MDEV-15135 - Make LOCK_show_status rwlock, to enable parallelism ofbb-10.4-lock-thread-count

fill_status.

Also, remove LOCK_status around calc_sum_of_all_status()

4 files changed, 19 insertions, 18 deletions

diff --git a/mysql-test/suite/perfschema/r/dml_setup_instruments.result b/mysql-test/suite/perfschema/r/dml_setup_instruments.result
index 307c5c5366a..c332763c4e3 100644
--- a/mysql-test/suite/perfschema/r/dml_setup_instruments.result
+++ b/mysql-test/suite/perfschema/r/dml_setup_instruments.result
@@ -22,13 +22,13 @@ NAME	ENABLED	TIMED
 wait/synch/rwlock/sql/LOCK_dboptions	YES	YES
 wait/synch/rwlock/sql/LOCK_grant	YES	YES
 wait/synch/rwlock/sql/LOCK_SEQUENCE	YES	YES
+wait/synch/rwlock/sql/LOCK_show_status	YES	YES
 wait/synch/rwlock/sql/LOCK_ssl_refresh	YES	YES
 wait/synch/rwlock/sql/LOCK_system_variables_hash	YES	YES
 wait/synch/rwlock/sql/LOCK_sys_init_connect	YES	YES
 wait/synch/rwlock/sql/LOCK_sys_init_slave	YES	YES
+wait/synch/rwlock/sql/LOCK_thread_count	YES	YES
 wait/synch/rwlock/sql/LOGGER::LOCK_logger	YES	YES
-wait/synch/rwlock/sql/MDL_context::LOCK_waiting_for	YES	YES
-wait/synch/rwlock/sql/MDL_lock::rwlock	YES	YES
 select * from performance_schema.setup_instruments
 where name like 'Wait/Synch/Cond/sql/%'
   and name not in (
diff --git a/sql/mysqld.cc b/sql/mysqld.cc
index faa48aaaecd..825c72d8674 100644
--- a/sql/mysqld.cc
+++ b/sql/mysqld.cc
@@ -743,13 +743,12 @@ mysql_mutex_t  LOCK_start_thread;
 
 mysql_mutex_t LOCK_thread_cache;
 mysql_mutex_t
-  LOCK_status, LOCK_show_status, LOCK_error_log, LOCK_short_uuid_generator,
+  LOCK_status, LOCK_error_log, LOCK_short_uuid_generator,
   LOCK_delayed_insert, LOCK_delayed_status, LOCK_delayed_create,
   LOCK_crypt,
   LOCK_global_system_variables,
   LOCK_user_conn, LOCK_slave_list,
   LOCK_connection_count, LOCK_error_messages, LOCK_slave_background;
-
 mysql_mutex_t LOCK_stats, LOCK_global_user_client_stats,
               LOCK_global_table_stats, LOCK_global_index_stats;
 
@@ -772,6 +771,7 @@ mysql_mutex_t LOCK_des_key_file;
 #endif
 mysql_rwlock_t LOCK_grant, LOCK_sys_init_connect, LOCK_sys_init_slave;
 mysql_rwlock_t LOCK_ssl_refresh;
+mysql_rwlock_t LOCK_show_status;
 mysql_prlock_t LOCK_system_variables_hash;
 mysql_cond_t COND_start_thread;
 pthread_t signal_thread;
@@ -1037,7 +1037,8 @@ PSI_rwlock_key key_rwlock_LOCK_grant, key_rwlock_LOCK_logger,
   key_LOCK_SEQUENCE,
   key_rwlock_LOCK_vers_stats, key_rwlock_LOCK_stat_serial,
   key_rwlock_LOCK_ssl_refresh,
-  key_rwlock_LOCK_thread_count;
+  key_rwlock_LOCK_thread_count,
+  key_rwlock_LOCK_show_status;
 
 static PSI_rwlock_info all_server_rwlocks[]=
 {
@@ -1053,7 +1054,9 @@ static PSI_rwlock_info all_server_rwlocks[]=
   { &key_rwlock_query_cache_query_lock, "Query_cache_query::lock", 0},
   { &key_rwlock_LOCK_vers_stats, "Vers_field_stats::lock", 0},
   { &key_rwlock_LOCK_stat_serial, "TABLE_SHARE::LOCK_stat_serial", 0},
-  { &key_rwlock_LOCK_ssl_refresh, "LOCK_ssl_refresh", PSI_FLAG_GLOBAL }
+  { &key_rwlock_LOCK_ssl_refresh, "LOCK_ssl_refresh", PSI_FLAG_GLOBAL },
+  { &key_rwlock_LOCK_show_status, "LOCK_show_status", PSI_FLAG_GLOBAL },
+  { &key_rwlock_LOCK_thread_count, "LOCK_thread_count", PSI_FLAG_GLOBAL },
 };
 
 #ifdef HAVE_MMAP
@@ -2249,7 +2252,7 @@ static void clean_up_mutexes()
   mysql_mutex_destroy(&LOCK_thread_cache);
   mysql_mutex_destroy(&LOCK_start_thread);
   mysql_mutex_destroy(&LOCK_status);
-  mysql_mutex_destroy(&LOCK_show_status);
+  mysql_rwlock_destroy(&LOCK_show_status);
   mysql_mutex_destroy(&LOCK_delayed_insert);
   mysql_mutex_destroy(&LOCK_delayed_status);
   mysql_mutex_destroy(&LOCK_delayed_create);
@@ -4600,7 +4603,6 @@ static int init_thread_environment()
   mysql_mutex_init(key_LOCK_thread_cache, &LOCK_thread_cache, MY_MUTEX_INIT_FAST);
   mysql_mutex_init(key_LOCK_start_thread, &LOCK_start_thread, MY_MUTEX_INIT_FAST);
   mysql_mutex_init(key_LOCK_status, &LOCK_status, MY_MUTEX_INIT_FAST);
-  mysql_mutex_init(key_LOCK_show_status, &LOCK_show_status, MY_MUTEX_INIT_SLOW);
   mysql_mutex_init(key_LOCK_delayed_insert,
                    &LOCK_delayed_insert, MY_MUTEX_INIT_FAST);
   mysql_mutex_init(key_LOCK_delayed_status,
@@ -4663,6 +4665,7 @@ static int init_thread_environment()
   mysql_rwlock_init(key_rwlock_LOCK_ssl_refresh, &LOCK_ssl_refresh);
   mysql_rwlock_init(key_rwlock_LOCK_grant, &LOCK_grant);
   mysql_rwlock_init(key_rwlock_LOCK_thread_count, &LOCK_thread_count);
+  mysql_rwlock_init(key_LOCK_show_status, &LOCK_show_status);
   mysql_cond_init(key_COND_thread_cache, &COND_thread_cache, NULL);
   mysql_cond_init(key_COND_start_thread, &COND_start_thread, NULL);
   mysql_cond_init(key_COND_flush_thread_cache, &COND_flush_thread_cache, NULL);
diff --git a/sql/mysqld.h b/sql/mysqld.h
index edbc22f1099..e15aa748cdc 100644
--- a/sql/mysqld.h
+++ b/sql/mysqld.h
@@ -621,7 +621,7 @@ extern MYSQL_PLUGIN_IMPORT key_map key_map_full;          /* Should be threaded
   Server mutex locks and condition variables.
  */
 extern mysql_mutex_t
-       LOCK_item_func_sleep, LOCK_status, LOCK_show_status,
+       LOCK_item_func_sleep, LOCK_status,
        LOCK_error_log, LOCK_delayed_insert, LOCK_short_uuid_generator,
        LOCK_delayed_status, LOCK_delayed_create, LOCK_crypt, LOCK_timezone,
        LOCK_slave_list, LOCK_active_mi, LOCK_manager,
@@ -629,6 +629,7 @@ extern mysql_mutex_t
        LOCK_prepared_stmt_count, LOCK_error_messages, LOCK_connection_count,
        LOCK_slave_background;
 extern MYSQL_PLUGIN_IMPORT mysql_rwlock_t LOCK_thread_count;
+extern mysql_rwlock_t LOCK_show_status;
 extern mysql_mutex_t LOCK_start_thread;
 #ifdef HAVE_OPENSSL
 extern char* des_key_file;
diff --git a/sql/sql_show.cc b/sql/sql_show.cc
index e7202da082c..8e3a7bd7c4a 100644
--- a/sql/sql_show.cc
+++ b/sql/sql_show.cc
@@ -3376,7 +3376,7 @@ int add_status_vars(SHOW_VAR *list)
 {
   int res= 0;
   if (status_vars_inited)
-    mysql_mutex_lock(&LOCK_show_status);
+    mysql_rwlock_wrlock(&LOCK_show_status);
   if (!all_status_vars.buffer && // array is not allocated yet - do it now
       my_init_dynamic_array(&all_status_vars, sizeof(SHOW_VAR), 250, 50, MYF(0)))
   {
@@ -3391,7 +3391,7 @@ int add_status_vars(SHOW_VAR *list)
     sort_dynamic(&all_status_vars, show_var_cmp);
 err:
   if (status_vars_inited)
-    mysql_mutex_unlock(&LOCK_show_status);
+    mysql_rwlock_unlock(&LOCK_show_status);
   return res;
 }
 
@@ -3453,7 +3453,7 @@ void remove_status_vars(SHOW_VAR *list)
 {
   if (status_vars_inited)
   {
-    mysql_mutex_lock(&LOCK_show_status);
+    mysql_rwlock_wrlock(&LOCK_show_status);
     SHOW_VAR *all= dynamic_element(&all_status_vars, 0, SHOW_VAR *);
 
     for (; list->name; list++)
@@ -3474,7 +3474,7 @@ void remove_status_vars(SHOW_VAR *list)
       }
     }
     shrink_var_array(&all_status_vars);
-    mysql_mutex_unlock(&LOCK_show_status);
+    mysql_rwlock_unlock(&LOCK_show_status);
   }
   else
   {
@@ -7826,18 +7826,15 @@ int fill_status(THD *thd, TABLE_LIST *tables, COND *cond)
 
   if (scope == OPT_GLOBAL)
   {
-    /* We only hold LOCK_status for summary status vars */
-    mysql_mutex_lock(&LOCK_status);
     calc_sum_of_all_status(&tmp);
-    mysql_mutex_unlock(&LOCK_status);
   }
 
-  mysql_mutex_lock(&LOCK_show_status);
+  mysql_rwlock_rdlock(&LOCK_show_status);
   res= show_status_array(thd, wild,
                          (SHOW_VAR *)all_status_vars.buffer,
                          scope, tmp1, "", tables->table,
                          upper_case_names, partial_cond);
-  mysql_mutex_unlock(&LOCK_show_status);
+  mysql_rwlock_unlock(&LOCK_show_status);
   DBUG_RETURN(res);
 }