Re: backend crash

On Mon, Apr 13, 2020 at 06:19:13PM +0200, Tomas Vondra wrote:
>On Mon, Apr 13, 2020 at 06:02:34PM +0200, Kamil Jońca wrote:
>>Tomas Vondra <tomas.vondra@2ndquadrant.com> writes:
>>
>>>On Mon, Apr 13, 2020 at 11:01:01AM -0400, Tom Lane wrote:
>>>>Tomas Vondra <tomas.vondra@2ndquadrant.com> writes:
>>>>>On Mon, Apr 13, 2020 at 09:25:35AM +0200, Kamil Jońca wrote:
>>>>>>I have problem with (pseudo) random backend crashes.
>>>>>>They seems to happen at one query, but not every time.
>>>>
>>>>>I've tried to reproduce this, but unfortunately it does not fail for me.
>>>>>Chances are this depends on data. Can you prepare a small data sample
>>>>>that would trigger the issue?
>>>>
>>>>This is evidently a parallel-query worker, so it's unlikely you'd ever
>>>>get anywhere near this crash with a "small" data sample; for starters
>>>>there'd have to be enough data to prompt use of a parallel plan.
>>>>
>>>>I doubt that the crash is very data-specific though.  Maybe just fill
>>>>the table with a lot of dummy data?
>>>>
>>>
>>>I did that, of course, and the plan looks like this:
>>>
>>
>>1. Did you try run this many times? As I wrote this does not crash every
>>time. I can reproduce this on my data by running query 1000 times in
>>loop.
>
>I did run it about 100x, I'll reduce the amount of data and let it run.
>
>How often it crashes? What execution plan does it use?
>

Also, presumably you're building from source, right? What configure
options are you using?


regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services