From: DaeMyung Kang <charsyam@gmail.com>
To: pgsql-hackers@lists.postgresql.org
Cc: DaeMyung Kang <charsyam@gmail.com>
Subject: [PATCH] Use direct hash lookup in logicalrep_partmap_invalidate_cb()
Date: Sat, 18 Apr 2026 02:44:50 +0900
Message-ID: <20260417174450.4158878-1-charsyam@gmail.com>
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LogicalRepPartMap is keyed by the partition's OID, which is assigned
to entry->relmapentry.localreloid when the entry is populated in
logicalrep_partition_open().  The invalidation callback therefore
does not need to iterate over every entry to find the one matching
the invalidated relation OID; a single hash_search(HASH_FIND) on
reloid suffices.

This replaces an O(N) hash_seq_search loop with an O(1) lookup and
removes the longstanding "TODO, use inverse lookup hashtable?"
comment.  An Assert in logicalrep_partition_open() documents the
partOid == entry->relmapentry.localreloid invariant that the new
path relies on.
---

Tested on an --enable-cassert build: the full src/test/subscription
TAP suite (39 files, 579 tests) passes, including 013_partition.pl
which exercises the partmap invalidation path via ADD COLUMN on a
partitioned root (cascades a relcache inval to every leaf partition).

 src/backend/replication/logical/relation.c | 23 +++++++++-------------
 1 file changed, 9 insertions(+), 14 deletions(-)


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diff --git a/src/backend/replication/logical/relation.c b/src/backend/replication/logical/relation.c
index 0b1d80b5b0f..f6e2a9a6422 100644
--- a/src/backend/replication/logical/relation.c
+++ b/src/backend/replication/logical/relation.c
@@ -544,20 +544,14 @@ logicalrep_partmap_invalidate_cb(Datum arg, Oid reloid)
 
 	if (reloid != InvalidOid)
 	{
-		HASH_SEQ_STATUS status;
-
-		hash_seq_init(&status, LogicalRepPartMap);
-
-		/* TODO, use inverse lookup hashtable? */
-		while ((entry = (LogicalRepPartMapEntry *) hash_seq_search(&status)) != NULL)
-		{
-			if (entry->relmapentry.localreloid == reloid)
-			{
-				entry->relmapentry.localrelvalid = false;
-				hash_seq_term(&status);
-				break;
-			}
-		}
+		/*
+		 * LogicalRepPartMap is keyed by partition OID, which matches
+		 * entry->relmapentry.localreloid (see logicalrep_partition_open), so
+		 * we can invalidate via a direct hash lookup.
+		 */
+		entry = hash_search(LogicalRepPartMap, &reloid, HASH_FIND, NULL);
+		if (entry != NULL)
+			entry->relmapentry.localrelvalid = false;
 	}
 	else
 	{
@@ -676,6 +670,7 @@ logicalrep_partition_open(LogicalRepRelMapEntry *root,
 	 */
 	if (found && entry->localrelvalid)
 	{
+		Assert(entry->localreloid == partOid);
 		entry->localrel = partrel;
 		return entry;
 	}

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