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The default values for shared_buffers and max_connections are now 1000

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and 100 respectively, if the platform will allow it.  initdb selects
values that are not too large to allow the postmaster to start, and
places these values in the installed postgresql.conf file.  This allows
us to continue to start up out-of-the-box on platforms with small SHMMAX,
while having somewhat-realistic default settings on platforms with
reasonable SHMMAX.  Per recent pghackers discussion.
This commit is contained in:
Tom Lane
2003-07-14 20:00:23 +00:00
parent 8460000069
commit de98a7e23a
5 changed files with 97 additions and 88 deletions
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36
doc/src/sgml/runtime.sgml
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@ -1,5 +1,5 @@
<!--
$Header: /cvsroot/pgsql/doc/src/sgml/runtime.sgml,v 1.192 2003/07/09 08:52:56 momjian Exp $
$Header: /cvsroot/pgsql/doc/src/sgml/runtime.sgml,v 1.193 2003/07/14 20:00:22 tgl Exp $
-->
<Chapter Id="runtime">
@ -608,9 +608,18 @@ SET ENABLE_SEQSCAN TO OFF;
<listitem>
<para>
Determines the maximum number of concurrent connections to the
database server. The default is 32 (unless altered while
building the server). This parameter can only be set at server
start.
database server. The default is typically 100, but may be less
if your kernel settings will not support it (as determined
during <application>initdb</>).
This parameter can only be set at server start.
</para>
<para>
Increasing this parameter may cause <productname>PostgreSQL</>
to request more <systemitem class="osname">System V</> shared
memory or semaphores than your operating system's default configuration
allows. See <xref linkend="sysvipc"> for information on how to
adjust these parameters, if necessary.
</para>
</listitem>
</varlistentry>
@ -831,13 +840,16 @@ SET ENABLE_SEQSCAN TO OFF;
<listitem>
<para>
Sets the number of shared memory buffers used by the database
server. The default is 64. Each buffer is typically 8192
bytes. This must be greater than 16, as well as at least twice
the value of <varname>MAX_CONNECTIONS</varname>; however, a
higher value can often improve performance.
Values of a few thousand are recommended
for production installations. This option can only be set at
server start.
server. The default is typically 1000, but may be less
if your kernel settings will not support it (as determined
during <application>initdb</>). Each buffer is 8192
bytes, unless a different value of <literal>BLCKSZ</> was chosen
when building the server. This setting must be at least 16,
as well as at least twice the value of
<varname>MAX_CONNECTIONS</varname>; however, settings significantly
higher than the minimum are usually needed for good performance.
Values of a few thousand are recommended for production installations.
This option can only be set at server start.
</para>
<para>
@ -2796,7 +2808,7 @@ $ <userinput>postmaster -o '-S 1024 -s'</userinput>
number</quote>, to detect collision with semaphore sets used by
other applications. The maximum number of semaphores in the system
is set by <varname>SEMMNS</>, which consequently must be at least
as high as the connection setting plus one extra for each 16
as high as <literal>max_connections</> plus one extra for each 16
allowed connections (see the formula in <xref
linkend="sysvipc-parameters">). The parameter <varname>SEMMNI</>
determines the limit on the number of semaphore sets that can