Re: Unstable tests for recovery conflict handling

> On Apr 27, 2022, at 9:45 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>
> [ starting a new thread cuz the shared-stats one is way too long ]
>
> Andres Freund <andres(at)anarazel(dot)de> writes:
>> Add minimal tests for recovery conflict handling.
>
> It's been kind of hidden by other buildfarm noise, but
> 031_recovery_conflict.pl is not as stable as it should be [1][2][3][4].
>
> Three of those failures look like

Interesting,

I have been getting failures on REL_14_STABLE:

t/012_subtransactions.pl ............. 11/12
# Failed test 'Rollback of PGPROC_MAX_CACHED_SUBXIDS+ prepared transaction on promoted standby'
# at t/012_subtransactions.pl line 211.
# got: '3'
# expected: '0'
t/012_subtransactions.pl ............. 12/12 # Looks like you failed 1 test of 12.
t/012_subtransactions.pl ............. Dubious, test returned 1 (wstat 256, 0x100)
Failed 1/12 subtests

And the logs, tmp_check/log/regress_log_012_subtransactions, showing:

### Enabling streaming replication for node "primary"
### Starting node "primary"
# Running: pg_ctl -D /Users/mark.dilger/recovery_test/postgresql/src/test/recovery/tmp_check/t_012_subtransactions_primary_data/pgdata -l /Users/mark.dilger/recovery_test/postgresql/src/test/recovery/tmp_check/log/012_subtransactions_primary.log -o --cluster-name=primary start
waiting for server to start.... done
server started
# Postmaster PID for node "primary" is 46270
psql:<stdin>:1: ERROR: prepared transaction with identifier "xact_012_1" does not exist
not ok 11 - Rollback of PGPROC_MAX_CACHED_SUBXIDS+ prepared transaction on promoted standby

# Failed test 'Rollback of PGPROC_MAX_CACHED_SUBXIDS+ prepared transaction on promoted standby'
# at t/012_subtransactions.pl line 211.
# got: '3'
# expected: '0'

This is quite consistent for me, but only when I configure with --enable-coverage and --enable-dtrace. (I haven't yet tried one of those without the other.)

I wasn't going to report this yet, having not yet completely narrowed this down, but I wonder if anybody else is seeing this?

I'll try again on master....

—
Mark Dilger
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