From: Tom Lane <tgl@sss.pgh.pa.us>
To: Thomas Munro <thomas.munro@enterprisedb.com>
cc: Jakub Glapa <jakub.glapa@gmail.com>,
        Forums postgresql <pgsql-general@postgresql.org>
Subject: Re: ERROR: too many dynamic shared memory segments
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Comments: In-reply-to Thomas Munro <thomas.munro@enterprisedb.com>
	message dated "Tue, 28 Nov 2017 07:53:46 +1300"
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Date: Mon, 27 Nov 2017 14:16:25 -0500
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Thomas Munro <thomas.munro@enterprisedb.com> writes:
> Ah, so you have many Gather nodes under Append?  That's one way to eat
> arbitrarily many DSM slots.  We allow for 64 + 2 * max_backends.  Does
> it help if you increase max_connections?  I am concerned about the
> crash failure mode you mentioned in the first email though: we should
> always be able to handle that condition gracefully.

I suspect this is an instance of the issue I complained about before [1]
that parallel query is unable to cope with worker start failure.

			regards, tom lane

[1] https://www.postgresql.org/message-id/4905.1492813727@sss.pgh.pa.us