment the count of times that the
|
||
shared latch was free when trying to get a
|
||
shared lock on it.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> mutex-set_rd_wait (unsigned
|
||
mutex_set_rd_wait, unsigned mutex); </span>
|
||
</dt>
|
||
<dd>
|
||
Increment the count of times that the
|
||
shared latch was already exclusively latched
|
||
when trying to get a shared lock on it.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> mutex-hybrid_wait (unsigned hybrid_wait,
|
||
unsigned mutex); </span>
|
||
</dt>
|
||
<dd>
|
||
Increment the count of times that a
|
||
hybrid mutex had to block on its condition
|
||
variable. n a busy system this might happen
|
||
several times before the corresponding
|
||
hybrid_wakeup.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> mutex-hybrid_wakeup (unsigned
|
||
hybrid_wakeup, unsigned mutex); </span>
|
||
</dt>
|
||
<dd>
|
||
Increment the count of times that a
|
||
hybrid mutex finished one or more waits for
|
||
its condition variable.
|
||
</dd>
|
||
</dl>
|
||
</div>
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> txn </span>
|
||
</dt>
|
||
<dd>
|
||
<p>
|
||
The txn category covers the basic transaction
|
||
operations.
|
||
</p>
|
||
<div class="variablelist">
|
||
<dl>
|
||
<dt>
|
||
<span class="term"> txn-begin (unsigned txnid, unsigned flags); </span>
|
||
</dt>
|
||
<dd>
|
||
A transaction was successfully begun.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> txn-commit (unsigned txnid, unsigned
|
||
flags); </span>
|
||
</dt>
|
||
<dd>
|
||
A transaction is starting to commit.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> txn-prepare (unsigned txnid, uint8_t *gid); </span>
|
||
</dt>
|
||
<dd>
|
||
The transaction is starting to prepare,
|
||
flushing the log so that a future commit can
|
||
be guaranteed to succeed. The global
|
||
identifier field is 128 bytes long.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> txn-abort (unsigned txnid); </span>
|
||
</dt>
|
||
<dd>
|
||
The transaction is about to abort.
|
||
</dd>
|
||
</dl>
|
||
</div>
|
||
<p>
|
||
These txn counters are included by
|
||
--enable-perfmon-statistics.
|
||
</p>
|
||
<div class="variablelist">
|
||
<dl>
|
||
<dt>
|
||
<span class="term"> txn-nbegins (unsigned st_nbegins, unsigned
|
||
txnid); </span>
|
||
</dt>
|
||
<dd>
|
||
Beginning the transaction incremented
|
||
st_nbegins.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> txn-naborts (unsigned st_nbegins, unsigned
|
||
txnid); </span>
|
||
</dt>
|
||
<dd>
|
||
Aborting the transaction incremented
|
||
st_naborts.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> txn-ncommits (unsigned st_ncommits,
|
||
unsigned txnid); </span>
|
||
</dt>
|
||
<dd>
|
||
Committing the transaction incremented
|
||
st_ncommits.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> txn-nactive (unsigned st_nactive, unsigned
|
||
txnid); </span>
|
||
</dt>
|
||
<dd>
|
||
Beginning or ending the transaction
|
||
updated the number of active transactions.
|
||
</dd>
|
||
<dt>
|
||
<span class="term"> txn-maxnactive (unsigned st_maxnactive,
|
||
unsigned txnid); </span>
|
||
</dt>
|
||
<dd>
|
||
The creation of the transaction set a
|
||
new maximum number of active transactions.
|
||
</dd>
|
||
</dl>
|
||
</div>
|
||
</dd>
|
||
</dl>
|
||
</div>
|
||
<p>
|
||
</p>
|
||
</div>
|
||
</div>
|
||
<div class="navfooter">
|
||
<hr />
|
||
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|
||
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|
||
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|
||
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|
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|
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|
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|
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