v1-0001-Fix-LOCK_TIMEOUT-handling-in-slotsync-worker.patch

From 1921a4f3e8830aa894883140f1e7ff963ffc088e Mon Sep 17 00:00:00 2001
From: Zhijie Hou <houzj.fnst@fujitsu.com>
Date: Fri, 5 Dec 2025 17:53:50 +0800
Subject: [PATCH v1] Fix LOCK_TIMEOUT handling in slotsync worker.

Previously, the slotsync worker used SIGINT to receive a graceful shutdown
signal from the startup process on promotion. However, SIGINT is also used by
the LOCK_TIMEOUT handler to trigger a query-cancel interrupt, creating an
overlap that caused the slotsync worker to overlook LOCK_TIMEOUT signals.

This patch resolves this by replacing the current signal handler with the
appropriate StatementCancelHandler for SIGINT within the slotsync worker.
Furthermore, it updates the startup process to send a SIGUSR1 signal to notify
slotsync of the need to stop during promotion. The slotsync worker now stops
upon detecting that the shared memory flag (stopSignaled) is set to true.
---
 src/backend/replication/logical/slotsync.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c
index 31d7cb3ca77..28629ea9c07 100644
--- a/src/backend/replication/logical/slotsync.c
+++ b/src/backend/replication/logical/slotsync.c
@@ -1254,10 +1254,10 @@ ProcessSlotSyncInterrupts(void)
 {
 	CHECK_FOR_INTERRUPTS();
 
-	if (ShutdownRequestPending)
+	if (SlotSyncCtx->stopSignaled)
 	{
 		ereport(LOG,
-				errmsg("replication slot synchronization worker is shutting down on receiving SIGINT"));
+				errmsg("replication slot synchronization worker is shutting down because promotion is triggered"));
 
 		proc_exit(0);
 	}
@@ -1488,7 +1488,7 @@ ReplSlotSyncWorkerMain(const void *startup_data, size_t startup_data_len)
 
 	/* Setup signal handling */
 	pqsignal(SIGHUP, SignalHandlerForConfigReload);
-	pqsignal(SIGINT, SignalHandlerForShutdownRequest);
+	pqsignal(SIGINT, StatementCancelHandler);
 	pqsignal(SIGTERM, die);
 	pqsignal(SIGFPE, FloatExceptionHandler);
 	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
@@ -1595,7 +1595,8 @@ ReplSlotSyncWorkerMain(const void *startup_data, size_t startup_data_len)
 
 	/*
 	 * The slot sync worker can't get here because it will only stop when it
-	 * receives a SIGINT from the startup process, or when there is an error.
+	 * receives a stop request from the startup process, or when there is an
+	 * error.
 	 */
 	Assert(false);
 }
@@ -1680,8 +1681,12 @@ ShutDownSlotSync(void)
 
 	SpinLockRelease(&SlotSyncCtx->mutex);
 
+	/*
+	 * Signal slotsync worker if it was still running. The worker will stop upon
+	 * detecting that the stopSignaled flag is set to true.
+	 */
 	if (worker_pid != InvalidPid)
-		kill(worker_pid, SIGINT);
+		kill(worker_pid, SIGUSR1);
 
 	/* Wait for slot sync to end */
 	for (;;)
-- 
2.51.1.windows.1