MDEV-10296 - Multi-instance table cache

Improve scalability by implementing multi-instance table cache.

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

@@ -1091,6 +1091,8 @@ The following options may be given as the first argument:
  The number of cached table definitions
  --table-open-cache=# 
  The number of cached open tables
+ --table-open-cache-instances=# 
+ The number of table cache instances
  --tc-heuristic-recover=name 
  Decision to use in heuristic recover process. One of: OFF,
  COMMIT, ROLLBACK
@@ -1457,6 +1459,7 @@ sysdate-is-now FALSE
 table-cache 431
 table-definition-cache 400
 table-open-cache 431
+table-open-cache-instances 1
 tc-heuristic-recover OFF
 thread-cache-size 151
 thread-pool-idle-timeout 60

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

@@ -3887,6 +3887,20 @@ NUMERIC_BLOCK_SIZE	1
 ENUM_VALUE_LIST	NULL
 READ_ONLY	NO
 COMMAND_LINE_ARGUMENT	REQUIRED
+VARIABLE_NAME	TABLE_OPEN_CACHE_INSTANCES
+SESSION_VALUE	NULL
+GLOBAL_VALUE	1
+GLOBAL_VALUE_ORIGIN	COMPILE-TIME
+DEFAULT_VALUE	1
+VARIABLE_SCOPE	GLOBAL
+VARIABLE_TYPE	BIGINT UNSIGNED
+VARIABLE_COMMENT	The number of table cache instances
+NUMERIC_MIN_VALUE	1
+NUMERIC_MAX_VALUE	64
+NUMERIC_BLOCK_SIZE	1
+ENUM_VALUE_LIST	NULL
+READ_ONLY	YES
+COMMAND_LINE_ARGUMENT	REQUIRED
 VARIABLE_NAME	THREAD_CACHE_SIZE
 SESSION_VALUE	NULL
 GLOBAL_VALUE	151

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

@@ -4657,6 +4657,20 @@ NUMERIC_BLOCK_SIZE	1
 ENUM_VALUE_LIST	NULL
 READ_ONLY	NO
 COMMAND_LINE_ARGUMENT	REQUIRED
+VARIABLE_NAME	TABLE_OPEN_CACHE_INSTANCES
+SESSION_VALUE	NULL
+GLOBAL_VALUE	1
+GLOBAL_VALUE_ORIGIN	COMPILE-TIME
+DEFAULT_VALUE	1
+VARIABLE_SCOPE	GLOBAL
+VARIABLE_TYPE	BIGINT UNSIGNED
+VARIABLE_COMMENT	The number of table cache instances
+NUMERIC_MIN_VALUE	1
+NUMERIC_MAX_VALUE	64
+NUMERIC_BLOCK_SIZE	1
+ENUM_VALUE_LIST	NULL
+READ_ONLY	YES
+COMMAND_LINE_ARGUMENT	REQUIRED
 VARIABLE_NAME	THREAD_CACHE_SIZE
 SESSION_VALUE	NULL
 GLOBAL_VALUE	151

sql/mysqld.cc

@@ -4974,8 +4974,7 @@ static int init_server_components()
     all things are initialized so that unireg_abort() doesn't fail
   */
   mdl_init();
-  tdc_init();
-  if (hostname_cache_init())
+  if (tdc_init() || hostname_cache_init())
     unireg_abort(1);
 
   query_cache_set_min_res_unit(query_cache_min_res_unit);
@@ -7643,7 +7642,6 @@ struct my_option my_long_options[]=
   MYSQL_TO_BE_IMPLEMENTED_OPTION("eq-range-index-dive-limit"),
   MYSQL_COMPATIBILITY_OPTION("server-id-bits"),
   MYSQL_TO_BE_IMPLEMENTED_OPTION("slave-rows-search-algorithms"), // HAVE_REPLICATION
-  MYSQL_COMPATIBILITY_OPTION("table-open-cache-instances"),
   MYSQL_TO_BE_IMPLEMENTED_OPTION("slave-allow-batching"),         // HAVE_REPLICATION
   MYSQL_COMPATIBILITY_OPTION("slave-checkpoint-period"),      // HAVE_REPLICATION
   MYSQL_COMPATIBILITY_OPTION("slave-checkpoint-group"),       // HAVE_REPLICATION

sql/sql_base.cc

@@ -878,8 +878,7 @@ void close_thread_table(THD *thd, TABLE **table_ptr)
     Do this *before* entering the TABLE_SHARE::tdc.LOCK_table_share
     critical section.
   */
-  if (table->file != NULL)
-    MYSQL_UNBIND_TABLE(table->file);
+  MYSQL_UNBIND_TABLE(table->file);
 
   tc_release_table(table);
   DBUG_VOID_RETURN;

sql/sys_vars.cc

@@ -3227,6 +3227,11 @@ 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(
+       "table_open_cache_instances", "The number of table cache instances",
+       READ_ONLY GLOBAL_VAR(tc_instances), CMD_LINE(REQUIRED_ARG),
+       VALID_RANGE(1, 64), DEFAULT(1), BLOCK_SIZE(1));
+
 static Sys_var_ulong Sys_thread_cache_size(
        "thread_cache_size",
        "How many threads we should keep in a cache for reuse. These are freed after 5 minutes of idle time",

sql/table.h

@@ -1021,13 +1021,13 @@ struct TABLE
      One should use methods of I_P_List template instead.
   */
   TABLE *share_all_next, **share_all_prev;
+  TABLE *global_free_next, **global_free_prev;
   friend struct All_share_tables;
+  friend class Table_cache_instance;
 
 public:
 
   THD	*in_use;                        /* Which thread uses this */
-  /* Time when table was released to table cache. Valid for unused tables. */
-  ulonglong tc_time;
   Field **field;			/* Pointer to fields */
 
   uchar *record[2];			/* Pointer to records */

sql/table_cache.h

@@ -18,6 +18,15 @@
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */
 
 
+struct Share_free_tables
+{
+  typedef I_P_List <TABLE, TABLE_share> List;
+  List list;
+  /** Avoid false sharing between instances */
+  char pad[CPU_LEVEL1_DCACHE_LINESIZE];
+};
+
+
 struct TDC_element
 {
   uchar m_key[NAME_LEN + 1 + NAME_LEN + 1];
@@ -26,10 +35,8 @@ struct TDC_element
   bool flushed;
   TABLE_SHARE *share;
 
-  typedef I_P_List <TABLE, TABLE_share> TABLE_list;
   /**
-    Protects ref_count, m_flush_tickets, all_tables, free_tables, flushed,
-    all_tables_refs.
+    Protects ref_count, m_flush_tickets, all_tables, flushed, all_tables_refs.
   */
   mysql_mutex_t LOCK_table_share;
   mysql_cond_t COND_release;
@@ -45,7 +52,9 @@ struct TDC_element
     for this share.
   */
   All_share_tables_list all_tables;
-  TABLE_list free_tables;
+  /** Avoid false sharing between TDC_element and free_tables */
+  char pad[CPU_LEVEL1_DCACHE_LINESIZE];
+  Share_free_tables free_tables[1];
 };
 
 
@@ -59,8 +68,9 @@ enum enum_tdc_remove_table_type
 
 extern ulong tdc_size;
 extern ulong tc_size;
+extern ulong tc_instances;
 
-extern void tdc_init(void);
+extern bool tdc_init(void);
 extern void tdc_start_shutdown(void);
 extern void tdc_deinit(void);
 extern ulong tdc_records(void);
@@ -86,7 +96,7 @@ extern int tdc_iterate(THD *thd, my_hash_walk_action action, void *argument,
 extern uint tc_records(void);
 extern void tc_purge(bool mark_flushed= false);
 extern void tc_add_table(THD *thd, TABLE *table);
-extern bool tc_release_table(TABLE *table);
+extern void tc_release_table(TABLE *table);
 
 /**
   Create a table cache key for non-temporary table.