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Fixed the bug mdev-13193.

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When an equality that can be pushed into a materialized derived
table / view is extracted from multiple equalities and their
operands are cloned then if they have some pointers to Item_equal
objects those pointers must be set to NULL in the clones. Anyway
they are not valid in the pushed predicates.
This commit is contained in:
Igor Babaev 2017-06-29 20:50:07 -07:00
commit 9f0c1c0cf6
4 changed files with 84 additions and 1 deletions
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57
mysql-test/r/derived_cond_pushdown.result
View file

@ -8709,3 +8709,60 @@ EXPLAIN
}
DROP VIEW v1;
DROP TABLE t1;
#
# MDEV-13193: pushdown of equality extracted from multiple equality
#
CREATE TABLE t1 (i1 int, KEY(i1)) ENGINE=MyISAM;
INSERT INTO t1 VALUES (1),(2);
CREATE TABLE t2 (i2 int) ENGINE=MyISAM;
INSERT INTO t2 VALUES (2),(4);
CREATE ALGORITHM=TEMPTABLE VIEW v2 AS SELECT * FROM t2;
SELECT * FROM t1, ( SELECT * FROM v2 ) AS sq
WHERE i1 = 1 AND ( i1 = i2 OR i1 = 2 );
i1 i2
explain format=json SELECT * FROM t1, ( SELECT * FROM v2 ) AS sq
WHERE i1 = 1 AND ( i1 = i2 OR i1 = 2 );
EXPLAIN
{
"query_block": {
"select_id": 1,
"table": {
"table_name": "t1",
"access_type": "ref",
"possible_keys": ["i1"],
"key": "i1",
"key_length": "5",
"used_key_parts": ["i1"],
"ref": ["const"],
"rows": 1,
"filtered": 100,
"using_index": true
},
"block-nl-join": {
"table": {
"table_name": "<derived3>",
"access_type": "ALL",
"rows": 2,
"filtered": 100,
"attached_condition": "v2.i2 = 1"
},
"buffer_type": "flat",
"buffer_size": "256Kb",
"join_type": "BNL",
"materialized": {
"query_block": {
"select_id": 3,
"table": {
"table_name": "t2",
"access_type": "ALL",
"rows": 2,
"filtered": 100,
"attached_condition": "t2.i2 = 1"
}
}
}
}
}
}
DROP VIEW v2;
DROP TABLE t1,t2;

2
mysql-test/r/derived_view.result
View file

@ -1107,7 +1107,7 @@ id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 system NULL NULL NULL NULL 1
1 PRIMARY t2 ref a a 4 const 1 Using index
1 PRIMARY <derived2> ref key0 key0 8 const,const 1
2 DERIVED t3 ALL NULL NULL NULL NULL 12 Using where; Using temporary; Using filesort
2 DERIVED t3 ALL NULL NULL NULL NULL 12 Using temporary; Using filesort
SELECT * FROM t1, t2, v1 WHERE t2.a=t1.a AND t2.a=v1.a AND t2.a=v1.b;
a a a b
c c c c

22
mysql-test/t/derived_cond_pushdown.test
View file

@ -1526,3 +1526,25 @@ eval explain format=json $q;
DROP VIEW v1;
DROP TABLE t1;
--echo #
--echo # MDEV-13193: pushdown of equality extracted from multiple equality
--echo #
CREATE TABLE t1 (i1 int, KEY(i1)) ENGINE=MyISAM;
INSERT INTO t1 VALUES (1),(2);
CREATE TABLE t2 (i2 int) ENGINE=MyISAM;
INSERT INTO t2 VALUES (2),(4);
CREATE ALGORITHM=TEMPTABLE VIEW v2 AS SELECT * FROM t2;
let $q=
SELECT * FROM t1, ( SELECT * FROM v2 ) AS sq
WHERE i1 = 1 AND ( i1 = i2 OR i1 = 2 );
eval $q;
eval explain format=json $q;
DROP VIEW v2;
DROP TABLE t1,t2;

4
sql/table.cc
View file

@ -8237,8 +8237,12 @@ Item* TABLE_LIST::build_pushable_cond_for_table(THD *thd, Item *cond)
Item *left_item_clone= left_item->build_clone(thd, thd->mem_root);
Item *right_item_clone= item->build_clone(thd, thd->mem_root);
if (left_item_clone && right_item_clone)
{
left_item_clone->set_item_equal(NULL);
right_item_clone->set_item_equal(NULL);
eq= new (thd->mem_root) Item_func_eq(thd, right_item_clone,
left_item_clone);
}
if (eq)
{
i++;