force stats recalculation when "show table status" is called

Summary:
Make innodb_stats_on_metadata a session variable and enforced for both
transient and persistent stats.

Test Plan: added a new test: innodb.innodb_table_status_stats

Reviewers: over

Reviewed By: over

mysql-test/suite/innodb/r/innodb_table_status_stats.result

@@ -0,0 +1,18 @@
+DROP TABLE if exists t1;
+# Create & populate table.
+CREATE TABLE t1 (a INT NOT NULL PRIMARY KEY AUTO_INCREMENT, b VARCHAR(256)) ENGINE=INNODB;
+# Force a stats update because normal stats calculation is done in background with separate thread
+# thus unpredictable.
+analyze table t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	OK
+pass
+1
+# The table currently have 128 records, adding another 10 will not trigger stats recalculation by default (< 10%).
+# Querying the stats should not trigger a stats recalculation by default.
+pass
+1
+# Querying the stats should trigger a stats recalculation when innod_stats_on_metadata is enabled.
+pass
+1
+drop table t1;

mysql-test/suite/innodb/t/innodb_table_status_stats.test

@@ -0,0 +1,52 @@
+--source include/have_innodb.inc
+--source include/have_innodb_16k.inc
+
+--disable_warnings
+DROP TABLE if exists t1;
+--enable_warnings
+
+--echo # Create & populate table.
+CREATE TABLE t1 (a INT NOT NULL PRIMARY KEY AUTO_INCREMENT, b VARCHAR(256)) ENGINE=INNODB;
+
+--disable_query_log
+INSERT INTO t1 VALUES (1, REPEAT('A', 256));
+INSERT INTO t1 (b) SELECT b from t1;
+INSERT INTO t1 (b) SELECT b from t1;
+INSERT INTO t1 (b) SELECT b from t1;
+INSERT INTO t1 (b) SELECT b from t1;
+INSERT INTO t1 (b) SELECT b from t1;
+INSERT INTO t1 (b) SELECT b from t1;
+INSERT INTO t1 (b) SELECT b from t1;
+--enable_query_log
+
+--echo # Force a stats update because normal stats calculation is done in background with separate thread
+--echo # thus unpredictable.
+analyze table t1;
+
+--disable_query_log
+--let $page_count = query_get_value(select count(*) as result from information_schema.innodb_buffer_page where table_name like '%t1%' and access_time > 0, result, 1)
+--let $data_length = query_get_value(select data_length from information_schema.tables where table_name='t1', data_length, 1)
+--eval select $page_count * 16384 = $data_length as pass
+
+--echo # The table currently have 128 records, adding another 10 will not trigger stats recalculation by default (< 10%).
+let $count=10;
+while ($count) {
+  INSERT INTO t1 (b) VALUES (REPEAT('A', 256));
+  dec $count;
+}
+
+--let $page_count = query_get_value(select count(*) as result from information_schema.innodb_buffer_page where table_name like '%t1%' and access_time > 0, result, 1)
+--let $data_length = query_get_value(select data_length from information_schema.tables where table_name='t1', data_length, 1)
+--echo # Querying the stats should not trigger a stats recalculation by default.
+--eval select $page_count * 16384 != $data_length as pass
+
+set session innodb_stats_on_metadata = on;
+--let $page_count = query_get_value(select count(*) as result from information_schema.innodb_buffer_page where table_name like '%t1%' and access_time > 0, result, 1)
+--let $data_length = query_get_value(select data_length from information_schema.tables where table_name='t1', data_length, 1)
+--echo # Querying the stats should trigger a stats recalculation when innod_stats_on_metadata is enabled.
+--eval select $page_count * 16384 = $data_length as pass
+
+--enable_query_log
+
+# Clean up
+drop table t1;

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

@@ -39,8 +39,6 @@ ERROR HY000: Variable 'innodb_file_format_check' is a read only variable
 Expected error 'Read only variable'
 SET session innodb_large_prefix='OFF';
 ERROR HY000: Variable 'innodb_large_prefix' is a GLOBAL variable and should be set with SET GLOBAL
-SET @@session.innodb_stats_on_metadata='ON';
-ERROR HY000: Variable 'innodb_stats_on_metadata' is a GLOBAL variable and should be set with SET GLOBAL
 SELECT IF(@@GLOBAL.innodb_file_format_check, "ON", "OFF") = VARIABLE_VALUE
 FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES
 WHERE VARIABLE_NAME='innodb_file_format_check';

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

@@ -10,7 +10,8 @@ select @@global.innodb_stats_on_metadata;
 @@global.innodb_stats_on_metadata
 0
 select @@session.innodb_stats_on_metadata;
-ERROR HY000: Variable 'innodb_stats_on_metadata' is a GLOBAL variable
+@@session.innodb_stats_on_metadata
+0
 show global variables like 'innodb_stats_on_metadata';
 Variable_name	Value
 innodb_stats_on_metadata	OFF
@@ -42,7 +43,7 @@ VARIABLE_NAME	VARIABLE_VALUE
 INNODB_STATS_ON_METADATA	ON
 select * from information_schema.session_variables where variable_name='innodb_stats_on_metadata';
 VARIABLE_NAME	VARIABLE_VALUE
-INNODB_STATS_ON_METADATA	ON
+INNODB_STATS_ON_METADATA	OFF
 set global innodb_stats_on_metadata=0;
 select @@global.innodb_stats_on_metadata;
 @@global.innodb_stats_on_metadata
@@ -62,11 +63,9 @@ VARIABLE_NAME	VARIABLE_VALUE
 INNODB_STATS_ON_METADATA	ON
 select * from information_schema.session_variables where variable_name='innodb_stats_on_metadata';
 VARIABLE_NAME	VARIABLE_VALUE
-INNODB_STATS_ON_METADATA	ON
+INNODB_STATS_ON_METADATA	OFF
 set session innodb_stats_on_metadata='OFF';
-ERROR HY000: Variable 'innodb_stats_on_metadata' is a GLOBAL variable and should be set with SET GLOBAL
 set @@session.innodb_stats_on_metadata='ON';
-ERROR HY000: Variable 'innodb_stats_on_metadata' is a GLOBAL variable and should be set with SET GLOBAL
 set global innodb_stats_on_metadata=1.1;
 ERROR 42000: Incorrect argument type to variable 'innodb_stats_on_metadata'
 set global innodb_stats_on_metadata=1e1;

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

@@ -46,8 +46,6 @@ SET @@global.innodb_file_format_check='On';
 
 --error ER_GLOBAL_VARIABLE
 SET session innodb_large_prefix='OFF';
---error ER_GLOBAL_VARIABLE
-SET @@session.innodb_stats_on_metadata='ON';
 
 #
 # Check if the value in GLOBAL Table matches value in variable 

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

@@ -14,7 +14,6 @@ SELECT @start_global_value;
 --echo Valid values are 'ON' and 'OFF' 
 select @@global.innodb_stats_on_metadata in (0, 1);
 select @@global.innodb_stats_on_metadata;
---error ER_INCORRECT_GLOBAL_LOCAL_VAR
 select @@session.innodb_stats_on_metadata;
 show global variables like 'innodb_stats_on_metadata';
 show session variables like 'innodb_stats_on_metadata';
@@ -40,9 +39,7 @@ set @@global.innodb_stats_on_metadata='ON';
 select @@global.innodb_stats_on_metadata;
 select * from information_schema.global_variables where variable_name='innodb_stats_on_metadata';
 select * from information_schema.session_variables where variable_name='innodb_stats_on_metadata';
---error ER_GLOBAL_VARIABLE
 set session innodb_stats_on_metadata='OFF';
---error ER_GLOBAL_VARIABLE
 set @@session.innodb_stats_on_metadata='ON';
 
 #

storage/innobase/handler/ha_innodb.cc

@@ -190,7 +190,6 @@ static my_bool	innobase_use_checksums			= TRUE;
 static my_bool	innobase_locks_unsafe_for_binlog	= FALSE;
 static my_bool	innobase_rollback_on_timeout		= FALSE;
 static my_bool	innobase_create_status_file		= FALSE;
-static my_bool	innobase_stats_on_metadata		= TRUE;
 static my_bool	innobase_large_prefix			= FALSE;
 static my_bool	innodb_optimize_fulltext_only		= FALSE;
 
@@ -599,6 +598,13 @@ static MYSQL_THDVAR_STR(tmpdir,
   "Directory for temporary files during DDL operations.",
   NULL, NULL, "");
 
+static MYSQL_THDVAR_BOOL(stats_on_metadata,
+  PLUGIN_VAR_OPCMDARG,
+  "Enable statistics gathering for metadata commands such as "
+  "SHOW TABLE STATUS for tables that use transient statistics or persistent "
+  "statistics. (OFF by default)",
+  NULL, NULL, FALSE);
+
 static SHOW_VAR innodb_status_variables[]= {
   {"adaptive_hash_hits",
   (char*) &export_vars.innodb_hash_searches,		  SHOW_LONG},
@@ -12000,7 +12006,8 @@ ha_innobase::info_low(
 	DBUG_ASSERT(ib_table->n_ref_count > 0);
 
 	if (flag & HA_STATUS_TIME) {
-		if (is_analyze || innobase_stats_on_metadata) {
+		bool stats_on_metadata = THDVAR(ha_thd(), stats_on_metadata);
+		if (is_analyze || stats_on_metadata) {
 
 			dict_stats_upd_option_t	opt;
 			dberr_t			ret;
@@ -12009,13 +12016,7 @@ ha_innobase::info_low(
 
 			if (dict_stats_is_persistent_enabled(ib_table)) {
 
-				if (is_analyze) {
-					opt = DICT_STATS_RECALC_PERSISTENT;
-				} else {
-					/* This is e.g. 'SHOW INDEXES', fetch
-					the persistent stats from disk. */
-					opt = DICT_STATS_FETCH_ONLY_IF_NOT_IN_MEMORY;
-				}
+				opt = DICT_STATS_RECALC_PERSISTENT;
 			} else {
 				opt = DICT_STATS_RECALC_TRANSIENT;
 			}
@@ -17529,12 +17530,6 @@ static MYSQL_SYSVAR_BOOL(status_file, innobase_create_status_file,
   "Enable SHOW ENGINE INNODB STATUS output in the innodb_status.<pid> file",
   NULL, NULL, FALSE);
 
-static MYSQL_SYSVAR_BOOL(stats_on_metadata, innobase_stats_on_metadata,
-  PLUGIN_VAR_OPCMDARG,
-  "Enable statistics gathering for metadata commands such as "
-  "SHOW TABLE STATUS for tables that use transient statistics (off by default)",
-  NULL, NULL, FALSE);
-
 static MYSQL_SYSVAR_ULONGLONG(stats_sample_pages, srv_stats_transient_sample_pages,
   PLUGIN_VAR_RQCMDARG,
   "Deprecated, use innodb_stats_transient_sample_pages instead",