Re: generic plans and "initial" pruning

Hello Amit,

06.02.2025 04:35, Amit Langote wrote:
> I plan to push 0001 tomorrow, barring any objections.
>

Please try the following script:
CREATE TABLE pt (a int, b int) PARTITION BY range (a);
CREATE TABLE tp1 PARTITION OF pt FOR VALUES FROM (1) TO (2);
CREATE TABLE tp2 PARTITION OF pt FOR VALUES FROM (2) TO (3);

MERGE INTO pt
USING (SELECT pg_backend_pid() AS pid) AS q JOIN tp1 ON (q.pid = tp1.a)
ON pt.a = tp1.a
WHEN MATCHED THEN DELETE;

which fails for me with segfault:
Program terminated with signal SIGSEGV, Segmentation fault.
#0  ExecInitMerge (mtstate=0x5a9b9fbccae0, estate=0x5a9b9fbcbe20) at nodeModifyTable.c:3680
3680                    relationDesc = RelationGetDescr(resultRelInfo->ri_RelationDesc);
(gdb) bt
#0  ExecInitMerge (mtstate=0x5a9b9fbccae0, estate=0x5a9b9fbcbe20) at nodeModifyTable.c:3680
#1  0x00005a9b67e6dfb5 in ExecInitModifyTable (node=0x5a9b9fbd5858, estate=0x5a9b9fbcbe20, eflags=0) at
nodeModifyTable.c:4906
#2  0x00005a9b67e273f7 in ExecInitNode (node=0x5a9b9fbd5858, estate=0x5a9b9fbcbe20, eflags=0) at execProcnode.c:177
#3  0x00005a9b67e1b9d2 in InitPlan (queryDesc=0x5a9b9fbb9970, eflags=0) at execMain.c:1092
#4  0x00005a9b67e1a524 in standard_ExecutorStart (queryDesc=0x5a9b9fbb9970, eflags=0) at execMain.c:268
#5  0x00005a9b67e1a223 in ExecutorStart (queryDesc=0x5a9b9fbb9970, eflags=0) at execMain.c:142
...

starting from cbc127917.

(I've discovered this anomaly with SQLsmith.)

Best regards,
Alexander Lakhin
Neon (https://neon.tech)