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Merge ibabaev@bk-internal.mysql.com:/home/bk/mysql-5.0-opt

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into  rurik.mysql.com:/home/igor/mysql-5.0-opt
This commit is contained in:
unknown 2006-08-25 02:18:30 -07:00
commit 75865af64b
3 changed files with 135 additions and 26 deletions
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42
mysql-test/r/select.result
View File

@ -2328,9 +2328,9 @@ explain select * from t1 left join t2 on id1 = id2 left join t3 on id1 = id3
left join t4 on id3 = id4 where id2 = 1 or id4 = 1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t3 system NULL NULL NULL NULL 0 const row not found
1 SIMPLE t4 const id4 NULL NULL NULL 1
1 SIMPLE t1 ALL NULL NULL NULL NULL 2
1 SIMPLE t2 ALL NULL NULL NULL NULL 1
1 SIMPLE t4 ALL id4 NULL NULL NULL 1 Using where
1 SIMPLE t2 ALL NULL NULL NULL NULL 1 Using where
select * from t1 left join t2 on id1 = id2 left join t3 on id1 = id3
left join t4 on id3 = id4 where id2 = 1 or id4 = 1;
id1 id2 id3 id4 id44
@ -3479,3 +3479,41 @@ Warning 1466 Leading spaces are removed from name ' a '
execute stmt;
a
1
CREATE TABLE t1 (a int NOT NULL PRIMARY KEY, b int NOT NULL);
INSERT INTO t1 VALUES (1,1), (2,2), (3,3), (4,4);
CREATE TABLE t2 (c int NOT NULL, INDEX idx(c));
INSERT INTO t2 VALUES
(1), (1), (1), (1), (1), (1), (1), (1),
(2), (2), (2), (2),
(3), (3),
(4);
EXPLAIN SELECT b FROM t1, t2 WHERE b=c AND a=1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 const PRIMARY PRIMARY 4 const 1
1 SIMPLE t2 ref idx idx 4 const 7 Using index
EXPLAIN SELECT b FROM t1, t2 WHERE b=c AND a=4;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 const PRIMARY PRIMARY 4 const 1
1 SIMPLE t2 ref idx idx 4 const 1 Using index
DROP TABLE t1, t2;
CREATE TABLE t1 (id int NOT NULL PRIMARY KEY, a int);
INSERT INTO t1 VALUES (1,2), (2,NULL), (3,2);
CREATE TABLE t2 (b int, c INT, INDEX idx1(b));
INSERT INTO t2 VALUES (2,1), (3,2);
CREATE TABLE t3 (d int, e int, INDEX idx1(d));
INSERT INTO t3 VALUES (2,10), (2,20), (1,30), (2,40), (2,50);
EXPLAIN
SELECT * FROM t1 LEFT JOIN t2 ON t2.b=t1.a INNER JOIN t3 ON t3.d=t1.id
WHERE t1.id=2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 const PRIMARY PRIMARY 4 const 1
1 SIMPLE t2 const idx1 NULL NULL NULL 1
1 SIMPLE t3 ref idx1 idx1 5 const 3 Using where
SELECT * FROM t1 LEFT JOIN t2 ON t2.b=t1.a INNER JOIN t3 ON t3.d=t1.id
WHERE t1.id=2;
id a b c d e
2 NULL NULL NULL 2 10
2 NULL NULL NULL 2 20
2 NULL NULL NULL 2 40
2 NULL NULL NULL 2 50
DROP TABLE t1,t2,t3;

41
mysql-test/t/select.test
View File

@ -2957,3 +2957,44 @@ SELECT 0.9888889889 * 1.011111411911;
#
prepare stmt from 'select 1 as " a "';
execute stmt;
#
# Bug #21390: wrong estimate of rows after elimination of const tables
#
CREATE TABLE t1 (a int NOT NULL PRIMARY KEY, b int NOT NULL);
INSERT INTO t1 VALUES (1,1), (2,2), (3,3), (4,4);
CREATE TABLE t2 (c int NOT NULL, INDEX idx(c));
INSERT INTO t2 VALUES
(1), (1), (1), (1), (1), (1), (1), (1),
(2), (2), (2), (2),
(3), (3),
(4);
EXPLAIN SELECT b FROM t1, t2 WHERE b=c AND a=1;
EXPLAIN SELECT b FROM t1, t2 WHERE b=c AND a=4;
DROP TABLE t1, t2;
#
# No matches for a join after substitution of a const table
#
CREATE TABLE t1 (id int NOT NULL PRIMARY KEY, a int);
INSERT INTO t1 VALUES (1,2), (2,NULL), (3,2);
CREATE TABLE t2 (b int, c INT, INDEX idx1(b));
INSERT INTO t2 VALUES (2,1), (3,2);
CREATE TABLE t3 (d int, e int, INDEX idx1(d));
INSERT INTO t3 VALUES (2,10), (2,20), (1,30), (2,40), (2,50);
EXPLAIN
SELECT * FROM t1 LEFT JOIN t2 ON t2.b=t1.a INNER JOIN t3 ON t3.d=t1.id
WHERE t1.id=2;
SELECT * FROM t1 LEFT JOIN t2 ON t2.b=t1.a INNER JOIN t3 ON t3.d=t1.id
WHERE t1.id=2;
DROP TABLE t1,t2,t3;

38
sql/sql_select.cc
View File

@ -2205,6 +2205,7 @@ make_join_statistics(JOIN *join, TABLE_LIST *tables, COND *conds,
int ref_changed;
do
{
more_const_tables_found:
ref_changed = 0;
found_ref=0;
@ -2216,6 +2217,30 @@ make_join_statistics(JOIN *join, TABLE_LIST *tables, COND *conds,
for (JOIN_TAB **pos=stat_vector+const_count ; (s= *pos) ; pos++)
{
table=s->table;
/*
If equi-join condition by a key is null rejecting and after a
substitution of a const table the key value happens to be null
then we can state that there are no matches for this equi-join.
*/
if ((keyuse= s->keyuse) && *s->on_expr_ref)
{
while (keyuse->table == table)
{
if (!(keyuse->val->used_tables() & ~join->const_table_map) &&
keyuse->val->is_null() && keyuse->null_rejecting)
{
s->type= JT_CONST;
mark_as_null_row(table);
found_const_table_map|= table->map;
join->const_table_map|= table->map;
set_position(join,const_count++,s,(KEYUSE*) 0);
goto more_const_tables_found;
}
keyuse++;
}
}
if (s->dependent) // If dependent on some table
{
// All dep. must be constants
@ -2266,10 +2291,11 @@ make_join_statistics(JOIN *join, TABLE_LIST *tables, COND *conds,
} while (keyuse->table == table && keyuse->key == key);
if (eq_part.is_prefix(table->key_info[key].key_parts) &&
((table->key_info[key].flags & (HA_NOSAME | HA_END_SPACE_KEY)) ==
HA_NOSAME) &&
!table->fulltext_searched &&
!table->pos_in_table_list->embedding)
{
if ((table->key_info[key].flags & (HA_NOSAME | HA_END_SPACE_KEY))
== HA_NOSAME)
{
if (const_ref == eq_part)
{ // Found everything for ref.
@ -2294,6 +2320,9 @@ make_join_statistics(JOIN *join, TABLE_LIST *tables, COND *conds,
else
found_ref|= refs; // Table is const if all refs are const
}
else if (const_ref == eq_part)
s->const_keys.set_bit(key);
}
}
}
}
@ -2696,7 +2725,8 @@ add_key_field(KEY_FIELD **key_fields,uint and_level, Item_func *cond,
We use null_rejecting in add_not_null_conds() to add
'othertbl.field IS NOT NULL' to tab->select_cond.
*/
(*key_fields)->null_rejecting= ((cond->functype() == Item_func::EQ_FUNC) &&
(*key_fields)->null_rejecting= ((cond->functype() == Item_func::EQ_FUNC ||
cond->functype() == Item_func::MULT_EQUAL_FUNC) &&
((*value)->type() == Item::FIELD_ITEM) &&
((Item_field*)*value)->field->maybe_null());
(*key_fields)++;
@ -3461,7 +3491,7 @@ best_access_path(JOIN *join,
keyuse->used_tables));
if (tmp < best_prev_record_reads)
{
best_part_found_ref= keyuse->used_tables;
best_part_found_ref= keyuse->used_tables & ~join->const_table_map;
best_prev_record_reads= tmp;
}
if (rec > keyuse->ref_table_rows)