Re: Why is parula failing?

On 4/9/24 05:48, David Rowley wrote:
> On Mon, 8 Apr 2024 at 23:56, Robins Tharakan <tharakan(at)gmail(dot)com> wrote:
>> #3 0x000000000083ed84 in WaitLatch (latch=<optimized out>, wakeEvents=wakeEvents(at)entry=41, timeout=600000, wait_event_info=wait_event_info(at)entry=150994946) at latch.c:538
>> #4 0x0000000000907404 in pg_sleep (fcinfo=<optimized out>) at misc.c:406
>
>> #17 0x000000000086a944 in exec_simple_query (query_string=query_string(at)entry=0x28171c90 "SELECT pg_sleep(0.1);") at postgres.c:1274
>
> I have no idea why WaitLatch has timeout=600000. That should be no
> higher than timeout=100 for "SELECT pg_sleep(0.1);". I have no
> theories aside from a failing RAM module, cosmic ray or a well-timed
> clock change between the first call to gettimeofday() in pg_sleep()
> and the next one.
>
> I know this animal is running debug_parallel_query = regress, so that
> 0.1 Const did have to get serialized and copied to the worker, so
> there's another opportunity for the sleep duration to be stomped on,
> but that seems pretty unlikely.
>

AFAIK that GUC is set only for HEAD, so it would not explain the
failures on the other branches.

> I can't think of a reason why the erroneous reltuples=48 would be
> consistent over 2 failing runs if it were failing RAM or a cosmic ray.
>

Yeah, that seems very unlikely.

regards

--
Tomas Vondra
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