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Fix concurrent sequence drops during sequence synchronization.

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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 <vignesh21@gmail.com>
Reviewed-by: Hayato Kuroda <kuroda.hayato@fujitsu.com>
Reviewed-by: Amit Kapila <amit.kapila16@gmail.com>
Discussion: https://postgr.es/m/CALDaNm0FoGdt+1mzua0t-=wYdup5_zmFrvfNf-L=MGBnj9HAcg@mail.gmail.com
This commit is contained in:
Amit Kapila
2026-01-20 09:40:13 +00:00
parent 7ebb64c557
commit 1ba3eee89a
1 changed files with 25 additions and 8 deletions
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33
src/backend/replication/logical/sequencesync.c
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@@ -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;
}