MDEV-7084: innodb index stats inadequate using constant

innodb_stats_sample_pages

Analysis: If you set the number of analyzed pages 
to very low number compared to actual pages on 
that table/index it randomly pics those pages 
(default 8 pages), this leads to fact that query 
after analyze table returns different results. If 
the index tree is small, smaller than 10 * 
n_sample_pages + total_external_size, then the 
estimate is ok. For bigger index trees it is 
common that we do not see any borders between 
key values in the few pages we pick. But still 
there may be n_sample_pages different key values, 
or even more. And it just tries to 
approximate to n_sample_pages (8).

Fix: (1) Introduced new dynamic configuration variable
innodb_stats_sample_traditional  that retains
the current design. Default false.

(2) If traditional sample is not used we use
n_sample_pages = max(min(srv_stats_sample_pages,
                         index->stat_index_size),
                     log2(index->stat_index_size)*
                          srv_stats_sample_pages);

(3) Introduced new dynamic configuration variable
stat_modified_counter (default = 0) if set
sets lower bound for row updates when statistics is re-estimated.

If user has provided upper bound for how many rows needs to be updated
before we calculate new statistics we use minimum of provided value
and 1/16 of table every 16th round. If no upper bound is provided
(srv_stats_modified_counter = 0, default) then calculate new statistics
if 1 / 16 of table has been modified
since the last time a statistics batch was run.
We calculate statistics at most every 16th round, since we may have
a counter table which is very small and updated very often.
@param t table
@return true if the table has changed too much and stats need to be
recalculated
*/
#define DICT_TABLE_CHANGED_TOO_MUCH(t) \
	((ib_int64_t) (t)->stat_modified_counter > (srv_stats_modified_counter ? \
	ut_min(srv_stats_modified_counter, (16 + (t)->stat_n_rows / 16)) : \
		16 + (t)->stat_n_rows / 16))

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

+SET @start_global_value = @@global.innodb_stats_modified_counter;
+SELECT @start_global_value;
+@start_global_value
+0
+Valid values are one or above
+select @@global.innodb_stats_modified_counter >=1;
+@@global.innodb_stats_modified_counter >=1
+0
+select @@global.innodb_stats_modified_counter;
+@@global.innodb_stats_modified_counter
+0
+select @@session.innodb_stats_modified_counter;
+ERROR HY000: Variable 'innodb_stats_modified_counter' is a GLOBAL variable
+show global variables like 'innodb_stats_modified_counter';
+Variable_name	Value
+innodb_stats_modified_counter	0
+show session variables like 'innodb_stats_modified_counter';
+Variable_name	Value
+innodb_stats_modified_counter	0
+select * from information_schema.global_variables where variable_name='innodb_stats_modified_counter';
+VARIABLE_NAME	VARIABLE_VALUE
+INNODB_STATS_MODIFIED_COUNTER	0
+select * from information_schema.session_variables where variable_name='innodb_stats_modified_counter';
+VARIABLE_NAME	VARIABLE_VALUE
+INNODB_STATS_MODIFIED_COUNTER	0
+set global innodb_stats_modified_counter=10;
+select @@global.innodb_stats_modified_counter;
+@@global.innodb_stats_modified_counter
+10
+select * from information_schema.global_variables where variable_name='innodb_stats_modified_counter';
+VARIABLE_NAME	VARIABLE_VALUE
+INNODB_STATS_MODIFIED_COUNTER	10
+select * from information_schema.session_variables where variable_name='innodb_stats_modified_counter';
+VARIABLE_NAME	VARIABLE_VALUE
+INNODB_STATS_MODIFIED_COUNTER	10
+set session innodb_stats_modified_counter=1;
+ERROR HY000: Variable 'innodb_stats_modified_counter' is a GLOBAL variable and should be set with SET GLOBAL
+set global innodb_stats_modified_counter=1.1;
+ERROR 42000: Incorrect argument type to variable 'innodb_stats_modified_counter'
+set global innodb_stats_modified_counter=1e1;
+ERROR 42000: Incorrect argument type to variable 'innodb_stats_modified_counter'
+set global innodb_stats_modified_counter="foo";
+ERROR 42000: Incorrect argument type to variable 'innodb_stats_modified_counter'
+set global innodb_stats_modified_counter=-7;
+Warnings:
+Warning	1292	Truncated incorrect innodb_stats_modified_counter value: '-7'
+select @@global.innodb_stats_modified_counter;
+@@global.innodb_stats_modified_counter
+0
+select * from information_schema.global_variables where variable_name='innodb_stats_modified_counter';
+VARIABLE_NAME	VARIABLE_VALUE
+INNODB_STATS_MODIFIED_COUNTER	0
+SET @@global.innodb_stats_modified_counter = @start_global_value;
+SELECT @@global.innodb_stats_modified_counter;
+@@global.innodb_stats_modified_counter
+0

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

+SET @start_global_value = @@global.innodb_stats_traditional;
+SELECT @start_global_value;
+@start_global_value
+0
+Valid values are 'ON' and 'OFF' 
+select @@global.innodb_stats_traditional in (0, 1);
+@@global.innodb_stats_traditional in (0, 1)
+1
+select @@global.innodb_stats_traditional;
+@@global.innodb_stats_traditional
+0
+select @@session.innodb_stats_traditional;
+ERROR HY000: Variable 'innodb_stats_traditional' is a GLOBAL variable
+show global variables like 'innodb_stats_traditional';
+Variable_name	Value
+innodb_stats_traditional	OFF
+show session variables like 'innodb_stats_traditional';
+Variable_name	Value
+innodb_stats_traditional	OFF
+select * from information_schema.global_variables where variable_name='innodb_stats_traditional';
+VARIABLE_NAME	VARIABLE_VALUE
+INNODB_STATS_TRADITIONAL	OFF
+select * from information_schema.session_variables where variable_name='innodb_stats_traditional';
+VARIABLE_NAME	VARIABLE_VALUE
+INNODB_STATS_TRADITIONAL	OFF
+set global innodb_stats_traditional='OFF';
+select @@global.innodb_stats_traditional;
+@@global.innodb_stats_traditional
+0
+select * from information_schema.global_variables where variable_name='innodb_stats_traditional';
+VARIABLE_NAME	VARIABLE_VALUE
+INNODB_STATS_TRADITIONAL	OFF
+select * from information_schema.session_variables where variable_name='innodb_stats_traditional';
+VARIABLE_NAME	VARIABLE_VALUE
+INNODB_STATS_TRADITIONAL	OFF
+set @@global.innodb_stats_traditional=1;
+select @@global.innodb_stats_traditional;
+@@global.innodb_stats_traditional
+1
+select * from information_schema.global_variables where variable_name='innodb_stats_traditional';
+VARIABLE_NAME	VARIABLE_VALUE
+INNODB_STATS_TRADITIONAL	ON
+select * from information_schema.session_variables where variable_name='innodb_stats_traditional';
+VARIABLE_NAME	VARIABLE_VALUE
+INNODB_STATS_TRADITIONAL	ON
+set global innodb_stats_traditional=0;
+select @@global.innodb_stats_traditional;
+@@global.innodb_stats_traditional
+0
+select * from information_schema.global_variables where variable_name='innodb_stats_traditional';
+VARIABLE_NAME	VARIABLE_VALUE
+INNODB_STATS_TRADITIONAL	OFF
+select * from information_schema.session_variables where variable_name='innodb_stats_traditional';
+VARIABLE_NAME	VARIABLE_VALUE
+INNODB_STATS_TRADITIONAL	OFF
+set @@global.innodb_stats_traditional='ON';
+select @@global.innodb_stats_traditional;
+@@global.innodb_stats_traditional
+1
+select * from information_schema.global_variables where variable_name='innodb_stats_traditional';
+VARIABLE_NAME	VARIABLE_VALUE
+INNODB_STATS_TRADITIONAL	ON
+select * from information_schema.session_variables where variable_name='innodb_stats_traditional';
+VARIABLE_NAME	VARIABLE_VALUE
+INNODB_STATS_TRADITIONAL	ON
+set session innodb_stats_traditional='OFF';
+ERROR HY000: Variable 'innodb_stats_traditional' is a GLOBAL variable and should be set with SET GLOBAL
+set @@session.innodb_stats_traditional='ON';
+ERROR HY000: Variable 'innodb_stats_traditional' is a GLOBAL variable and should be set with SET GLOBAL
+set global innodb_stats_traditional=1.1;
+ERROR 42000: Incorrect argument type to variable 'innodb_stats_traditional'
+set global innodb_stats_traditional=1e1;
+ERROR 42000: Incorrect argument type to variable 'innodb_stats_traditional'
+set global innodb_stats_traditional=2;
+ERROR 42000: Variable 'innodb_stats_traditional' can't be set to the value of '2'
+set global innodb_stats_traditional=-3;
+ERROR 42000: Variable 'innodb_stats_traditional' can't be set to the value of '-3'
+select @@global.innodb_stats_traditional;
+@@global.innodb_stats_traditional
+1
+select * from information_schema.global_variables where variable_name='innodb_stats_traditional';
+VARIABLE_NAME	VARIABLE_VALUE
+INNODB_STATS_TRADITIONAL	ON
+select * from information_schema.session_variables where variable_name='innodb_stats_traditional';
+VARIABLE_NAME	VARIABLE_VALUE
+INNODB_STATS_TRADITIONAL	ON
+set global innodb_stats_traditional='AUTO';
+ERROR 42000: Variable 'innodb_stats_traditional' can't be set to the value of 'AUTO'
+SET @@global.innodb_stats_traditional = @start_global_value;
+SELECT @@global.innodb_stats_traditional;
+@@global.innodb_stats_traditional
+0

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

+--source include/have_innodb.inc
+
+SET @start_global_value = @@global.innodb_stats_modified_counter;
+SELECT @start_global_value;
+
+#
+# exists as global only
+#
+--echo Valid values are one or above
+select @@global.innodb_stats_modified_counter >=1;
+select @@global.innodb_stats_modified_counter;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+select @@session.innodb_stats_modified_counter;
+show global variables like 'innodb_stats_modified_counter';
+show session variables like 'innodb_stats_modified_counter';
+select * from information_schema.global_variables where variable_name='innodb_stats_modified_counter';
+select * from information_schema.session_variables where variable_name='innodb_stats_modified_counter';
+
+#
+# show that it's writable
+#
+set global innodb_stats_modified_counter=10;
+select @@global.innodb_stats_modified_counter;
+select * from information_schema.global_variables where variable_name='innodb_stats_modified_counter';
+select * from information_schema.session_variables where variable_name='innodb_stats_modified_counter';
+--error ER_GLOBAL_VARIABLE
+set session innodb_stats_modified_counter=1;
+
+#
+# incorrect types
+#
+--error ER_WRONG_TYPE_FOR_VAR
+set global innodb_stats_modified_counter=1.1;
+--error ER_WRONG_TYPE_FOR_VAR
+set global innodb_stats_modified_counter=1e1;
+--error ER_WRONG_TYPE_FOR_VAR
+set global innodb_stats_modified_counter="foo";
+
+set global innodb_stats_modified_counter=-7;
+select @@global.innodb_stats_modified_counter;
+select * from information_schema.global_variables where variable_name='innodb_stats_modified_counter';
+
+#
+# cleanup
+#
+SET @@global.innodb_stats_modified_counter = @start_global_value;
+SELECT @@global.innodb_stats_modified_counter;

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

+--source include/have_innodb.inc
+
+SET @start_global_value = @@global.innodb_stats_traditional;
+SELECT @start_global_value;
+
+#
+# exists as global only
+#
+--echo Valid values are 'ON' and 'OFF' 
+select @@global.innodb_stats_traditional in (0, 1);
+select @@global.innodb_stats_traditional;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+select @@session.innodb_stats_traditional;
+show global variables like 'innodb_stats_traditional';
+show session variables like 'innodb_stats_traditional';
+select * from information_schema.global_variables where variable_name='innodb_stats_traditional';
+select * from information_schema.session_variables where variable_name='innodb_stats_traditional';
+
+#
+# show that it's writable
+#
+set global innodb_stats_traditional='OFF';
+select @@global.innodb_stats_traditional;
+select * from information_schema.global_variables where variable_name='innodb_stats_traditional';
+select * from information_schema.session_variables where variable_name='innodb_stats_traditional';
+set @@global.innodb_stats_traditional=1;
+select @@global.innodb_stats_traditional;
+select * from information_schema.global_variables where variable_name='innodb_stats_traditional';
+select * from information_schema.session_variables where variable_name='innodb_stats_traditional';
+set global innodb_stats_traditional=0;
+select @@global.innodb_stats_traditional;
+select * from information_schema.global_variables where variable_name='innodb_stats_traditional';
+select * from information_schema.session_variables where variable_name='innodb_stats_traditional';
+set @@global.innodb_stats_traditional='ON';
+select @@global.innodb_stats_traditional;
+select * from information_schema.global_variables where variable_name='innodb_stats_traditional';
+select * from information_schema.session_variables where variable_name='innodb_stats_traditional';
+--error ER_GLOBAL_VARIABLE
+set session innodb_stats_traditional='OFF';
+--error ER_GLOBAL_VARIABLE
+set @@session.innodb_stats_traditional='ON';
+
+#
+# incorrect types
+#
+--error ER_WRONG_TYPE_FOR_VAR
+set global innodb_stats_traditional=1.1;
+--error ER_WRONG_TYPE_FOR_VAR
+set global innodb_stats_traditional=1e1;
+--error ER_WRONG_VALUE_FOR_VAR
+set global innodb_stats_traditional=2;
+--error ER_WRONG_VALUE_FOR_VAR
+set global innodb_stats_traditional=-3;
+select @@global.innodb_stats_traditional;
+select * from information_schema.global_variables where variable_name='innodb_stats_traditional';
+select * from information_schema.session_variables where variable_name='innodb_stats_traditional';
+--error ER_WRONG_VALUE_FOR_VAR
+set global innodb_stats_traditional='AUTO';
+
+#
+# Cleanup
+#
+
+SET @@global.innodb_stats_traditional = @start_global_value;
+SELECT @@global.innodb_stats_traditional;

storage/innobase/btr/btr0cur.c

@@ -3764,16 +3764,29 @@ btr_estimate_number_of_different_key_vals(
 		ut_error;
         }
 
-	/* It makes no sense to test more pages than are contained
-	in the index, thus we lower the number if it is too high */
-	if (srv_stats_sample_pages > index->stat_index_size) {
+	if (srv_stats_sample_traditional) {
+		/* It makes no sense to test more pages than are contained
+		in the index, thus we lower the number if it is too high */
+		if (srv_stats_sample_pages > index->stat_index_size) {
+			if (index->stat_index_size > 0) {
+				n_sample_pages = index->stat_index_size;
+			} else {
+				n_sample_pages = 1;
+			}
+		} else {
+			n_sample_pages = srv_stats_sample_pages;
+		}
+	} else {
+		/* New logaritmic number of pages that are estimated. We
+		first pick minimun from srv_stats_sample_pages and number of
+		pages on index. Then we pick maximum from previous number of
+		pages and log2(number of index pages) * srv_stats_sample_pages. */
 		if (index->stat_index_size > 0) {
-			n_sample_pages = index->stat_index_size;
+			n_sample_pages = ut_max(ut_min(srv_stats_sample_pages, index->stat_index_size),
+				                log2(index->stat_index_size)*srv_stats_sample_pages);
 		} else {
 			n_sample_pages = 1;
 		}
-	} else {
-		n_sample_pages = srv_stats_sample_pages;
 	}
 
 	/* We sample some pages in the index to get an estimate */

storage/innobase/handler/ha_innodb.cc

@@ -11739,6 +11739,16 @@ static MYSQL_SYSVAR_ULONGLONG(stats_sample_pages, srv_stats_sample_pages,
   "The number of index pages to sample when calculating statistics (default 8)",
   NULL, NULL, 8, 1, ~0ULL, 0);
 
+static MYSQL_SYSVAR_ULONGLONG(stats_modified_counter, srv_stats_modified_counter,
+  PLUGIN_VAR_RQCMDARG,
+  "The number of rows modified before we calculate new statistics (default 0 = current limits)",
+  NULL, NULL, 0, 0, ~0ULL, 0);
+
+static MYSQL_SYSVAR_BOOL(stats_traditional, srv_stats_sample_traditional,
+  PLUGIN_VAR_RQCMDARG,
+  "Enable traditional statistic calculation based on number of configured pages (default false)",
+  NULL, NULL, FALSE);
+
 static MYSQL_SYSVAR_BOOL(adaptive_hash_index, btr_search_enabled,
   PLUGIN_VAR_OPCMDARG,
   "Enable InnoDB adaptive hash index (enabled by default).  "
@@ -12001,6 +12011,8 @@ static struct st_mysql_sys_var* innobase_system_variables[]= {
   MYSQL_SYSVAR(rollback_on_timeout),
   MYSQL_SYSVAR(stats_on_metadata),
   MYSQL_SYSVAR(stats_sample_pages),
+  MYSQL_SYSVAR(stats_modified_counter),
+  MYSQL_SYSVAR(stats_traditional),
   MYSQL_SYSVAR(adaptive_hash_index),
   MYSQL_SYSVAR(stats_method),
   MYSQL_SYSVAR(replication_delay),

storage/innobase/include/dict0dict.h

@@ -1123,7 +1123,13 @@ dict_index_calc_min_rec_len(
 /*========================*/
 	const dict_index_t*	index);	/*!< in: index */
 
-/** Calculate new statistics if 1 / 16 of table has been modified
+/**
+
+If user has provided upper bound for how many rows needs to be updated
+before we calculate new statistics we use minimum of provided value
+and 1/16 of table every 16th round. If no upper bound is provided
+(srv_stats_modified_counter = 0, default) then calculate new statistics
+if 1 / 16 of table has been modified
 since the last time a statistics batch was run.
 We calculate statistics at most every 16th round, since we may have
 a counter table which is very small and updated very often.
@@ -1132,7 +1138,9 @@ a counter table which is very small and updated very often.
 recalculated
 */
 #define DICT_TABLE_CHANGED_TOO_MUCH(t) \
-	((ib_int64_t) (t)->stat_modified_counter > 16 + (t)->stat_n_rows / 16)
+	((ib_int64_t) (t)->stat_modified_counter > (srv_stats_modified_counter ? \
+	ut_min(srv_stats_modified_counter, (16 + (t)->stat_n_rows / 16)) : \
+		16 + (t)->stat_n_rows / 16))
 
 /*********************************************************************//**
 Calculates new estimates for table and index statistics. The statistics

storage/innobase/include/srv0srv.h

@@ -211,6 +211,8 @@ extern ulint	srv_fast_shutdown;	 /* If this is 1, do not do a
 extern ibool	srv_innodb_status;
 
 extern unsigned long long	srv_stats_sample_pages;
+extern unsigned long long	srv_stats_modified_counter;
+extern my_bool			srv_stats_sample_traditional;
 
 extern ibool	srv_use_doublewrite_buf;
 extern ibool	srv_use_atomic_writes;

storage/innobase/srv/srv0srv.c

@@ -749,6 +749,13 @@ static ulint	srv_meter_high_water[SRV_MASTER + 1];
 static ulint	srv_meter_high_water2[SRV_MASTER + 1];
 static ulint	srv_meter_foreground[SRV_MASTER + 1];
 #endif
+/* The number of rows modified before we calculate new statistics (default 0
+= current limits) */
+UNIV_INTERN unsigned long long srv_stats_modified_counter = 0;
+
+/* Enable traditional statistic calculation based on number of configured
+pages default false. */
+UNIV_INTERN my_bool	srv_stats_sample_traditional = FALSE;
 
 /* The following values give info about the activity going on in
 the database. They are protected by the server mutex. The arrays

storage/xtradb/btr/btr0cur.c

@@ -3944,16 +3944,29 @@ btr_estimate_number_of_different_key_vals(
 		ut_error;
         }
 
-	/* It makes no sense to test more pages than are contained
-	in the index, thus we lower the number if it is too high */
-	if (srv_stats_sample_pages > index->stat_index_size) {
+	if (srv_stats_sample_traditional) {
+		/* It makes no sense to test more pages than are contained
+		in the index, thus we lower the number if it is too high */
+		if (srv_stats_sample_pages > index->stat_index_size) {
+			if (index->stat_index_size > 0) {
+				n_sample_pages = index->stat_index_size;
+			} else {
+				n_sample_pages = 1;
+			}
+		} else {
+			n_sample_pages = srv_stats_sample_pages;
+		}
+	} else {
+		/* New logaritmic number of pages that are estimated. We
+		first pick minimun from srv_stats_sample_pages and number of
+		pages on index. Then we pick maximum from previous number of
+		pages and log2(number of index pages) * srv_stats_sample_pages. */
 		if (index->stat_index_size > 0) {
-			n_sample_pages = index->stat_index_size;
+			n_sample_pages = ut_max(ut_min(srv_stats_sample_pages, index->stat_index_size),
+				                log2(index->stat_index_size)*srv_stats_sample_pages);
 		} else {
 			n_sample_pages = 1;
 		}
-	} else {
-		n_sample_pages = srv_stats_sample_pages;
 	}
 
 	/* We sample some pages in the index to get an estimate */

storage/xtradb/handler/ha_innodb.cc

@@ -13107,6 +13107,16 @@ static MYSQL_SYSVAR_ULONGLONG(stats_sample_pages, srv_stats_sample_pages,
   "The number of index pages to sample when calculating statistics (default 8)",
   NULL, NULL, 8, 1, ~0ULL, 0);
 
+static MYSQL_SYSVAR_ULONGLONG(stats_modified_counter, srv_stats_modified_counter,
+  PLUGIN_VAR_RQCMDARG,
+  "The number of rows modified before we calculate new statistics (default 0 = current limits)",
+  NULL, NULL, 0, 0, ~0ULL, 0);
+
+static MYSQL_SYSVAR_BOOL(stats_traditional, srv_stats_sample_traditional,
+  PLUGIN_VAR_RQCMDARG,
+  "Enable traditional statistic calculation based on number of configured pages (default false)",
+  NULL, NULL, FALSE);
+
 static MYSQL_SYSVAR_ULINT(stats_auto_update, srv_stats_auto_update,
   PLUGIN_VAR_RQCMDARG,
   "Enable/Disable InnoDB's auto update statistics of indexes. "
@@ -13680,6 +13690,8 @@ static struct st_mysql_sys_var* innobase_system_variables[]= {
   MYSQL_SYSVAR(persistent_stats_root_page),
 #endif
   MYSQL_SYSVAR(stats_sample_pages),
+  MYSQL_SYSVAR(stats_modified_counter),
+  MYSQL_SYSVAR(stats_traditional),
   MYSQL_SYSVAR(adaptive_hash_index),
   MYSQL_SYSVAR(adaptive_hash_index_partitions),
   MYSQL_SYSVAR(stats_method),

storage/xtradb/include/dict0dict.h

@@ -1123,7 +1123,13 @@ dict_index_calc_min_rec_len(
 /*========================*/
 	const dict_index_t*	index);	/*!< in: index */
 
-/** Calculate new statistics if 1 / 16 of table has been modified
+/**
+
+If user has provided upper bound for how many rows needs to be updated
+before we calculate new statistics we use minimum of provided value
+and 1/16 of table every 16th round. If no upper bound is provided
+(srv_stats_modified_counter = 0, default) then calculate new statistics
+if 1 / 16 of table has been modified
 since the last time a statistics batch was run.
 We calculate statistics at most every 16th round, since we may have
 a counter table which is very small and updated very often.
@@ -1132,7 +1138,9 @@ a counter table which is very small and updated very often.
 recalculated
 */
 #define DICT_TABLE_CHANGED_TOO_MUCH(t) \
-	((ib_int64_t) (t)->stat_modified_counter > 16 + (t)->stat_n_rows / 16)
+	((ib_int64_t) (t)->stat_modified_counter > (srv_stats_modified_counter ? \
+	ut_min(srv_stats_modified_counter, (16 + (t)->stat_n_rows / 16)) : \
+		16 + (t)->stat_n_rows / 16))
 
 /*********************************************************************//**
 Calculates new estimates for table and index statistics. The statistics

storage/xtradb/include/srv0srv.h

@@ -242,6 +242,8 @@ extern ulint	srv_fast_shutdown;	 /* If this is 1, do not do a
 extern ibool	srv_innodb_status;
 
 extern unsigned long long	srv_stats_sample_pages;
+extern unsigned long long	srv_stats_modified_counter;
+extern my_bool			srv_stats_sample_traditional;
 extern ulint	srv_stats_auto_update;
 extern ulint	srv_stats_update_need_lock;
 extern ibool	srv_use_sys_stats_table;

storage/xtradb/srv/srv0srv.c

@@ -411,6 +411,13 @@ UNIV_INTERN ibool	srv_use_sys_stats_table = FALSE;
 #ifdef UNIV_DEBUG
 UNIV_INTERN ulong	srv_sys_stats_root_page = 0;
 #endif
+/* The number of rows modified before we calculate new statistics (default 0
+= current limits) */
+UNIV_INTERN unsigned long long srv_stats_modified_counter = 0;
+
+/* Enable traditional statistic calculation based on number of configured
+pages default false. */
+UNIV_INTERN my_bool	srv_stats_sample_traditional = FALSE;
 
 UNIV_INTERN ibool	srv_use_doublewrite_buf	= TRUE;
 UNIV_INTERN ibool       srv_use_atomic_writes = FALSE;