Date: Mon, 26 Nov 2018 09:52:08 -0600
From: Justin Pryzby <pryzby@telsasoft.com>
To: Jakub Glapa <jakub.glapa@gmail.com>
Cc: pgsql-performance@postgresql.org,
	Thomas Munro <thomas.munro@enterprisedb.com>
Subject: Re: dsa_allocate() faliure
Message-ID: <20181126155207.GZ10913@telsasoft.com>
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Hi, thanks for following through.

On Mon, Nov 26, 2018 at 04:38:35PM +0100, Jakub Glapa wrote:
> I had a look at dmesg and indeed I see something like:
> 
> postgres[30667]: segfault at 0 ip 0000557834264b16 sp 00007ffc2ce1e030
> error 4 in postgres[557833db7000+6d5000]

That's useful, I think "at 0" means a null pointer dereferenced.

Can you check /var/log/messages (or ./syslog or similar) and verify the
timestamp matches the time of the last crash (and not an unrelated crash) ?

The logs might also indicate if the process dumped a core file anywhere. 

I don't know what distribution/OS you're using, but it might be good to install
abrt (RHEL) or apport (ubuntu) or other mechanism to save coredumps, or to
manually configure /proc/sys/kernel/core_pattern.

On centos, I usually set:
/etc/abrt/abrt-action-save-package-data.conf
OpenGPGCheck = no

Also, it might be good to install debug symbols, in case you do find a core
dump now or get one later.

On centos: yum install postgresql10-debuginfo or debuginfo-install postgresql10-server
Make sure this exactly matches the debug symbols exactly match the server version.

Justin