Add note that the logging collector can block backends in high load situations.

This commit is contained in:
Alvaro Herrera 2009-09-10 15:02:46 +00:00
parent f82d4d5302
commit 19fd0c2e56

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@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.225 2009/09/08 17:08:36 tgl Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.226 2009/09/10 15:02:46 alvherre Exp $ -->
<chapter Id="runtime-config">
<title>Server Configuration</title>
@ -2422,6 +2422,19 @@ local0.* /var/log/postgresql
is dynamic-linker failure messages).
This parameter can only be set at server start.
</para>
<note>
<para>
The logging collector is designed to never lose messages. This means
that in case of extremely high load, server processes could be
blocked due to trying to send additional log messages when the
collector has fallen behind. In contrast, <application>syslog</>
prefers to drop messages if it cannot write them, which means it's
less reliable in those cases but it will not block the rest of the
system.
</para>
</note>
</listitem>
</varlistentry>