From 0d19b7d31ace4a5b1abc5065d71312278a2bad41 Mon Sep 17 00:00:00 2001 From: Vignesh C Date: Mon, 19 Jan 2026 18:25:23 +0530 Subject: [PATCH v3] Fix concurrent sequence drops during sequence synchronization. A recent BF failure showed that commit 7a485bd641 did not handle the case where a sequence is dropped concurrently during sequence synchronization on the subscriber. Previously, pg_get_sequence_data() would ERROR out if the sequence was dropped concurrently. After 7a485bd641, it instead returns NULL, which leads to an assertion failure on the subscriber. To handle this change, update sequence synchronization to skip sequences for which pg_get_sequence_data() returns NULL. Author: vignesh C Reviewed-by: Hayato Kuroda Reviewed-by: Amit Kapila --- .../replication/logical/sequencesync.c | 33 ++++++++++++++----- 1 file changed, 25 insertions(+), 8 deletions(-) diff --git a/src/backend/replication/logical/sequencesync.c b/src/backend/replication/logical/sequencesync.c index 509388d1bf4..165f909b3ba 100644 --- a/src/backend/replication/logical/sequencesync.c +++ b/src/backend/replication/logical/sequencesync.c @@ -233,6 +233,7 @@ get_and_validate_seq_info(TupleTableSlot *slot, Relation *sequence_rel, { bool isnull; int col = 0; + Datum datum; Oid remote_typid; int64 remote_start; int64 remote_increment; @@ -251,8 +252,14 @@ get_and_validate_seq_info(TupleTableSlot *slot, Relation *sequence_rel, *seqinfo = seqinfo_local = (LogicalRepSequenceInfo *) list_nth(seqinfos, *seqidx); - seqinfo_local->last_value = DatumGetInt64(slot_getattr(slot, ++col, &isnull)); - Assert(!isnull); + /* + * last_value can be NULL if the sequence was dropped concurrently (see + * pg_get_sequence_data()). + */ + datum = slot_getattr(slot, ++col, &isnull); + if (isnull) + return COPYSEQ_SKIPPED; + seqinfo_local->last_value = DatumGetInt64(datum); seqinfo_local->is_called = DatumGetBool(slot_getattr(slot, ++col, &isnull)); Assert(!isnull); @@ -400,7 +407,7 @@ copy_sequences(WalReceiverConn *conn) int batch_skipped_count = 0; int batch_insuffperm_count = 0; int batch_missing_count; - Relation sequence_rel; + Relation sequence_rel = NULL; WalRcvExecResult *res; TupleTableSlot *slot; @@ -535,11 +542,21 @@ copy_sequences(WalReceiverConn *conn) batch_insuffperm_count++; break; case COPYSEQ_SKIPPED: - ereport(LOG, - errmsg("skip synchronization of sequence \"%s.%s\" because it has been dropped concurrently", - seqinfo->nspname, - seqinfo->seqname)); - batch_skipped_count++; + + /* + * Concurrent removal of a sequence on the subscriber is + * treated as success, since the only viable action is to + * skip the corresponding sequence data. Missing sequences + * on the publisher are treated as ERROR. + */ + if (seqinfo->found_on_pub) + { + ereport(LOG, + errmsg("skip synchronization of sequence \"%s.%s\" because it has been dropped concurrently", + seqinfo->nspname, + seqinfo->seqname)); + batch_skipped_count++; + } break; } -- 2.43.0