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From: Tom Lane <tgl@sss.pgh.pa.us>
To: pgsql-hackers@lists.postgresql.org
Subject: Recent pg_rewind test failures in buildfarm
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Date: Mon, 14 Apr 2025 22:58:28 -0400
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In the last day or so, both skink and mamba have hit this
in the pg_rewind test suite [1][2]:

#3  0x01f03f7c in ExceptionalCondition (conditionName=3DconditionName@entr=
y=3D0x2119c4c "pending_since =3D=3D 0", fileName=3DfileName@entry=3D0x2119=
454 "pgstat.c", lineNumber=3DlineNumber@entry=3D734) at assert.c:66
#4  0x01d7994c in pgstat_report_stat (force=3Dforce@entry=3Dtrue) at pgsta=
t.c:734
#5  0x01d7a248 in pgstat_shutdown_hook (code=3D<optimized out>, arg=3D<opt=
imized out>) at pgstat.c:615
#6  0x01d1e7c0 in shmem_exit (code=3Dcode@entry=3D0) at ipc.c:243
#7  0x01d1e92c in proc_exit_prepare (code=3Dcode@entry=3D0) at ipc.c:198
#8  0x01d1e9fc in proc_exit (code=3D0) at ipc.c:111
#9  0x01cd5bd0 in ProcessRepliesIfAny () at walsender.c:2294
#10 0x01cd8084 in WalSndLoop (send_data=3Dsend_data@entry=3D0x1cd7628 <XLo=
gSendPhysical>) at walsender.c:2790
#11 0x01cd8f40 in StartReplication (cmd=3D0xfd048210) at walsender.c:960
#12 exec_replication_command (cmd_string=3Dcmd_string@entry=3D0xfd53c098 "=
START_REPLICATION 0/3000000 TIMELINE 2") at walsender.c:2135
#13 0x01d5bd84 in PostgresMain (dbname=3D<optimized out>, username=3D<opti=
mized out>) at postgres.c:4767

That assert appears to be several years old, and the
008_min_recovery_point.pl test script that's triggering it hasn't
changed very recently either, so I'm baffled where to start digging.
It has the odor of a timing problem, so maybe we just started hitting
this by chance.  Still ... anybody have an idea?

			regards, tom lane

[1] https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=3Dskink&dt=3D2=
025-04-13%2018%3A55%3A03
[2] https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=3Dmamba&dt=3D2=
025-04-15%2001%3A00%3A04