From: Antonin Houska <ah@cybertec.at>
To: pgsql-hackers@lists.postgresql.org
Subject: Unexpected changes of CurrentResourceOwner and CurrentMemoryContext
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Date: Wed, 03 Sep 2025 11:49:32 +0200
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When working on the REPACK command, we see an ERROR caused by unexpected
change of CurrentResourceOwner [1]. I think the problem is that
reorderbuffer.c does not restore the original value after calling
RollbackAndReleaseCurrentSubTransaction(). The attached patch tries to handle
the call like other callers throughout the tree do.

[1]
https://www.postgresql.org/message-id/CADzfLwUgPMLiFkXRnk97ugPqkDfsNJ3TRdw9gjJM%3D8WB4_nXwQ%40mail.gmail.com

-- 
Antonin Houska
Web: https://www.cybertec-postgresql.com


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 filename=0001-Avoid-unexpected-changes-of-CurrentResourceOwner-and.patch

From 025322cd23c05fa92bb04c8e1ce76ef40003d4cc Mon Sep 17 00:00:00 2001
From: Antonin Houska <ah@cybertec.at>
Date: Wed, 3 Sep 2025 11:33:45 +0200
Subject: [PATCH] Avoid unexpected changes of CurrentResourceOwner and
 CurrentMemoryContext.

Users of logical decoding can encounter unexpected change of
CurrentResourceOwner and CurrentMemoryContext. The problem is that in
reorderbuffer.c, unlike other call sites, we call
RollbackAndReleaseCurrentSubTransaction() without restoring the original
values of these global variables. This patch saves the values prior to the
call and restores them eventually.
---
 src/backend/replication/logical/reorderbuffer.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c
index 34cf05668ae..4736f993c37 100644
--- a/src/backend/replication/logical/reorderbuffer.c
+++ b/src/backend/replication/logical/reorderbuffer.c
@@ -2215,6 +2215,7 @@ ReorderBufferProcessTXN(ReorderBuffer *rb, ReorderBufferTXN *txn,
 {
 	bool		using_subtxn;
 	MemoryContext ccxt = CurrentMemoryContext;
+	ResourceOwner cowner = CurrentResourceOwner;
 	ReorderBufferIterTXNState *volatile iterstate = NULL;
 	volatile XLogRecPtr prev_lsn = InvalidXLogRecPtr;
 	ReorderBufferChange *volatile specinsert = NULL;
@@ -2692,7 +2693,11 @@ ReorderBufferProcessTXN(ReorderBuffer *rb, ReorderBufferTXN *txn,
 		}
 
 		if (using_subtxn)
+		{
 			RollbackAndReleaseCurrentSubTransaction();
+			MemoryContextSwitchTo(ccxt);
+			CurrentResourceOwner = cowner;
+		}
 
 		/*
 		 * We are here due to one of the four reasons: 1. Decoding an
@@ -2751,7 +2756,11 @@ ReorderBufferProcessTXN(ReorderBuffer *rb, ReorderBufferTXN *txn,
 		}
 
 		if (using_subtxn)
+		{
 			RollbackAndReleaseCurrentSubTransaction();
+			MemoryContextSwitchTo(ccxt);
+			CurrentResourceOwner = cowner;
+		}
 
 		/*
 		 * The error code ERRCODE_TRANSACTION_ROLLBACK indicates a concurrent
@@ -3244,6 +3253,8 @@ ReorderBufferImmediateInvalidation(ReorderBuffer *rb, uint32 ninvalidations,
 								   SharedInvalidationMessage *invalidations)
 {
 	bool		use_subtxn = IsTransactionOrTransactionBlock();
+	MemoryContext ccxt = CurrentMemoryContext;
+	ResourceOwner cowner = CurrentResourceOwner;
 	int			i;
 
 	if (use_subtxn)
@@ -3262,7 +3273,11 @@ ReorderBufferImmediateInvalidation(ReorderBuffer *rb, uint32 ninvalidations,
 		LocalExecuteInvalidationMessage(&invalidations[i]);
 
 	if (use_subtxn)
+	{
 		RollbackAndReleaseCurrentSubTransaction();
+		MemoryContextSwitchTo(ccxt);
+		CurrentResourceOwner = cowner;
+	}
 }
 
 /*
-- 
2.47.1


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