Fixed bug mdev-4363.

When calculating the selectivity of a range in the function
get_column_range_cardinality a check whether NULL values are
included into into the range must be done.

1 files changed, 33 insertions, 1 deletions

diff --git a/mysql-test/t/selectivity.test b/mysql-test/t/selectivity.test
index f601d4f656a..d8ab19ac28a 100644
--- a/mysql-test/t/selectivity.test
+++ b/mysql-test/t/selectivity.test
@@ -483,7 +483,7 @@ INSERT INTO t2 VALUES (4),(5),(2),(5),(1),(1),(2);
 ANALYZE TABLE t1, t2;
 FLUSH TABLES;
 
-SET optimizer_use_condition_selectivity=3;
+set optimizer_use_condition_selectivity=3;
 
 EXPLAIN EXTENDED
 SELECT * FROM t1, t2 WHERE EXISTS ( SELECT 1 FROM t1, t2 ) AND a != b OR a <= 4;
@@ -495,4 +495,36 @@ DROP TABLE t1,t2;
 set use_stat_tables=@save_use_stat_tables;
 
 
+--echo #
+--echo # Bug mdev-4363: selectivity of the condition a IS NULL OR IS NOT NULL   
+--echo #                with optimizer_use_condition_selectivity=3
+--echo #
+
+set use_stat_tables = PREFERABLY;
+
+CREATE TABLE t1 (a int);
+INSERT INTO t1 VALUES 
+  (1),(7),(4),(7),(NULL),(2),(NULL),(4),(NULL),(NULL),(1),(3),(8),(8);
+
+ANALYZE TABLE t1;
+FLUSH TABLE t1;
+
+set optimizer_use_condition_selectivity=3;
+
+EXPLAIN EXTENDED
+SELECT * FROM t1 WHERE a IS NULL;
+EXPLAIN EXTENDED
+SELECT * FROM t1 WHERE a IS NOT NULL;
+EXPLAIN EXTENDED
+SELECT * FROM t1 WHERE a IS NULL OR a IS NOT NULL;
+EXPLAIN EXTENDED
+SELECT * FROM t1 WHERE a IS NULL OR a < 5;
+
+set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
+
+DROP TABLE t1;
+
+set use_stat_tables=@save_use_stat_tables;
+
+
 set use_stat_tables=@save_use_stat_tables;