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  1. Re: Assert when executing query on partitioned table

    Dmitry Koval <d.koval@postgrespro.ru> — 2025-12-18T23:27:34Z

    Hi!

Unfortunately, the issue is still relevant, so I'm updating the first
post and patches. I got an Assert when executing an "INSERT ... ON
CONFLICT ... UPDATE ..." query on partitioned table.

Reproduction order.
-------------------

1) Apply the patch
[v1-0001-Triggering-Assert-on-query-with-ON-CONFLICT.no_cfbot]
to "master" branch:

git am v1-0001-Triggering-Assert-on-query-with-ON-CONFLICT.no_cfbot

2) Build postgres with "--enable-injection-points --enable-cassert",
for example:

./configure --enable-injection-points --enable-debug --enable-cassert 
 >/dev/null && make -j4 -s

3) Run isolation test onconflict.spec:

make check -C src/test/modules/injection_points

Assert is triggered in postgres, with part of stack:
...
#3  0x0000624cb170e05f in ExceptionalCondition (
     conditionName=conditionName@entry=0x624cb17fcbf0 
"!ItemPointerIndicatesMovedPartitions(&tmfd.ctid)",
     fileName=fileName@entry=0x624cb1785ea7 "nodeModifyTable.c", 
lineNumber=lineNumber@entry=2819) at assert.c:65
#4  0x0000624cb13f1412 in ExecOnConflictUpdate (returning=<synthetic 
pointer>, canSetTag=true, excludedSlot=0x624cb2a61750,
     conflictTid=0x7fff95cd827a, resultRelInfo=0x624cb2a62420, 
context=0x7fff95cd8340) at nodeModifyTable.c:2819
...

Clarification.
--------------
In the query "INSERT ... ON CONFLICT ... UPDATE ..." when executing
INSERT, a conflict is triggered. But when trying to execute UPDATE, our
tuple has already been moved to another partition and Assert is
triggered. I think this is a correct situation and in this case we
should generate an error instead of Assert.

Fixing.
-------
Patch [v1-0001-Replace-invalid-Assert-with-ereport-ERROR.patch].
For testing need to apply
[v1-0001-Replace-invalid-Assert-with-ereport-ERROR.patch]:

git am v1-0001-Replace-invalid-Assert-with-ereport-ERROR.patch

rebuild postgres (2) and run test again (3),

-- 
With best regards,
Dmitry Koval

Postgres Professional: http://postgrespro.com