[test](regression) Target publish debug point on master FE

regression-test/suites/insert_p0/test_insert_visible_timeout_return_mode.groovy

@@ -25,10 +25,6 @@ suite("test_insert_visible_timeout_return_mode", "nonConcurrent") {
 
     def tableName = "test_insert_visible_timeout_return_mode_tbl"
     def debugPoint = "PublishVersionDaemon.stop_publish"
-    // Use the configured FE HTTP endpoint so the case also works when SHOW FRONTENDS exposes loopback addresses.
-    def feHttpAddress = context.config.feHttpAddress
-    def feHost = feHttpAddress.split(":")[0]
-    def feHttpPort = Integer.parseInt(feHttpAddress.split(":")[1])
 
     // Prepare a single-replica table so publish blocking deterministically drives the visible timeout path.
     sql """ DROP TABLE IF EXISTS ${tableName} FORCE """
@@ -43,9 +39,15 @@ suite("test_insert_visible_timeout_return_mode", "nonConcurrent") {
         )
     """
 
+    def masterFe = sql_return_maparray("SHOW FRONTENDS").find { it.IsMaster == "true" }
+    assertNotNull(masterFe, "Could not find master FE")
+    def masterFeHost = masterFe.Host as String
+    def masterFeHttpPort = masterFe.HttpPort as int
+
     try {
-        // Block FE publish so inserts can commit but remain non-visible until the debug point is removed.
-        DebugPoint.enableDebugPoint(feHost, feHttpPort, NodeType.FE, debugPoint)
+        // PublishVersionDaemon only runs on the master FE. Keep the SQL connection unchanged and
+        // inject the fault directly into the master identified by the same SHOW FRONTENDS snapshot.
+        DebugPoint.enableDebugPoint(masterFeHost, masterFeHttpPort, NodeType.FE, debugPoint)
 
         sql """ SET insert_visible_timeout_ms = 1000 """
 
@@ -61,7 +63,7 @@ suite("test_insert_visible_timeout_return_mode", "nonConcurrent") {
         }
     } finally {
         try {
-            DebugPoint.disableDebugPoint(feHost, feHttpPort, NodeType.FE, debugPoint)
+            DebugPoint.disableDebugPoint(masterFeHost, masterFeHttpPort, NodeType.FE, debugPoint)
         } catch (Throwable e) {
             logger.warn("Failed to disable debug point ${debugPoint}", e)
         }