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Add GUC log_lock_waits to log long wait times.

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Simon Riggs
This commit is contained in:
Bruce Momjian
2007-03-03 18:46:40 +00:00
parent f52019cf80
commit e52c4a6e26
7 changed files with 122 additions and 61 deletions
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26
doc/src/sgml/config.sgml
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@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.113 2007/03/02 23:37:22 tgl Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.114 2007/03/03 18:46:40 momjian Exp $ -->
<chapter Id="runtime-config">
<title>Server Configuration</title>
@ -2946,6 +2946,21 @@ SELECT * FROM parent WHERE key = 2400;
</listitem>
</varlistentry>
<varlistentry id="guc-log-lock-waits" xreflabel="log_lock_waits">
<term><varname>log_lock_waits</varname> (<type>boolean</type>)</term>
<indexterm>
<primary><varname>log_lock_waits</> configuration parameter</primary>
</indexterm>
<listitem>
<para>
Controls whether a log message is produced when a statement waits
longer than <xref linkend="guc-deadlock-timeout"> to acquire a
lock. This is useful in determining if lock waits are causing
poor performance. The default is <literal>off</>.
</para>
</listitem>
</varlistentry>
<varlistentry id="guc-log-temp-files" xreflabel="log_temp_files">
<term><varname>log_temp_files</varname> (<type>integer</type>)</term>
<indexterm>
@ -3980,17 +3995,18 @@ dynamic_library_path = 'C:\tools\postgresql;H:\my_project\lib;$libdir'
This is the amount of time, in milliseconds, to wait on a lock
before checking to see if there is a deadlock condition. The
check for deadlock is relatively slow, so the server doesn't run
it every time it waits for a lock. We (optimistically?) assume
it every time it waits for a lock. We optimistically assume
that deadlocks are not common in production applications and
just wait on the lock for a while before starting the check for a
deadlock. Increasing this value reduces the amount of time
wasted in needless deadlock checks, but slows down reporting of
real deadlock errors. The default is one second (<literal>1s</>),
which is probably about the smallest value you would want in
practice. On a heavily loaded server you might want to raise it.
practice. Set <xref linkend="guc-log-lock-waits"> to log deadlock
checks. On a heavily loaded server you might want to raise it.
Ideally the setting should exceed your typical transaction time,
so as to improve the odds that a lock will be released before
the waiter decides to check for deadlock.
so as to improve the odds that a lock will be released before the
waiter decides to check for deadlock.
</para>
</listitem>
</varlistentry>