Fixed bug mdev-4370.

Don't try to a histogram if it is not read into the cache for statistical data.
It may happen so if optimizer_use_condition_selectivity is set to 3. This 
setting orders the optimizer not use histograms to calculate selectivity.

1 files changed, 28 insertions, 0 deletions

diff --git a/mysql-test/r/selectivity_innodb.result b/mysql-test/r/selectivity_innodb.result
index cc9b5475ac1..256b93d8cb5 100644
--- a/mysql-test/r/selectivity_innodb.result
+++ b/mysql-test/r/selectivity_innodb.result
@@ -801,6 +801,34 @@ SELECT 1 FROM t1, t2 WHERE pk = 6 AND a = 2 AND b = 10;
 1
 DROP TABLE t1,t2;
 set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
+#
+# Bug mdev-4370: Histograms have bean created, but the query is run after
+#                FLUSH TABLES with optimizer_use_condition_selectivity=3
+#
+set use_stat_tables=PREFERABLY;
+set histogram_size=10;
+set histogram_type='SINGLE_PREC_HB';
+CREATE TABLE t1 (a int);
+INSERT INTO t1 VALUES (9), (1);
+ANALYZE TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	OK
+FLUSH TABLES;
+set optimizer_use_condition_selectivity=3;
+EXPLAIN EXTENDED
+SELECT * FROM t1 WHERE a > 3;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	75.00	Using where
+Warnings:
+Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` where (`test`.`t1`.`a` > 3)
+SELECT * FROM t1 WHERE a > 3;
+a
+9
+set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
+DROP TABLE t1;
+set histogram_size=@save_histogram_size;
+set histogram_type=@save_histogram_type;
+set use_stat_tables=@save_use_stat_tables;
 set use_stat_tables=@save_use_stat_tables;
 set optimizer_switch=@save_optimizer_switch_for_selectivity_test;
 SET SESSION STORAGE_ENGINE=DEFAULT;