Allow fixed table_open_cache_instances

Introduced table_open_cache_instances_fix variable. It activates all
table_open_cache_instances early. Can be useful for cases when table
cache warm up period is undesired. Such as benchmarking.

Author: svoj

mysql-test/main/mysqld--help.result

@@ -1549,6 +1549,10 @@ The following specify which files/extra groups are read (specified before remain
  The number of cached open tables
  --table-open-cache-instances=# 
  Maximum number of table cache instances
+ --table-open-cache-instances-fix 
+ Activate all table_open_cache_instances early. Can be
+ useful for cases when table cache warm up period is
+ undesired. Such as benchmarking
  --tc-heuristic-recover=name 
  Decision to use in heuristic recover process. One of: OFF,
  COMMIT, ROLLBACK
@@ -2055,6 +2059,7 @@ sysdate-is-now FALSE
 system-versioning-alter-history ERROR
 system-versioning-insert-history FALSE
 table-definition-cache 400
+table-open-cache-instances-fix FALSE
 tc-heuristic-recover OFF
 tcp-keepalive-interval 0
 tcp-keepalive-probes 0

mysql-test/suite/sys_vars/r/sysvars_server_embedded.result

@@ -3942,6 +3942,16 @@ NUMERIC_BLOCK_SIZE	1
 ENUM_VALUE_LIST	NULL
 READ_ONLY	YES
 COMMAND_LINE_ARGUMENT	REQUIRED
+VARIABLE_NAME	TABLE_OPEN_CACHE_INSTANCES_FIX
+VARIABLE_SCOPE	GLOBAL
+VARIABLE_TYPE	BOOLEAN
+VARIABLE_COMMENT	Activate all table_open_cache_instances early. Can be useful for cases when table cache warm up period is undesired. Such as benchmarking
+NUMERIC_MIN_VALUE	NULL
+NUMERIC_MAX_VALUE	NULL
+NUMERIC_BLOCK_SIZE	NULL
+ENUM_VALUE_LIST	OFF,ON
+READ_ONLY	YES
+COMMAND_LINE_ARGUMENT	OPTIONAL
 VARIABLE_NAME	TCP_KEEPALIVE_INTERVAL
 VARIABLE_SCOPE	GLOBAL
 VARIABLE_TYPE	INT

mysql-test/suite/sys_vars/r/sysvars_server_notembedded.result

@@ -4722,6 +4722,16 @@ NUMERIC_BLOCK_SIZE	1
 ENUM_VALUE_LIST	NULL
 READ_ONLY	YES
 COMMAND_LINE_ARGUMENT	REQUIRED
+VARIABLE_NAME	TABLE_OPEN_CACHE_INSTANCES_FIX
+VARIABLE_SCOPE	GLOBAL
+VARIABLE_TYPE	BOOLEAN
+VARIABLE_COMMENT	Activate all table_open_cache_instances early. Can be useful for cases when table cache warm up period is undesired. Such as benchmarking
+NUMERIC_MIN_VALUE	NULL
+NUMERIC_MAX_VALUE	NULL
+NUMERIC_BLOCK_SIZE	NULL
+ENUM_VALUE_LIST	OFF,ON
+READ_ONLY	YES
+COMMAND_LINE_ARGUMENT	OPTIONAL
 VARIABLE_NAME	TCP_KEEPALIVE_INTERVAL
 VARIABLE_SCOPE	GLOBAL
 VARIABLE_TYPE	INT

mysql-test/suite/sys_vars/r/table_open_cache_instances_fix.result

@@ -0,0 +1,9 @@
+SHOW VARIABLES LIKE 'table_open_cache_instances_fix';
+Variable_name	Value
+table_open_cache_instances_fix	ON
+SHOW VARIABLES LIKE 'table_open_cache_instances';
+Variable_name	Value
+table_open_cache_instances	4
+SHOW STATUS LIKE 'table_open_cache_active_instances';
+Variable_name	Value
+Table_open_cache_active_instances	4

mysql-test/suite/sys_vars/t/table_open_cache_instances_fix.opt

@@ -0,0 +1 @@
+--table-open-cache-instances-fix --table-open-cache=100 --table-open-cache-instances=4

mysql-test/suite/sys_vars/t/table_open_cache_instances_fix.test

@@ -0,0 +1,3 @@
+SHOW VARIABLES LIKE 'table_open_cache_instances_fix';
+SHOW VARIABLES LIKE 'table_open_cache_instances';
+SHOW STATUS LIKE 'table_open_cache_active_instances';

sql/sys_vars.cc

@@ -4299,6 +4299,14 @@ static Sys_var_ulong Sys_table_cache_size(
        BLOCK_SIZE(1), NO_MUTEX_GUARD, NOT_IN_BINLOG, ON_CHECK(0),
        ON_UPDATE(fix_table_open_cache));
 
+static Sys_var_mybool Sys_table_cache_instances_fix(
+       "table_open_cache_instances_fix",
+       "Activate all table_open_cache_instances early. Can be useful for "
+       "cases when table cache warm up period is undesired. Such as "
+       "benchmarking",
+       READ_ONLY GLOBAL_VAR(tc_instances_fix), CMD_LINE(OPT_ARG),
+       DEFAULT(FALSE));
+
 static Sys_var_uint Sys_table_cache_instances(
        "table_open_cache_instances", "Maximum number of table cache instances",
        READ_ONLY GLOBAL_VAR(tc_instances), CMD_LINE(REQUIRED_ARG),

sql/table_cache.cc

@@ -71,6 +71,7 @@ I_P_List <TDC_element,
           I_P_List_fast_push_back<TDC_element> > unused_shares;
 
 static bool tdc_inited;
+my_bool tc_instances_fix;
 
 
 /**
@@ -612,6 +613,8 @@ bool tdc_init(void)
     DBUG_RETURN(true);
   tc_allocated_size= (tc_instances + 1) * sizeof *tc;
   update_malloc_size(tc_allocated_size, 0);
+  if (tc_instances_fix)
+    tc_active_instances.store(tc_instances, std::memory_order_relaxed);
   tdc_inited= true;
   mysql_mutex_init(key_LOCK_unused_shares, &LOCK_unused_shares,
                    MY_MUTEX_INIT_FAST);

sql/table_cache.h

@@ -64,6 +64,7 @@ struct TDC_element
 extern ulong tdc_size;
 extern ulong tc_size;
 extern uint32 tc_instances;
+extern my_bool tc_instances_fix;
 
 extern bool tdc_init(void);
 extern void tdc_start_shutdown(void);