commit d0a862d09016b2c02811821644688cee2c33089d
Author: Alexey Masterov <alexey.masterov@databricks.com>
Date:   Wed May 6 11:01:31 2026 +0200

    xact: Prevent assertion failure in re-entrant AbortTransaction calls
    
    When an error occurs during AbortTransaction() after ProcArrayEndTransaction()
    has cleared MyProc->xid, subsequent abort attempts could pass a valid
    latestXid to ProcArrayEndTransaction() while proc->xid is already invalid,
    triggering Assert(TransactionIdIsValid(proc->xid)).
    
    Avoid this by checking MyProc->xid validity before calling
    RecordTransactionAbort() and only passing a valid latestXid when appropriate.

diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index 48bc90c9673..c7819d7d9d4 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -2979,7 +2979,20 @@ AbortTransaction(void)
 	 * record.
 	 */
 	if (!is_parallel_worker)
-		latestXid = RecordTransactionAbort(false);
+	{
+		/*
+		 * Re-entrant abort: if another ERROR is raised during AbortTransaction()
+		 * after ProcArrayEndTransaction() cleared our advertised XID, local
+		 * transaction state can still report an XID until CleanupTransaction().
+		 * Do not run RecordTransactionAbort again (duplicate WAL/clog) and do
+		 * not pass a valid latestXid to ProcArrayEndTransaction with proc->xid
+		 * already cleared.
+		 */
+		if (TransactionIdIsValid(MyProc->xid))
+			latestXid = RecordTransactionAbort(false);
+		else
+			latestXid = InvalidTransactionId;
+	}
 	else
 	{
 		latestXid = InvalidTransactionId;