Bug#35745: SELECT COUNT(*) is not correct for some partitioned tables.

problem was that ha_partition::records was not implemented, thus
using the default handler::records, which is not correct if the engine
does not support HA_STATS_RECORDS_IS_EXACT.
Solution was to implement ha_partition::records as a wrapper around
the underlying partitions records.

The rows column in explain partitions will now include the total
number of records in the partitioned table.

(recommit after removing out-commented code)

1 files changed, 33 insertions, 33 deletions

diff --git a/mysql-test/r/partition_pruning.result b/mysql-test/r/partition_pruning.result
index 396400f9010..b153ad9ad47 100644
--- a/mysql-test/r/partition_pruning.result
+++ b/mysql-test/r/partition_pruning.result
@@ -31,7 +31,7 @@ id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	p0,p1	ALL	NULL	NULL	NULL	NULL	3	Using where
 explain partitions select * from t2 where a=1 and b=1;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t2	p0	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	SIMPLE	t2	p0	ALL	NULL	NULL	NULL	NULL	3	Using where
 create table t3 (
 a int
 )
@@ -89,25 +89,25 @@ id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
 explain partitions select * from t5
 where (a=10 and b=1) or (a=10 and b=2) or (a=10 and b = 3);
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t5	p0_p0sp0,p0_p0sp1	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	SIMPLE	t5	p0_p0sp0,p0_p0sp1	ALL	NULL	NULL	NULL	NULL	4	Using where
 explain partitions select * from t5 where (a=10 and b=2) or (a=10 and b=3)
 or (a=10 and b = 4);
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t5	p0_p0sp0,p0_p0sp1,p1_p1sp0,p1_p1sp1	ALL	NULL	NULL	NULL	NULL	4	Using where
 explain partitions select * from t5 where (c=1 and d=1);
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t5	p0_p0sp0,p1_p1sp0	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	SIMPLE	t5	p0_p0sp0,p1_p1sp0	ALL	NULL	NULL	NULL	NULL	4	Using where
 explain partitions select * from t5 where (c=2 and d=1);
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t5	p0_p0sp1,p1_p1sp1	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	SIMPLE	t5	p0_p0sp1,p1_p1sp1	ALL	NULL	NULL	NULL	NULL	4	Using where
 explain partitions select * from t5 where (a=10 and b=2 and c=1 and d=1) or 
 (c=2 and d=1);
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t5	p0_p0sp0,p0_p0sp1,p1_p1sp1	ALL	NULL	NULL	NULL	NULL	3	Using where
+1	SIMPLE	t5	p0_p0sp0,p0_p0sp1,p1_p1sp1	ALL	NULL	NULL	NULL	NULL	4	Using where
 explain partitions select * from t5 where (a=10 and b=2 and c=1 and d=1) or 
 (b=2 and c=2 and d=1);
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t5	p0_p0sp0,p0_p0sp1,p1_p1sp1	ALL	NULL	NULL	NULL	NULL	3	Using where
+1	SIMPLE	t5	p0_p0sp0,p0_p0sp1,p1_p1sp1	ALL	NULL	NULL	NULL	NULL	4	Using where
 create table t6 (a int not null) partition by LIST(a) (
 partition p1 values in (1),
 partition p3 values in (3),
@@ -145,7 +145,7 @@ id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t6	p5,p7,p9	system	NULL	NULL	NULL	NULL	1	
 explain partitions select * from t6 where a >= 3 and a <= 8;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t6	p3,p5,p7	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	SIMPLE	t6	p3,p5,p7	ALL	NULL	NULL	NULL	NULL	3	Using where
 explain partitions select * from t6 where a > 3 and a < 5;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
@@ -187,7 +187,7 @@ id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t6	p5,p7,p9	system	NULL	NULL	NULL	NULL	1	
 explain partitions select * from t6 where a >= 3 and a <= 8;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t6	p3,p5,p7	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	SIMPLE	t6	p3,p5,p7	ALL	NULL	NULL	NULL	NULL	3	Using where
 explain partitions select * from t6 where a > 3 and a < 5;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
@@ -342,7 +342,7 @@ id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
 explain partitions
 select * from t1 X, t1 Y where X.a = Y.a and (X.a=1 or X.a=2);
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	X	p1,p2	ALL	a	NULL	NULL	NULL	2	Using where
+1	SIMPLE	X	p1,p2	ALL	a	NULL	NULL	NULL	4	Using where
 1	SIMPLE	Y	p1,p2	ref	a	a	4	test.X.a	2	
 drop table t1;
 create table t1 (a int) partition by hash(a) partitions 20;
@@ -355,7 +355,7 @@ id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	p1,p2	ALL	NULL	NULL	NULL	NULL	2	Using where
 explain partitions select * from t1 where a >  1 and a <= 3;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	p2,p3	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	SIMPLE	t1	p2,p3	ALL	NULL	NULL	NULL	NULL	3	Using where
 explain partitions select * from t1 where a >= 1 and a <= 3;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	p1,p2,p3	ALL	NULL	NULL	NULL	NULL	3	Using where
@@ -445,22 +445,22 @@ id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	p0,p1,p2,p3,p4	ALL	NULL	NULL	NULL	NULL	1010	
 explain partitions select * from t2 where a < 801 and a > 200;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t2	p1,p2,p3,p4	ALL	NULL	NULL	NULL	NULL	800	Using where
+1	SIMPLE	t2	p1,p2,p3,p4	ALL	NULL	NULL	NULL	NULL	1010	Using where
 explain partitions select * from t2 where a < 801 and a > 800;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t2	p4	ALL	NULL	NULL	NULL	NULL	200	Using where
+1	SIMPLE	t2	p4	ALL	NULL	NULL	NULL	NULL	1010	Using where
 explain partitions select * from t2 where a > 600;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t2	p3,p4	ALL	NULL	NULL	NULL	NULL	400	Using where
+1	SIMPLE	t2	p3,p4	ALL	NULL	NULL	NULL	NULL	1010	Using where
 explain partitions select * from t2 where a > 600 and b = 1;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t2	p3,p4	ALL	NULL	NULL	NULL	NULL	400	Using where
+1	SIMPLE	t2	p3,p4	ALL	NULL	NULL	NULL	NULL	1010	Using where
 explain partitions select * from t2 where a > 600 and b = 4;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t2	p3,p4	ALL	NULL	NULL	NULL	NULL	400	Using where
+1	SIMPLE	t2	p3,p4	ALL	NULL	NULL	NULL	NULL	1010	Using where
 explain partitions select * from t2 where a > 600 and b = 5;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t2	p3,p4	ALL	NULL	NULL	NULL	NULL	400	Using where
+1	SIMPLE	t2	p3,p4	ALL	NULL	NULL	NULL	NULL	1010	Using where
 explain partitions select * from t2 where b = 5;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	p0,p1,p2,p3,p4	ALL	NULL	NULL	NULL	NULL	1010	Using where
@@ -515,19 +515,19 @@ id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	p0,p1,p2,p3,p4	ALL	NULL	NULL	NULL	NULL	910	
 explain partitions select * from t2 where a = 101;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t2	p0	ALL	NULL	NULL	NULL	NULL	110	Using where
+1	SIMPLE	t2	p0	ALL	NULL	NULL	NULL	NULL	910	Using where
 explain partitions select * from t2 where a = 550;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t2	p2	ALL	NULL	NULL	NULL	NULL	200	Using where
+1	SIMPLE	t2	p2	ALL	NULL	NULL	NULL	NULL	910	Using where
 explain partitions select * from t2 where a = 833;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t2	p4	ALL	NULL	NULL	NULL	NULL	200	Using where
+1	SIMPLE	t2	p4	ALL	NULL	NULL	NULL	NULL	910	Using where
 explain partitions select * from t2 where (a = 100 OR a = 900);
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t2	p0,p4	ALL	NULL	NULL	NULL	NULL	310	Using where
+1	SIMPLE	t2	p0,p4	ALL	NULL	NULL	NULL	NULL	910	Using where
 explain partitions select * from t2 where (a > 100 AND a < 600);
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t2	p0,p1,p2,p3	ALL	NULL	NULL	NULL	NULL	710	Using where
+1	SIMPLE	t2	p0,p1,p2,p3	ALL	NULL	NULL	NULL	NULL	910	Using where
 explain partitions select * from t2 where b = 4;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	p0,p1,p2,p3,p4	ref	b	b	5	const	76	Using where
@@ -813,17 +813,17 @@ id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
 explain partitions select * from t1 
 where a >= 18446744073709551000-1 and a <= 18446744073709551000+1;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	p3,p4	ALL	NULL	NULL	NULL	NULL	3	Using where
+1	SIMPLE	t1	p3,p4	ALL	NULL	NULL	NULL	NULL	4	Using where
 explain partitions select * from t1 
 where a between 18446744073709551001 and 18446744073709551002;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	p4	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	SIMPLE	t1	p4	ALL	NULL	NULL	NULL	NULL	4	Using where
 explain partitions select * from t1 where a = 18446744073709551000;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	p4	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	SIMPLE	t1	p4	ALL	NULL	NULL	NULL	NULL	4	Using where
 explain partitions select * from t1 where a = 18446744073709551613;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	p4	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	SIMPLE	t1	p4	ALL	NULL	NULL	NULL	NULL	4	Using where
 explain partitions select * from t1 where a = 18446744073709551614;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
@@ -850,10 +850,10 @@ id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	p0	ALL	NULL	NULL	NULL	NULL	2	Using where
 explain partitions select * from t1 where a=0xFE;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	p2	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	SIMPLE	t1	p2	ALL	NULL	NULL	NULL	NULL	4	Using where
 explain partitions select * from t2 where a=0xFE;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t2	p2	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	SIMPLE	t2	p2	ALL	NULL	NULL	NULL	NULL	4	Using where
 explain partitions select * from t1 where a > 0xFE AND a <= 0xFF;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
@@ -862,22 +862,22 @@ id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 explain partitions select * from t1 where a >= 0xFE AND a <= 0xFF;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	p2	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	SIMPLE	t1	p2	ALL	NULL	NULL	NULL	NULL	4	Using where
 explain partitions select * from t2 where a >= 0xFE AND a <= 0xFF;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t2	p2	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	SIMPLE	t2	p2	ALL	NULL	NULL	NULL	NULL	4	Using where
 explain partitions select * from t1 where a < 64 AND a >= 63;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	p0	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	SIMPLE	t1	p0	ALL	NULL	NULL	NULL	NULL	4	Using where
 explain partitions select * from t2 where a < 64 AND a >= 63;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t2	p0	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	SIMPLE	t2	p0	ALL	NULL	NULL	NULL	NULL	4	Using where
 explain partitions select * from t1 where a <= 64 AND a >= 63;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	p0,p1	ALL	NULL	NULL	NULL	NULL	4	Using where
+1	SIMPLE	t1	p0,p1	ALL	NULL	NULL	NULL	NULL	6	Using where
 explain partitions select * from t2 where a <= 64 AND a >= 63;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t2	p0,p1	ALL	NULL	NULL	NULL	NULL	4	Using where
+1	SIMPLE	t2	p0,p1	ALL	NULL	NULL	NULL	NULL	6	Using where
 drop table t1;
 drop table t2;
 create table t1(a bigint unsigned not null) partition by range(a+0) (