Bug #12796: Record lost in HEAP table

Two handler objects were present, one was used for an insert and the other for a select
The state of the statistics was local to the handler object and thus the other handler
object didn't notice the insert.
Fix included:
1) Add a new variable key_stat_version added to whenever statistics was considered in need
of update (previously key_stats_ok= FALSE in those places)
2) Add a new handler variable key_stat_version assigned whenever key_stats_ok= TRUE was set
previously
3) Fix records_in_range to return records if records <= 1
4) Fix records_in_range to add 2 to rec_per_key to ensure we don't specify 0 or 1 when it isn't
and thus invoking incorrect optimisations.
5) Fix unique key handling for HEAP table in records_in_range

1 files changed, 11 insertions, 1 deletions

diff --git a/mysql-test/r/heap.result b/mysql-test/r/heap.result
index 53dec294ef8..e3b9f7db984 100644
--- a/mysql-test/r/heap.result
+++ b/mysql-test/r/heap.result
@@ -182,7 +182,7 @@ SELECT * FROM t1 WHERE a=NULL;
 a	b
 explain SELECT * FROM t1 WHERE a IS NULL;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ref	a	a	5	const	1	Using where
+1	SIMPLE	t1	ref	a	a	5	const	2	Using where
 SELECT * FROM t1 WHERE a<=>NULL;
 a	b
 NULL	99
@@ -296,3 +296,13 @@ insert into t1 values ("abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcd
 insert into t1 values ("abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz");
 ERROR 23000: Duplicate entry 'abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijkl' for key 1
 drop table t1;
+CREATE TABLE t1 (a int, key(a)) engine=heap;
+insert delayed into t1 values (0);
+delete from t1;
+select * from t1;
+a
+insert delayed into t1 values (0), (1);
+select * from t1 where a = 0;
+a
+0
+drop table t1;