Re: BUG #17695: Failed Assert in logical replication snapbuild.

On Fri, Nov 25, 2022 at 4:44 PM bowenshi <zxwsbg(at)qq(dot)com> wrote:
>
> Thanks for your advice! I update my test script, now it can 100% reproduce problem in my computer.

Hmm, I could not reproduce the issue even with the updated patch.

> The new script and fix code are both in the patch. However, I met new problem after adding fix code. It fails into a new trap following:
>
> TRAP: FailedAssertion("TransactionIdPrecedesOrEquals(safeXid, snap->xmin)", File: "snapbuild.c", Line: 593, PID: 1576)
> postgres: master: walsender postgres [local] CREATE_REPLICATION_SLOT(ExceptionalCondition+0xb9)[0xb1ca28]
> postgres: master: walsender postgres [local] CREATE_REPLICATION_SLOT(SnapBuildInitialSnapshot+0x1b3)[0x8f3c79]
> postgres: master: walsender postgres [local] CREATE_REPLICATION_SLOT[0x9136b9]
> postgres: master: walsender postgres [local] CREATE_REPLICATION_SLOT(exec_replication_command+0x398)[0x91456a]
> postgres: master: walsender postgres [local] CREATE_REPLICATION_SLOT(PostgresMain+0x7be)[0x984e4a]
> postgres: master: walsender postgres [local] CREATE_REPLICATION_SLOT[0x8c0d5b]
> postgres: master: walsender postgres [local] CREATE_REPLICATION_SLOT[0x8c06cd]
> postgres: master: walsender postgres [local] CREATE_REPLICATION_SLOT[0x8bc9de]
> postgres: master: walsender postgres [local] CREATE_REPLICATION_SLOT(PostmasterMain+0x117a)[0x8bc2b5]
> postgres: master: walsender postgres [local] CREATE_REPLICATION_SLOT[0x7bdb13]
>

Testing this script in some environments, I sometimes get this
assertion failure. I think this is the same issue that has been
reported in this thread[1]. I'll investigate this issue as well and
share my findings.

[1] https://www.postgresql.org/message-id/CAA4eK1L8wYcyTPxNzPGkhuO52WBGoOZbT0A73Le%3DZUWYAYmdfw%40mail.gmail.com

Regards,

--
Masahiko Sawada
Amazon Web Services: https://aws.amazon.com