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| author | Sergei Golubchik <serg@mariadb.org> | 2021-01-07 19:37:47 +0100 |
|---|---|---|
| committer | Sergei Golubchik <serg@mariadb.org> | 2021-01-11 21:54:47 +0100 |
| commit | 63f91927870b41b8965e2a2a868abcc2b3672f68 (patch) | |
| tree | c1f7e0f76168834f2aa0ee461a9ce1e07bed0408 /sql/sql_show.cc | |
| parent | 4c448836d489bd5a25c7509e8a69309c3b0a8e72 (diff) | |
| download | mariadb-git-63f91927870b41b8965e2a2a868abcc2b3672f68.tar.gz | |
MDEV-17251 SHOW STATUS unnecessary calls calc_sum_of_all_status
1. only call calc_sum_of_all_status() if a global
SHOW_xxx_STATUS variable is to be returned
2. only lock LOCK_status when copying global_status_var,
but not when iterating all threads
Diffstat (limited to 'sql/sql_show.cc')
| -rw-r--r-- | sql/sql_show.cc | 20 |
1 files changed, 11 insertions, 9 deletions
diff --git a/sql/sql_show.cc b/sql/sql_show.cc index 79897429a4f..4294157cce3 100644 --- a/sql/sql_show.cc +++ b/sql/sql_show.cc @@ -3580,6 +3580,16 @@ static bool show_status_array(THD *thd, const char *wild, if (show_type == SHOW_SYS) mysql_mutex_lock(&LOCK_global_system_variables); + else if (show_type >= SHOW_LONG_STATUS && scope == OPT_GLOBAL && + !status_var->local_memory_used) + { + mysql_mutex_lock(&LOCK_status); + *status_var= global_status_var; + mysql_mutex_unlock(&LOCK_status); + calc_sum_of_all_status(status_var); + DBUG_ASSERT(status_var->local_memory_used); + } + pos= get_one_variable(thd, var, scope, show_type, status_var, &charset, buff, &length); @@ -3620,8 +3630,6 @@ uint calc_sum_of_all_status(STATUS_VAR *to) I_List_iterator<THD> it(threads); THD *tmp; - /* Get global values as base */ - *to= global_status_var; to->local_memory_used= 0; /* Add to this status from existing threads */ @@ -7586,13 +7594,7 @@ int fill_status(THD *thd, TABLE_LIST *tables, COND *cond) if (partial_cond) partial_cond->val_int(); - 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); - } + tmp.local_memory_used= 0; // meaning tmp was not populated yet mysql_mutex_lock(&LOCK_show_status); res= show_status_array(thd, wild, |