Bug#10178 - failure to find a row in heap table by concurrent UPDATEs

Moved the key statistics update to info().
The table is not locked in open(). This made wrong stats possible.

No test case for the test suite.
This happens only with heavy concurrency.
A test script is added to the bug report.


mysql-test/r/heap_hash.result:
  Bug#10178 - failure to find a row in heap table by concurrent UPDATEs
  Updated test results to reflect the new  statistics behaviour.
mysql-test/t/heap_hash.test:
  Bug#10178 - failure to find a row in heap table by concurrent UPDATEs
  Added a FLUSH TABLES to avoid statistics differences between normal 
  and ps-protocol tests.
sql/ha_heap.cc:
  Bug#10178 - failure to find a row in heap table by concurrent UPDATEs
  Moved the key statistics update to info().
  The table is not locked in open(). This made wrong stats possible.
sql/ha_heap.h:
  Bug#10178 - failure to find a row in heap table by concurrent UPDATEs
  Added an element to track the validity of the key statistics.

1 files changed, 12 insertions, 11 deletions

diff --git a/mysql-test/r/heap_hash.result b/mysql-test/r/heap_hash.result
index d3673cd2a63..e5098ab8c87 100644
--- a/mysql-test/r/heap_hash.result
+++ b/mysql-test/r/heap_hash.result
@@ -231,18 +231,19 @@ explain select * from t1 where a='aaad';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ref	a	a	8	const	1	Using where
 insert into t1 select * from t1;
+flush tables;
 explain select * from t1 where a='aaaa';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ref	a	a	8	const	1	Using where
+1	SIMPLE	t1	ref	a	a	8	const	2	Using where
 explain select * from t1 where a='aaab';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ref	a	a	8	const	1	Using where
+1	SIMPLE	t1	ref	a	a	8	const	2	Using where
 explain select * from t1 where a='aaac';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ref	a	a	8	const	1	Using where
+1	SIMPLE	t1	ref	a	a	8	const	2	Using where
 explain select * from t1 where a='aaad';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ref	a	a	8	const	1	Using where
+1	SIMPLE	t1	ref	a	a	8	const	2	Using where
 flush tables;
 explain select * from t1 where a='aaaa';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
@@ -261,16 +262,16 @@ delete from t1;
 insert into t1 select * from t2;
 explain select * from t1 where a='aaaa';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ref	a	a	8	const	1	Using where
+1	SIMPLE	t1	ref	a	a	8	const	2	Using where
 explain select * from t1 where a='aaab';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ref	a	a	8	const	1	Using where
+1	SIMPLE	t1	ref	a	a	8	const	2	Using where
 explain select * from t1 where a='aaac';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ref	a	a	8	const	1	Using where
+1	SIMPLE	t1	ref	a	a	8	const	2	Using where
 explain select * from t1 where a='aaad';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ref	a	a	8	const	1	Using where
+1	SIMPLE	t1	ref	a	a	8	const	2	Using where
 drop table t1, t2;
 create table t1 (
 id int unsigned not null primary key auto_increment, 
@@ -345,15 +346,15 @@ insert into t3 select name, name from t1;
 show index from t3;
 Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment
 t3	1	a	1	a	NULL	NULL	NULL	NULL		HASH	
-t3	1	a	2	b	NULL	15	NULL	NULL		HASH	
+t3	1	a	2	b	NULL	13	NULL	NULL		HASH	
 show index from t3;
 Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment
 t3	1	a	1	a	NULL	NULL	NULL	NULL		HASH	
-t3	1	a	2	b	NULL	15	NULL	NULL		HASH	
+t3	1	a	2	b	NULL	13	NULL	NULL		HASH	
 explain select * from t1 ignore key(btree_idx), t3 where t1.name='matt' and t3.a = concat('',t1.name) and t3.b=t1.name;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ref	heap_idx	heap_idx	20	const	7	Using where
-1	SIMPLE	t3	ref	a	a	40	func,const	6	Using where
+1	SIMPLE	t3	ref	a	a	40	func,const	7	Using where
 drop table t1, t2, t3;
 create temporary table t1 ( a int, index (a) ) engine=memory;
 insert into t1 values (1),(2),(3),(4),(5);