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Don't choose an invalid index for REPLICA IDENTITY FULL lookups.

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For a REPLICA IDENTITY FULL remote relation whose local counterpart has
no primary key or replica identity, FindUsableIndexForReplicaIdentityFull()
chooses the first index of a suitable shape from RelationGetIndexList().
That list excludes only indexes that are not indislive, so an invalid
index left behind by a failed CREATE INDEX CONCURRENTLY can be selected.

Such an index need not contain every row. Consequently, changes for rows
that it fails to find can be silently dropped as missing-tuple conflicts.
If the index contains no rows at all, the scan can instead error out and
cause the apply worker to exit.

Skip invalid indexes, as the planner does.

Author: Mikhail Nikalayeu <mihailnikalayeu@gmail.com>
Reviewed-by: Miłosz Bieniek <bieniek.milosz@proton.me>
Reviewed-by: Amit Kapila <amit.kapila16@gmail.com>
Reviewed-by: Shlok Kyal <shlok.kyal.oss@gmail.com>
Reviewed-by: Vignesh C <vignesh21@gmail.com>
Reviewed-by: Ajin Cherian <itsajin@gmail.com>
Discussion: https://postgr.es/m/CADzfLwWuubcbJBDRZ_J1SSqHDNjNmUYSAgf5y=17LxmP401xbw@mail.gmail.com
Backpatch-through: 16, where it was introduced
This commit is contained in:
Amit Kapila
2026-08-27 10:05:51 +05:30
parent 073bd83277
commit 3c73b272b4
2 changed files with 74 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
src/backend/replication/logical/relation.c
View File

@@ -796,7 +796,17 @@ FindUsableIndexForReplicaIdentityFull(Relation localrel, AttrMap *attrmap)
Relation idxRel;
idxRel = index_open(idxoid, AccessShareLock);
isUsableIdx = IsIndexUsableForReplicaIdentityFull(idxRel, attrmap);
/*
* indisvalid is checked here, not in
* IsIndexUsableForReplicaIdentityFull(), since that function's other
* caller (an assertion) must tolerate an index made transiently
* invalid by a concurrent DROP INDEX CONCURRENTLY, whereas a
* permanently invalid leftover of a failed CREATE INDEX CONCURRENTLY
* must never be chosen here.
*/
isUsableIdx = idxRel->rd_index->indisvalid &&
IsIndexUsableForReplicaIdentityFull(idxRel, attrmap);
index_close(idxRel, AccessShareLock);
/* Return the first eligible index found */
@@ -819,6 +829,10 @@ FindUsableIndexForReplicaIdentityFull(Relation localrel, AttrMap *attrmap)
* map to check whether the local index attribute has a corresponding remote
* attribute.
*
* Note that this function does not check indisvalid. Callers that are
* selecting an index to use for future lookups must check indisvalid
* themselves and reject invalid indexes.
*
* Note that the limitations of index scans for replica identity full only
* adheres to a subset of the limitations of PK/RI. For example, we support
* columns that are marked as [NULL] or we are not interested in the [NOT

59
src/test/subscription/t/032_subscribe_use_index.pl
View File

@@ -478,6 +478,65 @@ $node_subscriber->safe_psql('postgres', "DROP TABLE test_replica_id_full");
# data
# =============================================================================
# =============================================================================
# Testcase start: Subscription does not use an invalid index
#
# A failed CREATE INDEX CONCURRENTLY leaves behind a live but invalid
# index, which is not required to contain every row. The apply worker
# must not choose it for REPLICA IDENTITY FULL lookups.
#
# create tables pub and sub
$node_publisher->safe_psql('postgres',
"CREATE TABLE test_invalid (x int, y int)");
$node_publisher->safe_psql('postgres',
"ALTER TABLE test_invalid REPLICA IDENTITY FULL");
$node_subscriber->safe_psql('postgres',
"CREATE TABLE test_invalid (x int, y int)");
# insert some initial data, including the row the index build trips over
$node_publisher->safe_psql('postgres',
"INSERT INTO test_invalid SELECT i, i FROM generate_series(1,10) i");
# create pub/sub
$node_publisher->safe_psql('postgres',
"CREATE PUBLICATION tap_pub_invalid FOR TABLE test_invalid");
$node_subscriber->safe_psql('postgres',
"CREATE SUBSCRIPTION tap_sub_invalid CONNECTION '$publisher_connstr application_name=$appname' PUBLICATION tap_pub_invalid"
);
# wait for initial table synchronization to finish
$node_subscriber->wait_for_subscription_sync($node_publisher, $appname);
# leave an invalid index behind: the build fails on the y = 5 row
my ($cic_ret, $cic_out, $cic_err) = $node_subscriber->psql('postgres',
"CREATE INDEX CONCURRENTLY test_invalid_idx ON test_invalid (x, (1/(y-5)))"
);
isnt($cic_ret, 0, 'CREATE INDEX CONCURRENTLY fails');
$result = $node_subscriber->safe_psql('postgres',
"SELECT indisvalid FROM pg_index"
. " WHERE indexrelid = 'test_invalid_idx'::regclass");
is($result, qq(f), 'and leaves an invalid index behind');
# the update must still be applied
$node_publisher->safe_psql('postgres',
"UPDATE test_invalid SET y = 99 WHERE x = 7");
$node_publisher->wait_for_catchup($appname);
$result = $node_subscriber->safe_psql('postgres',
"SELECT y FROM test_invalid WHERE x = 7");
is($result, qq(99),
'ensure subscriber has the correct data at the end of the test');
# cleanup pub
$node_publisher->safe_psql('postgres', "DROP PUBLICATION tap_pub_invalid");
$node_publisher->safe_psql('postgres', "DROP TABLE test_invalid");
# cleanup sub
$node_subscriber->safe_psql('postgres', "DROP SUBSCRIPTION tap_sub_invalid");
$node_subscriber->safe_psql('postgres', "DROP TABLE test_invalid");
# Testcase end: Subscription does not use an invalid index
# =============================================================================
# =============================================================================
# Testcase start: Subscription can use hash index
#