Subject: [PATCH] Avoid unexpected changes of CurrentResourceOwner and CurrentMemoryContext.

From: Antonin Houska <[email-masked]>
Date: Wed, 3 Sep 2025 11:33:45 +0200

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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