Subject: Regarding Overcommit

From: [email-masked]
Date: Mon, 13 Jun 2016 07:00:56 +0000

The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/9.2/static/kernel-resources.html
Description:

Documentation says:

sysctl -w vm.overcommit_memory=2

&quot;it will lower the chances significantly and will therefore lead to more
robust system behavior.&quot;

This statement in documentation is Wrong.

This is not recommended for production environments, because if an
out-of-memory condition does present itself, there could be unexpected
behavior.

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From: Kevin Grittner <[email-masked]>
Date: Mon, 13 Jun 2016 13:59:31 -0500

> out-of-memory condition does present itself, there could be unexpected

It is wrong for some types of production environments, but for a
server where the only (or primary) service is PostgreSQL it is
absolutely Right.  Without this, an out-of-memory condition which
cancels any database process causes a crash and restart of all
connections without necessarily giving any useful clues as to the
cause of the crash.  With vm.overcommit_memory = 2 it will
generally yield an error on only the one connection causing the
problem, and provide a detailed dump of memory contexts (with
allocated space in each).  Other connections are generally
unaffected and the cause of the problem can be fixed to prevent
recurrence.

--
Kevin Grittner
EDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company