From 38f4c6137a64192a962ad9d357055ced0f9150fa Mon Sep 17 00:00:00 2001
From: unknown <sergefp@mysql.com>
Date: Fri, 13 Jul 2007 19:13:40 +0400
Subject: [PATCH] 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.
mysql-test/r/index_merge.result:
BUG#29740: testcase
mysql-test/t/index_merge.test:
BUG#29740: testcase
sql/ha_heap.h:
BUG#29740: Wrong query results for index_merge/union over HEAP table.
- make HEAP table engine return HA_KEY_SCAN_NOT_ROR flag for HASH
indexes,as HASH index does not guarantee any ordering for rows
within the hash bucket.
- Fix BTREE indexes: make ha_heap::cmp_ref() compare the rowids in the
same way as ha_key_cmp() does.
sql/opt_range.cc:
BUG#29740: Fix comment about ROR scans.
---
mysql-test/r/index_merge.result | 61 +++++++++++++++++++++++++++++++++
mysql-test/t/index_merge.test | 43 +++++++++++++++++++++++
sql/ha_heap.h | 8 ++---
sql/opt_range.cc | 25 ++++++--------
4 files changed, 118 insertions(+), 19 deletions(-)
diff --git a/mysql-test/r/index_merge.result b/mysql-test/r/index_merge.result
index 9456b4ec978..c7e4ead9eeb 100644
--- a/mysql-test/r/index_merge.result
+++ b/mysql-test/r/index_merge.result
@@ -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;
diff --git a/mysql-test/t/index_merge.test b/mysql-test/t/index_merge.test
index 30eb0b40fca..7d9a4340b0f 100644
--- a/mysql-test/t/index_merge.test
+++ b/mysql-test/t/index_merge.test
@@ -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;
+
diff --git a/sql/ha_heap.h b/sql/ha_heap.h
index 18389c1298d..27846ca4a8e 100644
--- a/sql/ha_heap.h
+++ b/sql/ha_heap.h
@@ -54,8 +54,8 @@ class ha_heap: public handler
ulong index_flags(uint inx, uint part, bool all_parts) const
{
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_READ_NEXT | HA_READ_PREV | HA_READ_ORDER | HA_READ_RANGE :
+ 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 @@ class ha_heap: public handler
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();
diff --git a/sql/opt_range.cc b/sql/opt_range.cc
index c3aa1f52556..952e5abfd13 100644
--- a/sql/opt_range.cc
+++ b/sql/opt_range.cc
@@ -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)
-
- 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.
+ PRIMARY KEY(a_1, ..., a_n, b1, ..., b_k)
+
+ 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)
--
2.30.9