Re: Adding REPACK [concurrently]

Hello Alvaro,

08.04.2026 00:38, Alvaro Herrera wrote:
> Okay. I implemented that now, and here it is. ...

Could you please look at an assertion failure produced by the following
script, starting from 0d3dba38c:?
createdb db1
createdb db2

echo "
CREATE TABLE t0 (a text);
BEGIN TRANSACTION ISOLATION LEVEL SERIALIZABLE;
INSERT INTO t0 VALUES ('a');
SELECT pg_sleep(1);
" | psql db1 &

echo "
CREATE TABLE t1 (id int PRIMARY KEY);
CREATE TABLE t2 (id int PRIMARY KEY, a TEXT, FOREIGN KEY (id) REFERENCES t1);
SET min_parallel_table_scan_size = 1;
REPACK (CONCURRENTLY) t2;
" | psql db2
wait

It triggers for me:
TRAP: failed Assert("TransactionIdPrecedesOrEquals(TransactionXmin, RecentXmin)"), File: "procarray.c", Line: 2071, PID:
3529520
postgres: parallel worker for PID 3529517 (ExceptionalCondition+0x69)[0x62f724b19c4c]
postgres: parallel worker for PID 3529517 (+0x522456)[0x62f72498e456]
postgres: parallel worker for PID 3529517 (GetSnapshotData+0x6b)[0x62f72498f50c]
postgres: parallel worker for PID 3529517 (GetNonHistoricCatalogSnapshot+0x4b)[0x62f724b5bd90]
postgres: parallel worker for PID 3529517 (GetCatalogSnapshot+0x20)[0x62f724b5ce7b]
postgres: parallel worker for PID 3529517 (systable_beginscan+0x10b)[0x62f7245c31e7]
postgres: parallel worker for PID 3529517 (+0x69e1e7)[0x62f724b0a1e7]
postgres: parallel worker for PID 3529517 (+0x69e5a6)[0x62f724b0a5a6]
postgres: parallel worker for PID 3529517 (+0x6a4d86)[0x62f724b10d86]
postgres: parallel worker for PID 3529517 (RelationIdGetRelation+0x83)[0x62f724b11208]
postgres: parallel worker for PID 3529517 (relation_open+0x1e)[0x62f72456c235]
...
2026-04-10 05:59:51.471 UTC [3529495] LOG:  background worker "parallel worker" (PID 3529520) was terminated by signal
6: Aborted

Best regards,
Alexander