Re: backend crash

Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com> writes:

> On Mon, Apr 13, 2020 at 11:01:01AM -0400, Tom Lane wrote:
>>Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)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.
2. I can try to prepare test data, but it will be rather long
process. Stay tuned :/
KJ
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