Commit 8bba9089 authored by sergefp@mysql.com's avatar sergefp@mysql.com

BUG#29740: Wrong query results for index_merge/union over HEAP table.

- return HA_KEY_SCAN_NOT_ROR flag for HASH indexes;
- Fix ha_heap::cmp_ref() to work with BTREE index scans.
parent b7bb96dd
......@@ -455,3 +455,64 @@ a
1
UNLOCK TABLES;
DROP TABLE t1, t2;
CREATE TABLE `t1` (
`a` int(11) DEFAULT NULL,
`filler` char(200) DEFAULT NULL,
`b` int(11) DEFAULT NULL,
KEY `a` (`a`),
KEY `b` (`b`)
) ENGINE=MEMORY DEFAULT CHARSET=latin1;
insert into t1 values
(0, 'filler', 0), (1, 'filler', 1), (2, 'filler', 2), (3, 'filler', 3),
(4, 'filler', 4), (5, 'filler', 5), (6, 'filler', 6), (7, 'filler', 7),
(8, 'filler', 8), (9, 'filler', 9), (0, 'filler', 0), (1, 'filler', 1),
(2, 'filler', 2), (3, 'filler', 3), (4, 'filler', 4), (5, 'filler', 5),
(6, 'filler', 6), (7, 'filler', 7), (8, 'filler', 8), (9, 'filler', 9),
(10, 'filler', 10), (11, 'filler', 11), (12, 'filler', 12), (13, 'filler', 13),
(14, 'filler', 14), (15, 'filler', 15), (16, 'filler', 16), (17, 'filler', 17),
(18, 'filler', 18), (19, 'filler', 19), (4, '5 ', 0), (5, '4 ', 0),
(4, '4 ', 0), (4, 'qq ', 5), (5, 'qq ', 4), (4, 'zz ', 4);
create table t2(
`a` int(11) DEFAULT NULL,
`filler` char(200) DEFAULT NULL,
`b` int(11) DEFAULT NULL,
KEY USING BTREE (`a`),
KEY USING BTREE (`b`)
) ENGINE=MEMORY DEFAULT CHARSET=latin1;
insert into t2 select * from t1;
must use sort-union rather than union:
explain select * from t1 where a=4 or b=4;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index_merge a,b a,b 5,5 NULL 4 Using sort_union(a,b); Using where
select * from t1 where a=4 or b=4;
a filler b
4 zz 4
5 qq 4
4 filler 4
4 qq 5
4 4 0
4 filler 4
4 5 0
select * from t1 ignore index(a,b) where a=4 or b=4;
a filler b
4 filler 4
4 filler 4
4 5 0
4 4 0
4 qq 5
5 qq 4
4 zz 4
must use union, not sort-union:
explain select * from t2 where a=4 or b=4;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 index_merge a,b a,b 5,5 NULL 7 Using union(a,b); Using where
select * from t2 where a=4 or b=4;
a filler b
4 5 0
4 zz 4
5 qq 4
4 filler 4
4 qq 5
4 4 0
4 filler 4
drop table t1, t2;
......@@ -415,3 +415,46 @@ INSERT INTO t2(a,b) VALUES(1,2);
SELECT t2.a FROM t1,t2 WHERE t2.b=2 AND t2.a=1;
UNLOCK TABLES;
DROP TABLE t1, t2;
#
# BUG#29740: HA_KEY_SCAN_NOT_ROR wasn't set for HEAP engine
#
CREATE TABLE `t1` (
`a` int(11) DEFAULT NULL,
`filler` char(200) DEFAULT NULL,
`b` int(11) DEFAULT NULL,
KEY `a` (`a`),
KEY `b` (`b`)
) ENGINE=MEMORY DEFAULT CHARSET=latin1;
insert into t1 values
(0, 'filler', 0), (1, 'filler', 1), (2, 'filler', 2), (3, 'filler', 3),
(4, 'filler', 4), (5, 'filler', 5), (6, 'filler', 6), (7, 'filler', 7),
(8, 'filler', 8), (9, 'filler', 9), (0, 'filler', 0), (1, 'filler', 1),
(2, 'filler', 2), (3, 'filler', 3), (4, 'filler', 4), (5, 'filler', 5),
(6, 'filler', 6), (7, 'filler', 7), (8, 'filler', 8), (9, 'filler', 9),
(10, 'filler', 10), (11, 'filler', 11), (12, 'filler', 12), (13, 'filler', 13),
(14, 'filler', 14), (15, 'filler', 15), (16, 'filler', 16), (17, 'filler', 17),
(18, 'filler', 18), (19, 'filler', 19), (4, '5 ', 0), (5, '4 ', 0),
(4, '4 ', 0), (4, 'qq ', 5), (5, 'qq ', 4), (4, 'zz ', 4);
create table t2(
`a` int(11) DEFAULT NULL,
`filler` char(200) DEFAULT NULL,
`b` int(11) DEFAULT NULL,
KEY USING BTREE (`a`),
KEY USING BTREE (`b`)
) ENGINE=MEMORY DEFAULT CHARSET=latin1;
insert into t2 select * from t1;
--echo must use sort-union rather than union:
explain select * from t1 where a=4 or b=4;
select * from t1 where a=4 or b=4;
select * from t1 ignore index(a,b) where a=4 or b=4;
--echo must use union, not sort-union:
explain select * from t2 where a=4 or b=4;
select * from t2 where a=4 or b=4;
drop table t1, t2;
......@@ -55,7 +55,7 @@ public:
{
return ((table->key_info[inx].algorithm == HA_KEY_ALG_BTREE) ?
HA_READ_NEXT | HA_READ_PREV | HA_READ_ORDER | HA_READ_RANGE :
HA_ONLY_WHOLE_INDEX);
HA_ONLY_WHOLE_INDEX | HA_KEY_SCAN_NOT_ROR);
}
const key_map *keys_to_use_for_scanning() { return &btree_keys; }
uint max_supported_keys() const { return MAX_KEY; }
......@@ -101,9 +101,7 @@ public:
enum thr_lock_type lock_type);
int cmp_ref(const byte *ref1, const byte *ref2)
{
HEAP_PTR ptr1=*(HEAP_PTR*)ref1;
HEAP_PTR ptr2=*(HEAP_PTR*)ref2;
return ptr1 < ptr2? -1 : (ptr1 > ptr2? 1 : 0);
return memcmp(ref1, ref2, sizeof(HEAP_PTR));
}
private:
void update_key_stats();
......
......@@ -6007,27 +6007,24 @@ check_quick_keys(PARAM *param,uint idx,SEL_ARG *key_tree,
ROR (Rowid Ordered Retrieval) key scan is a key scan that produces
ordered sequence of rowids (ha_xxx::cmp_ref is the comparison function)
An index scan is a ROR scan if it is done using a condition in form
This function is needed to handle a practically-important special case:
an index scan is a ROR scan if it is done using a condition in form
"key1_1=c_1 AND ... AND key1_n=c_n" (1)
"key1_1=c_1 AND ... AND key1_n=c_n"
where the index is defined on (key1_1, ..., key1_N [,a_1, ..., a_n])
and the table has a clustered Primary Key
and the table has a clustered Primary Key defined as
PRIMARY KEY(a_1, ..., a_n, b1, ..., b_k) with first key parts being
identical to uncovered parts ot the key being scanned (2)
PRIMARY KEY(a_1, ..., a_n, b1, ..., b_k)
Scans on HASH indexes are not ROR scans,
any range scan on clustered primary key is ROR scan (3)
Check (1) is made in check_quick_keys()
Check (3) is made check_quick_select()
Check (2) is made by this function.
i.e. the first key parts of it are identical to uncovered parts ot the
key being scanned. This function assumes that the index flags do not
include HA_KEY_SCAN_NOT_ROR flag (that is checked elsewhere).
RETURN
TRUE If the scan is ROR-scan
FALSE otherwise
TRUE The scan is ROR-scan
FALSE Otherwise
*/
static bool is_key_scan_ror(PARAM *param, uint keynr, uint8 nparts)
......
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