[Chao Li <li.evan.chao@gmail.com>]

Hi,

While working on a feature patch that I’m going to post soon, I noticed a small issue in reorderbuffer.c. In the REORDER_BUFFER_CHANGE_TRUNCATE branch of ReorderBufferProcessTXN(), some opened relations might be skipped without being closed, leading to leaked relcache references.

The relevant code is:
```
			relations = palloc0_array(Relation, nrelids);
			for (i = 0; i < nrelids; i++)
			{
				Oid			relid = change->data.truncate.relids[i];
				Relation	rel;

				rel = RelationIdGetRelation(relid);

				if (!RelationIsValid(rel))
					elog(ERROR, "could not open relation with OID %u", relid);

				if (!RelationIsLogicallyLogged(rel))
					continue;   <===== it should close rel before skipping it

				relations[nrelations++] = rel;
			}

			/* Apply the truncate. */
			ReorderBufferApplyTruncate(rb, txn, nrelations,
									   relations, change,
									   streaming);

			for (i = 0; i < nrelations; i++)
				RelationClose(relations[i]);
```

In the loop, each relation that is appended to relations is closed after the loop. However, when RelationIsLogicallyLogged(rel) returns false, the relation is skipped without being closed, causing the leak.

The attached patch makes a small fix to close the relation before continuing.

Best regards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/

Attachments:

  [application/octet-stream] v1-0001-Fix-relcache-reference-leak-when-decoding-TRUNCAT.patch (1.2K, ../7DD65D03-3B5A-43B2-99AD-8E6AF5372BAB@gmail.com/2-v1-0001-Fix-relcache-reference-leak-when-decoding-TRUNCAT.patch)
  download | inline diff:
From 30a53ee7a12f42181615a61e625596f6dd00014c Mon Sep 17 00:00:00 2001
From: "Chao Li (Evan)" <lic@highgo.com>
Date: Tue, 18 Aug 2026 11:37:54 +0800
Subject: [PATCH v1] Fix relcache reference leak when decoding TRUNCATE

ReorderBufferProcessTXN() opens every relation referenced by a
TRUNCATE change. When RelationIsLogicallyLogged() returns false,
it skips the relation without releasing the reference acquired
by RelationIdGetRelation().

Close the relation before continuing.

Author: Chao Li <lic@highgo.com>
---
 src/backend/replication/logical/reorderbuffer.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c
index 6aed6346366..b34ec5f2145 100644
--- a/src/backend/replication/logical/reorderbuffer.c
+++ b/src/backend/replication/logical/reorderbuffer.c
@@ -2492,7 +2492,10 @@ ReorderBufferProcessTXN(ReorderBuffer *rb, ReorderBufferTXN *txn,
 								elog(ERROR, "could not open relation with OID %u", relid);
 
 							if (!RelationIsLogicallyLogged(rel))
+							{
+								RelationClose(rel);
 								continue;
+							}
 
 							relations[nrelations++] = rel;
 						}
-- 
2.50.1 (Apple Git-155)

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