Commit ee5795f2 authored by unknown's avatar unknown
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Fix bug#13327 check_equality() wasn't checking view's fields 

check_equality() finds equalities among field items. It checks input items
to be Item_fields thus skipping view's fields, which are represented by
Item_direct_view_ref. Because of this index wasn't applied in all cases
it can be.

To fix this problem check_equality() now takes real item of
Item_direct_view_ref, except outer view refs (with depended_from set).


sql/sql_select.cc:
  Fix bug #13327 VIEW performs index scan
   For proper views fields handling check_equality() now takes real item from Item_direct_view_ref, with exception of outer view refs.
mysql-test/r/view.result:
  Test case for bug#13327 VIEW performs index scan
mysql-test/t/view.test:
  Test case for bug#13327 VIEW performs index scan
parent 20a6f152

mysql-test/r/view.result

+22 −0
Original line number Diff line number Diff line
@@ -2298,3 +2298,25 @@ a 
3

DROP VIEW v1;

DROP TABLE t1;

CREATE TABLE t1 (a INT, b INT, INDEX(a,b));

CREATE TABLE t2 LIKE t1;

CREATE TABLE t3 (a INT);

INSERT INTO t1 VALUES (1,1),(2,2),(3,3);

INSERT INTO t2 VALUES (1,1),(2,2),(3,3);

INSERT INTO t3 VALUES (1),(2),(3);

CREATE VIEW v1 AS SELECT t1.* FROM t1,t2 WHERE t1.a=t2.a AND t1.b=t2.b;

CREATE VIEW v2 AS SELECT t3.* FROM t1,t3 WHERE t1.a=t3.a;

EXPLAIN SELECT t1.* FROM t1 JOIN t2 WHERE t1.a=t2.a AND t1.b=t2.b AND t1.a=1;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t1	ref	a	a	5	const	1	Using where; Using index

1	SIMPLE	t2	ref	a	a	10	const,test.t1.b	2	Using where; Using index

EXPLAIN SELECT * FROM v1 WHERE a=1;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	PRIMARY	t1	ref	a	a	5	const	1	Using where; Using index

1	PRIMARY	t2	ref	a	a	10	const,test.t1.b	2	Using where; Using index

EXPLAIN SELECT * FROM v2 WHERE a=1;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	PRIMARY	t1	ref	a	a	5	const	1	Using where; Using index

1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	Using where

DROP VIEW v1,v2;

DROP TABLE t1,t2,t3;

mysql-test/t/view.test

+20 −0
Original line number Diff line number Diff line
@@ -2167,3 +2167,23 @@ SELECT v_1.a FROM v1 AS v_1 GROUP BY v_1.a HAVING v_1.a IN (1,2,3); 


DROP VIEW v1;

DROP TABLE t1;



#

# Bug #13327 view wasn't using index for const condition

#



CREATE TABLE t1 (a INT, b INT, INDEX(a,b));

CREATE TABLE t2 LIKE t1;

CREATE TABLE t3 (a INT);

INSERT INTO t1 VALUES (1,1),(2,2),(3,3);

INSERT INTO t2 VALUES (1,1),(2,2),(3,3);

INSERT INTO t3 VALUES (1),(2),(3);

CREATE VIEW v1 AS SELECT t1.* FROM t1,t2 WHERE t1.a=t2.a AND t1.b=t2.b;

CREATE VIEW v2 AS SELECT t3.* FROM t1,t3 WHERE t1.a=t3.a;

EXPLAIN SELECT t1.* FROM t1 JOIN t2 WHERE t1.a=t2.a AND t1.b=t2.b AND t1.a=1;

EXPLAIN SELECT * FROM v1 WHERE a=1;

EXPLAIN SELECT * FROM v2 WHERE a=1;

DROP VIEW v1,v2;

DROP TABLE t1,t2,t3;

sql/sql_select.cc

+15 −0
Original line number Diff line number Diff line
@@ -6254,6 +6254,21 @@ static bool check_equality(Item *item, COND_EQUAL *cond_equal) 
  {

    Item *left_item= ((Item_func*) item)->arguments()[0];

    Item *right_item= ((Item_func*) item)->arguments()[1];



    if (left_item->type() == Item::REF_ITEM &&

        ((Item_ref*)left_item)->ref_type() == Item_ref::VIEW_REF)

    {

      if (((Item_ref*)left_item)->depended_from)

        return FALSE;

      left_item= left_item->real_item();

    }

    if (right_item->type() == Item::REF_ITEM &&

        ((Item_ref*)right_item)->ref_type() == Item_ref::VIEW_REF)

    {

      if (((Item_ref*)right_item)->depended_from)

        return FALSE;

      right_item= right_item->real_item();

    }

    if (left_item->type() == Item::FIELD_ITEM &&

        right_item->type() == Item::FIELD_ITEM &&

        !((Item_field*)left_item)->depended_from &&