mdl_dbug_print_locks(): make it useful in gdb too

sql/mdl.cc

@@ -224,6 +224,35 @@ class Deadlock_detection_visitor: public MDL_wait_for_graph_visitor
   static const uint MAX_SEARCH_DEPTH= 32;
 };
 
+#ifndef DBUG_OFF
+
+/*
+  Print a list of all locks to DBUG trace to help with debugging
+*/
+
+static int mdl_dbug_print_lock(MDL_ticket *mdl_ticket, void *arg, bool granted)
+{
+  String *tmp= (String*) arg;
+  char buffer[128];
+  MDL_key *mdl_key= mdl_ticket->get_key();
+  size_t length;
+  length= my_snprintf(buffer, sizeof(buffer)-1,
+                      "\nname: %s  db: %.*s  key_name: %.*s (%s)",
+                      mdl_ticket->get_type_name()->str,
+                      (int) mdl_key->db_name_length(), mdl_key->db_name(),
+                      (int) mdl_key->name_length(),    mdl_key->name(),
+                      granted ? "granted" : "waiting");
+  tmp->append(buffer, length);
+  return 0;
+}
+
+const char *mdl_dbug_print_locks()
+{
+  static String tmp;
+  mdl_iterate(mdl_dbug_print_lock, (void*) &tmp);
+  return tmp.c_ptr();
+}
+#endif /* DBUG_OFF */
 
 /**
   Enter a node of a wait-for graph. After
@@ -2358,7 +2387,9 @@ MDL_context::acquire_lock(MDL_request *mdl_request, double lock_wait_timeout)
     switch (wait_status)
     {
     case MDL_wait::VICTIM:
-      mdl_dbug_print_locks();
+      DBUG_LOCK_FILE;
+      DBUG_PRINT("mdl_locks", ("%s", mdl_dbug_print_locks()));
+      DBUG_UNLOCK_FILE;
       my_error(ER_LOCK_DEADLOCK, MYF(0));
       break;
     case MDL_wait::TIMEOUT:
@@ -3241,34 +3272,3 @@ void MDL_ticket::wsrep_report(bool debug)
               psi_stage->m_name);
 }
 #endif /* WITH_WSREP */
-
-
-#ifndef DBUG_OFF
-
-/*
-  Print a list of all locks to DBUG trace to help with debugging
-*/
-
-static int mdl_dbug_print_lock(MDL_ticket *mdl_ticket, void *arg, bool granted)
-{
-  String *tmp= (String*) arg;
-  char buffer[128];
-  MDL_key *mdl_key= mdl_ticket->get_key();
-  size_t length;
-  length= my_snprintf(buffer, sizeof(buffer)-1,
-                      "\nname: %s  db: %.*s  key_name: %.*s (%s)",
-                      mdl_ticket->get_type_name()->str,
-                      (int) mdl_key->db_name_length(), mdl_key->db_name(),
-                      (int) mdl_key->name_length(),    mdl_key->name(),
-                      granted ? "granted" : "waiting");
-  tmp->append(buffer, length);
-  return 0;
-}
-
-void mdl_dbug_print_locks()
-{
-  String tmp;
-  mdl_iterate(mdl_dbug_print_lock, (void*) &tmp);
-  DBUG_PRINT("mdl_locks", ("%s", tmp.c_ptr()));
-}
-#endif /* DBUG_OFF */

sql/mdl.h

@@ -1106,9 +1106,4 @@ typedef int (*mdl_iterator_callback)(MDL_ticket *ticket, void *arg,
                                      bool granted);
 extern MYSQL_PLUGIN_IMPORT
 int mdl_iterate(mdl_iterator_callback callback, void *arg);
-#ifndef DBUG_OFF
-void mdl_dbug_print_locks();
-#else
-  static inline void mdl_dbug_print_locks() {}
-#endif /* DBUG_OFF */
 #endif /* MDL_H */