MDEV-4345: fixed optimizer_selectivity_sampling_limit default value.

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

 SET @start_global_value = @@global.optimizer_selectivity_sampling_limit;
 SELECT @start_global_value;
 @start_global_value
-5000
+100
 SET @start_session_value = @@session.optimizer_selectivity_sampling_limit;
 SELECT @start_session_value;
 @start_session_value
-5000
+100
 '#--------------------FN_DYNVARS_115_01-------------------------#'
 SET @@global.optimizer_selectivity_sampling_limit = DEFAULT;
 SELECT @@global.optimizer_selectivity_sampling_limit;
 @@global.optimizer_selectivity_sampling_limit
-5000
+100
 SET @@session.optimizer_selectivity_sampling_limit = DEFAULT;
 SELECT @@session.optimizer_selectivity_sampling_limit;
 @@session.optimizer_selectivity_sampling_limit
-5000
+100
 '#--------------------FN_DYNVARS_115_02-------------------------#'
 SET @@global.optimizer_selectivity_sampling_limit = DEFAULT;
-SELECT @@global.optimizer_selectivity_sampling_limit = 5000;
-@@global.optimizer_selectivity_sampling_limit = 5000
+SELECT @@global.optimizer_selectivity_sampling_limit = 100;
+@@global.optimizer_selectivity_sampling_limit = 100
 1
 SET @@session.optimizer_selectivity_sampling_limit = DEFAULT;
-SELECT @@session.optimizer_selectivity_sampling_limit = 5000;
-@@session.optimizer_selectivity_sampling_limit = 5000
+SELECT @@session.optimizer_selectivity_sampling_limit = 100;
+@@session.optimizer_selectivity_sampling_limit = 100
 1
 '#--------------------FN_DYNVARS_115_03-------------------------#'
 SELECT @@global.optimizer_selectivity_sampling_limit;
 @@global.optimizer_selectivity_sampling_limit
-5000
+100
 SET @@global.optimizer_selectivity_sampling_limit = 9;
 Warnings:
 Warning	1292	Truncated incorrect optimizer_selectivity_sampling_l value: '9'
@@ -63,7 +63,7 @@ SELECT @@global.optimizer_selectivity_sampling_limit;
 '#--------------------FN_DYNVARS_115_04-------------------------#'
 SELECT @@session.optimizer_selectivity_sampling_limit;
 @@session.optimizer_selectivity_sampling_limit
-5000
+100
 SET @@session.optimizer_selectivity_sampling_limit = 9;
 Warnings:
 Warning	1292	Truncated incorrect optimizer_selectivity_sampling_l value: '9'
@@ -134,8 +134,8 @@ SELECT @@local.optimizer_selectivity_sampling_limit = @@session.optimizer_select
 SET @@global.optimizer_selectivity_sampling_limit = @start_global_value;
 SELECT @@global.optimizer_selectivity_sampling_limit;
 @@global.optimizer_selectivity_sampling_limit
-5000
+100
 SET @@session.optimizer_selectivity_sampling_limit = @start_session_value;
 SELECT @@session.optimizer_selectivity_sampling_limit;
 @@session.optimizer_selectivity_sampling_limit
-5000
+100

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

@@ -34,10 +34,10 @@ SELECT @@session.optimizer_selectivity_sampling_limit;
 #########################################################################
 
 SET @@global.optimizer_selectivity_sampling_limit = DEFAULT;
-SELECT @@global.optimizer_selectivity_sampling_limit = 5000;
+SELECT @@global.optimizer_selectivity_sampling_limit = 100;
 
 SET @@session.optimizer_selectivity_sampling_limit = DEFAULT;
-SELECT @@session.optimizer_selectivity_sampling_limit = 5000;
+SELECT @@session.optimizer_selectivity_sampling_limit = 100;
 
 
 --echo '#--------------------FN_DYNVARS_115_03-------------------------#'

sql/opt_range.h

@@ -1052,7 +1052,7 @@ void store_key_image_to_rec(Field *field, uchar *ptr, uint len);
 extern String null_string;
 
 /* check this number of rows (default value) */
-#define SELECTIVITY_SAMPLING_LIMIT 5000
+#define SELECTIVITY_SAMPLING_LIMIT 100
 /* but no more then this part of table (10%) */
 #define SELECTIVITY_SAMPLING_SHARE 0.10
 /* do not check if we are going check less then this number of records */