From 1021fab97df6fb5b038d528ddba0bc9ca72a7c96 Mon Sep 17 00:00:00 2001 From: Ayush Tiwari Date: Tue, 28 Apr 2026 16:37:15 +0530 Subject: [PATCH v3] Fix stale relation close in sequence synchronization copy_sequences() processes publisher sequence data one result row at a time, but kept the Relation pointer used for the local sequence at batch scope. If pg_get_sequence_data() returned NULL sequence data for a later row, get_and_validate_seq_info() could return COPYSEQ_SKIPPED before assigning a new relation to that output argument. The caller could then close the stale Relation pointer left from the previous row, tripping the relcache refcount assertion in assert-enabled builds. This can happen due to concurrent drops or insufficient privileges, since pg_get_sequence_data() returns NULL data in those cases. Keep the caller-side Relation pointer local to each publisher result row and initialize the output Relation in get_and_validate_seq_info(), so early return paths cannot reuse a relation from a previous row. Add a subscription test that verifies insufficient privileges on one published sequence do not disrupt the subscriber. --- .../replication/logical/sequencesync.c | 8 +++-- src/test/subscription/t/036_sequences.pl | 35 +++++++++++++++++++ 2 files changed, 40 insertions(+), 3 deletions(-) diff --git a/src/backend/replication/logical/sequencesync.c b/src/backend/replication/logical/sequencesync.c index ec7e76abf93..6a2bb70e54e 100644 --- a/src/backend/replication/logical/sequencesync.c +++ b/src/backend/replication/logical/sequencesync.c @@ -246,6 +246,8 @@ get_and_validate_seq_info(TupleTableSlot *slot, Relation *sequence_rel, Form_pg_sequence local_seq; LogicalRepSequenceInfo *seqinfo_local; + *sequence_rel = NULL; + *seqidx = DatumGetInt32(slot_getattr(slot, ++col, &isnull)); Assert(!isnull); @@ -254,8 +256,8 @@ get_and_validate_seq_info(TupleTableSlot *slot, Relation *sequence_rel, (LogicalRepSequenceInfo *) list_nth(seqinfos, *seqidx); /* - * last_value can be NULL if the sequence was dropped concurrently (see - * pg_get_sequence_data()). + * The sequence data can be NULL due to insufficient privileges or if the + * sequence was dropped concurrently (see pg_get_sequence_data()). */ datum = slot_getattr(slot, ++col, &isnull); if (isnull) @@ -411,7 +413,6 @@ copy_sequences(WalReceiverConn *conn) int batch_skipped_count = 0; int batch_insuffperm_count = 0; int batch_missing_count; - Relation sequence_rel = NULL; WalRcvExecResult *res; TupleTableSlot *slot; @@ -494,6 +495,7 @@ copy_sequences(WalReceiverConn *conn) { CopySeqResult sync_status; LogicalRepSequenceInfo *seqinfo; + Relation sequence_rel = NULL; int seqidx; CHECK_FOR_INTERRUPTS(); diff --git a/src/test/subscription/t/036_sequences.pl b/src/test/subscription/t/036_sequences.pl index 471780a3585..a318f524617 100644 --- a/src/test/subscription/t/036_sequences.pl +++ b/src/test/subscription/t/036_sequences.pl @@ -221,4 +221,39 @@ $node_subscriber->wait_for_log( qr/WARNING: ( [A-Z0-9]+:)? missing sequence on publisher \("public.regress_s4"\)/, $log_offset); +########## +# Ensure that insufficient privileges on the publisher for a sequence do not +# disrupt the subscriber. The subscriber should log a warning and continue +# retrying. +########## + +$node_publisher->safe_psql( + 'postgres', qq( + CREATE ROLE regress_seq_repl LOGIN REPLICATION; + CREATE SEQUENCE regress_no_select; + GRANT USAGE ON SCHEMA public TO regress_seq_repl; + GRANT SELECT ON ALL SEQUENCES IN SCHEMA public TO regress_seq_repl; + REVOKE ALL ON SEQUENCE regress_no_select FROM regress_seq_repl; +)); + +$node_subscriber->safe_psql('postgres', + qq(CREATE SEQUENCE regress_no_select;)); + +my $publisher_limited_connstr = + $node_publisher->connstr . ' dbname=postgres user=regress_seq_repl'; +$log_offset = -s $node_subscriber->logfile; + +$node_subscriber->safe_psql( + 'postgres', + "CREATE SUBSCRIPTION regress_seq_sub_no_select CONNECTION '$publisher_limited_connstr' PUBLICATION regress_seq_pub WITH (disable_on_error = true)" +); + +$node_subscriber->wait_for_log( + qr/WARNING: ( [A-Z0-9]+:)? missing sequence on publisher \("public.regress_no_select"\)/, + $log_offset); + +$result = $node_subscriber->safe_psql('postgres', 'SELECT 1'); +is($result, '1', + 'subscriber remains running after publisher returns NULL sequence data'); + done_testing(); -- 2.34.1