Re: postmaster deadlock while logging after syslogger exited

Andres Freund <andres(at)anarazel(dot)de> writes:
> On 2017-11-16 21:39:49 -0500, Tom Lane wrote:
>> What might be worth thinking about is allowing the syslogger process to
>> inherit the postmaster's OOM-kill-proofness setting, instead of dropping
>> down to the same vulnerability as the postmaster's other child processes.

> Hm. I'm a bit scared about that - it doesn't seem that inconceivable
> that various backends log humongous multi-line messages, leading to
> syslogger *actually* taking up a fair amount of memory. Note that we're
> using plain stringinfos that ereport(ERROR) out of memory situations,
> rather than failing more gracefully.

True, but there's no hard limits on the postmaster's memory consumption
either ... and if the syslogger does get killed on such a basis, we have
at the least lost a bunch of log output. On the whole I think we'd be
better off trying to prevent OOM kills on the syslogger. (That doesn't
preclude other mitigation measures.)

regards, tom lane