From: Tom Lane <tgl@sss.pgh.pa.us>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
cc: pgsql-hackers@lists.postgresql.org
Subject: Re: Repeated crashes in GENERATED ... AS IDENTITY tests
In-reply-to: <20180419204946.5ujino6w4dy7biuc@alvherre.pgsql>
References: <20180419204946.5ujino6w4dy7biuc@alvherre.pgsql>
Comments: In-reply-to Alvaro Herrera <alvherre@alvh.no-ip.org>
	message dated "Thu, 19 Apr 2018 17:49:46 -0300"
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Date: Thu, 19 Apr 2018 17:23:07 -0400
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Alvaro Herrera <alvherre@alvh.no-ip.org> writes:
> Of the machines you listed, conchuela has gdb installed, which gives us
> a nice backtrace of the crash, pasted below, which seems to blame event
> triggers.  Of the tests in the same parallel group as identity, the test
> fast_default seems to be the only one with an event trigger and was
> added on March 28th by 16828d5c0273.  That combination seems to explain
> why the crashes appeared late ...

Hm.  Our past policy has been that tests involving event triggers must not
run in parallel with any other test, precisely because the event triggers
interact with anything else happening at the same time, and will
inevitably create irreproducible test failures.

I'm inclined to say that whether or not there's a bug here (and there
well may be, it doesn't seem like a crash is a good thing), this is
bad test design and we need to change it.

			regards, tom lane