MDEV-10296 - Multi-instance table cache

Fixed sysvars_server_[not]embedded failure: changed type of
table_open_cache_instances from ulong to uint.

Added casts foratomic operations around tc_active_instances and
tc_contention_warning_reported: needed on some platforms.

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

@@ -3893,7 +3893,7 @@ GLOBAL_VALUE	8
 GLOBAL_VALUE_ORIGIN	COMPILE-TIME
 DEFAULT_VALUE	8
 VARIABLE_SCOPE	GLOBAL
-VARIABLE_TYPE	BIGINT UNSIGNED
+VARIABLE_TYPE	INT UNSIGNED
 VARIABLE_COMMENT	Maximum number of table cache instances
 NUMERIC_MIN_VALUE	1
 NUMERIC_MAX_VALUE	64

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

@@ -4663,7 +4663,7 @@ GLOBAL_VALUE	8
 GLOBAL_VALUE_ORIGIN	COMPILE-TIME
 DEFAULT_VALUE	8
 VARIABLE_SCOPE	GLOBAL
-VARIABLE_TYPE	BIGINT UNSIGNED
+VARIABLE_TYPE	INT UNSIGNED
 VARIABLE_COMMENT	Maximum number of table cache instances
 NUMERIC_MIN_VALUE	1
 NUMERIC_MAX_VALUE	64

sql/sys_vars.cc

@@ -3227,7 +3227,7 @@ 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_ulong Sys_table_cache_instances(
+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),
        VALID_RANGE(1, 64), DEFAULT(8), BLOCK_SIZE(1));

sql/table_cache.cc

@@ -55,7 +55,7 @@
 /** Configuration. */
 ulong tdc_size; /**< Table definition cache threshold for LRU eviction. */
 ulong tc_size; /**< Table cache threshold for LRU eviction. */
-ulong tc_instances;
+uint32 tc_instances;
 static uint32 tc_active_instances= 1;
 static uint32 tc_contention_warning_reported;
 
@@ -172,8 +172,9 @@ struct Table_cache_instance
       {
         if (n_instances < tc_instances)
         {
-          if (my_atomic_cas32_weak_explicit(&tc_active_instances, &n_instances,
-                                            n_instances + 1,
+          if (my_atomic_cas32_weak_explicit((int32*) &tc_active_instances,
+                                            (int32*) &n_instances,
+                                            (int32) n_instances + 1,
                                             MY_MEMORY_ORDER_RELAXED,
                                             MY_MEMORY_ORDER_RELAXED))
           {
@@ -186,8 +187,8 @@ struct Table_cache_instance
                                   n_instances + 1);
           }
         }
-        else if (!my_atomic_fas32_explicit(&tc_contention_warning_reported, 1,
-                                           MY_MEMORY_ORDER_RELAXED))
+        else if (!my_atomic_fas32_explicit((int32) &tc_contention_warning_reported,
+                                           1, MY_MEMORY_ORDER_RELAXED))
         {
           sql_print_warning("Detected table cache mutex contention at instance %d: "
                             "%d%% waits. Additional table cache instance "
@@ -353,7 +354,8 @@ void tc_purge(bool mark_flushed)
 
 void tc_add_table(THD *thd, TABLE *table)
 {
-  uint32 i= thd->thread_id % my_atomic_load32_explicit(&tc_active_instances, MY_MEMORY_ORDER_RELAXED);
+  uint32 i= thd->thread_id % my_atomic_load32_explicit((int32*) &tc_active_instances,
+                                                       MY_MEMORY_ORDER_RELAXED);
   TABLE *LRU_table= 0;
   TDC_element *element= table->s->tdc;
 
@@ -395,7 +397,8 @@ void tc_add_table(THD *thd, TABLE *table)
 static TABLE *tc_acquire_table(THD *thd, TDC_element *element)
 {
   uint32 n_instances=
-    my_atomic_load32_explicit(&tc_active_instances, MY_MEMORY_ORDER_RELAXED);
+    my_atomic_load32_explicit((int32*) &tc_active_instances,
+                              MY_MEMORY_ORDER_RELAXED);
   uint32 i= thd->thread_id % n_instances;
   TABLE *table;
 

sql/table_cache.h

@@ -68,7 +68,7 @@ enum enum_tdc_remove_table_type
 
 extern ulong tdc_size;
 extern ulong tc_size;
-extern ulong tc_instances;
+extern uint32 tc_instances;
 
 extern bool tdc_init(void);
 extern void tdc_start_shutdown(void);