Table_locks_waited

Table_locks_immediate

mysql-test/r/status.result

+Variable_name	Value
+Table_locks_immediate	5
+Table_locks_waited	0
+Variable_name	Value
+Table_locks_immediate	8
+Table_locks_waited	1

mysql-test/t/status.test

+connect (con1,localhost,root,,test,0,mysql-master.sock);
+connect (con2,localhost,root,,test,0,mysql-master.sock);
+
+#don't polute binlog
+show status like 'Table_lock%';
+connection con1;
+SET SQL_LOG_BIN=0;
+drop table if exists t1;
+create table t1(n int);
+insert into t1 values(1);
+connection con2;
+lock tables t1 read;
+unlock tables;
+lock tables t1 read;
+connection con1;
+send update t1 set n = 3;
+connection con2;
+sleep 0.5;
+unlock tables;
+connection con1;
+reap;
+show status like 'Table_lock%';
+

mysys/thr_lock.c

@@ -83,7 +83,7 @@ multiple read locks.
 #include <errno.h>
 
 my_bool thr_lock_inited=0;
-
+ulong locks_immediate = 0L, locks_waited = 0L;
 
 /* The following constants are only for debug output */
 #define MAX_THREADS 100
@@ -387,6 +387,7 @@ static my_bool wait_for_lock(struct st_lock_list *wait, THR_LOCK_DATA *data,
   else
   {
     result=0;
+    ++locks_waited;
     if (data->lock->get_status)
       (*data->lock->get_status)(data->status_param);
     check_locks(data->lock,"got wait_for_lock",0);
@@ -447,6 +448,7 @@ int thr_lock(THR_LOCK_DATA *data,enum thr_lock_type lock_type)
 	check_locks(lock,"read lock with old write lock",0);
 	if (lock->get_status)
 	  (*lock->get_status)(data->status_param);
+	++locks_immediate;
 	goto end;
       }
       if (lock->write.data->type == TL_WRITE_ONLY)
@@ -470,6 +472,7 @@ int thr_lock(THR_LOCK_DATA *data,enum thr_lock_type lock_type)
       if ((int) lock_type == (int) TL_READ_NO_INSERT)
 	lock->read_no_write_count++;
       check_locks(lock,"read lock with no write locks",0);
+      ++locks_immediate;
       goto end;
     }
     /* Can't get lock yet;  Wait for it */
@@ -501,6 +504,7 @@ int thr_lock(THR_LOCK_DATA *data,enum thr_lock_type lock_type)
 	data->cond=get_cond();
 	if (lock->get_status)
 	  (*lock->get_status)(data->status_param);
+	++locks_immediate;
 	goto end;
       }
     }
@@ -535,6 +539,7 @@ int thr_lock(THR_LOCK_DATA *data,enum thr_lock_type lock_type)
 	check_locks(lock,"second write lock",0);
 	if (data->lock->get_status)
 	  (*data->lock->get_status)(data->status_param);
+	++locks_immediate;
 	goto end;
       }
       DBUG_PRINT("lock",("write locked by thread: %ld",
@@ -560,6 +565,7 @@ int thr_lock(THR_LOCK_DATA *data,enum thr_lock_type lock_type)
 	  if (data->lock->get_status)
 	    (*data->lock->get_status)(data->status_param);
 	  check_locks(lock,"only write lock",0);
+	  ++locks_immediate;
 	  goto end;
 	}
       }

sql/mysqld.cc

@@ -260,6 +260,7 @@ ulong query_id=1L,long_query_count,long_query_time,aborted_threads,
       delayed_queue_size,delayed_insert_threads,delayed_insert_writes,
       delayed_rows_in_use,delayed_insert_errors,flush_time, thread_created;
 ulong filesort_rows, filesort_range_count, filesort_scan_count;
+extern "C" ulong locks_immediate, locks_waited;
 ulong filesort_merge_passes;
 ulong select_range_check_count, select_range_count, select_scan_count;
 ulong select_full_range_join_count,select_full_join_count;
@@ -2804,6 +2805,8 @@ struct show_var_st status_vars[]= {
   {"Sort_range",	       (char*) &filesort_range_count,   SHOW_LONG},
   {"Sort_rows",		       (char*) &filesort_rows,	        SHOW_LONG},
   {"Sort_scan",		       (char*) &filesort_scan_count,    SHOW_LONG},
+  {"Table_locks_immediate",    (char*) &locks_immediate,        SHOW_LONG},
+  {"Table_locks_waited",       (char*) &locks_waited,           SHOW_LONG},
   {"Threads_cached",           (char*) &cached_thread_count,    SHOW_LONG_CONST},
   {"Threads_created",	       (char*) &thread_created,		SHOW_LONG_CONST},
   {"Threads_connected",        (char*) &thread_count,           SHOW_INT_CONST},

sql/sql_base.cc

@@ -32,6 +32,7 @@
 TABLE *unused_tables;				/* Used by mysql_test */
 HASH open_cache;				/* Used by mysql_test */
 
+extern "C" ulong locks_waited, locks_immediate;
 
 static int open_unireg_entry(THD *thd,TABLE *entry,const char *db,
 			     const char *name, const char *alias, bool locked);
@@ -1166,7 +1167,8 @@ bool wait_for_tables(THD *thd)
   {
     /* Now we can open all tables without any interference */
     thd->proc_info="Reopen tables";
-    result=reopen_tables(thd,0,0);
+    if(!(result=reopen_tables(thd,0,0)))
+       ++locks_waited;
   }
   pthread_mutex_unlock(&LOCK_open);
   thd->proc_info=0;