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pgsql: Reject concurrent sequence refreshes. 2+ messages / 1 participants [nested] [flat]
* pgsql: Reject concurrent sequence refreshes. @ 2026-07-15 10:25 Amit Kapila <akapila@postgresql.org> 0 siblings, 0 replies; 2+ messages in thread From: Amit Kapila @ 2026-07-15 10:25 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Reject concurrent sequence refreshes. 'ALTER SUBSCRIPTION ... REFRESH SEQUENCES' can race with an already running sequence synchronization worker. If a second refresh request resets the synchronization state while the worker has already fetched sequence values from the publisher but has not yet applied them to the subscriber, the worker can overwrite the subscriber with stale values and mark the synchronization as complete. Avoid this race by rejecting 'ALTER SUBSCRIPTION ... REFRESH SEQUENCES' when a sequence synchronization worker is already running for the subscription. The command reports an error asking the user to rerun it after the current synchronization completes. Also add a wait for the re-added 'regress_s4' sequence to finish synchronizing in 036_sequences.pl, so the subsequent test does not race against its sequencesync worker. Reported-by: Noah Misch <noah@leadboat.com> Author: vignesh C <vignesh21@gmail.com> Reviewed-by: Shveta Malik <shveta.malik@gmail.com> Reviewed-by: Hayato Kuroda <kuroda.hayato@fujitsu.com> Reviewed-by: Amit Kapila <amit.kapila16@gmail.com> Backpatch-through: 19, where it was introduced Discussion: https://postgr.es/m/20260710045217.f0.noahmisch@microsoft.com Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/f38afa4abb04e85530c94b88daf11c089375daca Modified Files -------------- src/backend/commands/subscriptioncmds.c | 27 +++++++++++++++++++++++++++ src/test/subscription/t/036_sequences.pl | 4 ++++ 2 files changed, 31 insertions(+) ^ permalink raw reply [nested|flat] 2+ messages in thread
* pgsql: Reject concurrent sequence refreshes. @ 2026-07-15 10:25 Amit Kapila <akapila@postgresql.org> 0 siblings, 0 replies; 2+ messages in thread From: Amit Kapila @ 2026-07-15 10:25 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Reject concurrent sequence refreshes. 'ALTER SUBSCRIPTION ... REFRESH SEQUENCES' can race with an already running sequence synchronization worker. If a second refresh request resets the synchronization state while the worker has already fetched sequence values from the publisher but has not yet applied them to the subscriber, the worker can overwrite the subscriber with stale values and mark the synchronization as complete. Avoid this race by rejecting 'ALTER SUBSCRIPTION ... REFRESH SEQUENCES' when a sequence synchronization worker is already running for the subscription. The command reports an error asking the user to rerun it after the current synchronization completes. Also add a wait for the re-added 'regress_s4' sequence to finish synchronizing in 036_sequences.pl, so the subsequent test does not race against its sequencesync worker. Reported-by: Noah Misch <noah@leadboat.com> Author: vignesh C <vignesh21@gmail.com> Reviewed-by: Shveta Malik <shveta.malik@gmail.com> Reviewed-by: Hayato Kuroda <kuroda.hayato@fujitsu.com> Reviewed-by: Amit Kapila <amit.kapila16@gmail.com> Backpatch-through: 19, where it was introduced Discussion: https://postgr.es/m/20260710045217.f0.noahmisch@microsoft.com Branch ------ REL_19_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/928ed9b653e968ddb559a3fde7ff9a84b08f1196 Modified Files -------------- src/backend/commands/subscriptioncmds.c | 27 +++++++++++++++++++++++++++ src/test/subscription/t/036_sequences.pl | 4 ++++ 2 files changed, 31 insertions(+) ^ permalink raw reply [nested|flat] 2+ messages in thread
end of thread, other threads:[~2026-07-15 10:25 UTC | newest] Thread overview: 2+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2026-07-15 10:25 pgsql: Reject concurrent sequence refreshes. Amit Kapila <akapila@postgresql.org> 2026-07-15 10:25 pgsql: Reject concurrent sequence refreshes. Amit Kapila <akapila@postgresql.org>
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