Fixed bug mdev-11096.

1. When min/max value is provided the null flag for it must be set to 0 in the bitmap Culumn_statistics::column_stat_nulls. 2. When the calculation of the selectivity of the range condition over a column requires min and max values for the column then we have to check that these values are provided.
MariaDB · Oct 27, 2016 · 9d4a0dd · 9d4a0dd
1 parent 26b87c3
commit 9d4a0dd
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Showing 5 changed files with 78 additions and 13 deletions.
diff --git a/mysql-test/r/selectivity.result b/mysql-test/r/selectivity.result
@@ -1446,3 +1446,27 @@ a	b	i
 set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
 DROP TABLE t1,t2;
 set use_stat_tables=@save_use_stat_tables;
+#
+# Bug mdev-11096: range condition over column without statistical data
+#
+set use_stat_tables='preferably';
+set optimizer_use_condition_selectivity=3;
+create table t1(col1 char(32));
+insert into t1 values ('a'),('b'),('c'),('d'), ('e'),('f'),('g'),('h');
+analyze table t1 persistent for columns () indexes ();
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+explain extended 
+select * from t1 where col1 > 'b' and col1 < 'e';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	8	100.00	Using where
+Warnings:
+Note	1003	select `test`.`t1`.`col1` AS `col1` from `test`.`t1` where ((`test`.`t1`.`col1` > 'b') and (`test`.`t1`.`col1` < 'e'))
+select * from t1 where col1 > 'b' and col1 < 'e';
+col1
+c
+d
+drop table t1;
+set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
+set use_stat_tables=@save_use_stat_tables;
diff --git a/mysql-test/r/selectivity_innodb.result b/mysql-test/r/selectivity_innodb.result
@@ -802,9 +802,9 @@ insert into t2 values (2),(3);
 explain extended 
 select * from t1 where a in ( select b from t2 ) AND ( a > 3 );
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	1	0.00	Using where
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	1	100.00	Using where
 1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	4	func	1	100.00	
-2	MATERIALIZED	t2	ALL	NULL	NULL	NULL	NULL	2	0.00	
+2	MATERIALIZED	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	
 Warnings:
 Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t1`.`a` > 3))
 select * from t1 where a in ( select b from t2 ) AND ( a > 3 );
@@ -1450,6 +1450,30 @@ a	b	i
 set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
 DROP TABLE t1,t2;
 set use_stat_tables=@save_use_stat_tables;
+#
+# Bug mdev-11096: range condition over column without statistical data
+#
+set use_stat_tables='preferably';
+set optimizer_use_condition_selectivity=3;
+create table t1(col1 char(32));
+insert into t1 values ('a'),('b'),('c'),('d'), ('e'),('f'),('g'),('h');
+analyze table t1 persistent for columns () indexes ();
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+explain extended 
+select * from t1 where col1 > 'b' and col1 < 'e';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	8	100.00	Using where
+Warnings:
+Note	1003	select `test`.`t1`.`col1` AS `col1` from `test`.`t1` where ((`test`.`t1`.`col1` > 'b') and (`test`.`t1`.`col1` < 'e'))
+select * from t1 where col1 > 'b' and col1 < 'e';
+col1
+c
+d
+drop table t1;
+set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
+set use_stat_tables=@save_use_stat_tables;
 set optimizer_switch=@save_optimizer_switch_for_selectivity_test;
 set @tmp_ust= @@use_stat_tables;
 set @tmp_oucs= @@optimizer_use_condition_selectivity;

diff --git a/mysql-test/t/selectivity.test b/mysql-test/t/selectivity.test
@@ -970,6 +970,25 @@ set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivit
 
 DROP TABLE t1,t2;
 
+set use_stat_tables=@save_use_stat_tables;
+
+--echo #
+--echo # Bug mdev-11096: range condition over column without statistical data
+--echo #
+
+set use_stat_tables='preferably';
+set optimizer_use_condition_selectivity=3;
 
+create table t1(col1 char(32));
+insert into t1 values ('a'),('b'),('c'),('d'), ('e'),('f'),('g'),('h');
+analyze table t1 persistent for columns () indexes ();
+
+explain extended 
+select * from t1 where col1 > 'b' and col1 < 'e';
+select * from t1 where col1 > 'b' and col1 < 'e';
+
+drop table t1;
+
+set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
 set use_stat_tables=@save_use_stat_tables;
 
diff --git a/sql/sql_statistics.cc b/sql/sql_statistics.cc
@@ -1003,11 +1003,13 @@ class Column_stat: public Stat_table
 
           switch (i) {
           case COLUMN_STAT_MIN_VALUE:
+	    table_field->read_stats->min_value->set_notnull();
             stat_field->val_str(&val);
             table_field->read_stats->min_value->store(val.ptr(), val.length(),
                                                       &my_charset_bin);
             break;
           case COLUMN_STAT_MAX_VALUE:
+	    table_field->read_stats->max_value->set_notnull();
             stat_field->val_str(&val);
             table_field->read_stats->max_value->store(val.ptr(), val.length(),
                                                       &my_charset_bin);
@@ -3659,17 +3661,8 @@ double get_column_range_cardinality(Field *field,
     {
       double avg_frequency= col_stats->get_avg_frequency();
       res= avg_frequency;   
-      /*
-        psergey-todo: what does check for min_value, max_value mean? 
-          min/max_value are set to NULL in alloc_statistics_for_table() and
-          alloc_statistics_for_table_share().  Both functions will immediately
-          call create_min_max_statistical_fields_for_table and 
-          create_min_max_statistical_fields_for_table_share() respectively,
-          which will set min/max_value to be valid pointers, unless OOM
-          occurs.
-      */
       if (avg_frequency > 1.0 + 0.000001 && 
-          col_stats->min_value && col_stats->max_value)
+          col_stats->min_max_values_are_provided())
       {
         Histogram *hist= &col_stats->histogram;
         if (hist->is_available())
@@ -3692,7 +3685,7 @@ double get_column_range_cardinality(Field *field,
   }  
   else 
   {
-    if (col_stats->min_value && col_stats->max_value)
+    if (col_stats->min_max_values_are_provided())
     {
       double sel, min_mp_pos, max_mp_pos;
 

diff --git a/sql/sql_statistics.h b/sql/sql_statistics.h
@@ -388,6 +388,11 @@ class Column_statistics
     avg_frequency= (ulong) (val * Scale_factor_avg_frequency);
   }
 
+  bool min_max_values_are_provided()
+  {
+    return !is_null(COLUMN_STAT_MIN_VALUE) && 
+      !is_null(COLUMN_STAT_MIN_VALUE);
+  }          
 };