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Merge magare.gmz:/home/kgeorge/mysql/work/B22855-5.0-opt

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into  magare.gmz:/home/kgeorge/mysql/work/B22855-5.1-opt


mysql-test/r/subselect3.result:
  Auto merged
sql/item_subselect.cc:
  Auto merged
This commit is contained in:
unknown
2007-05-21 10:22:44 +03:00
parent 2626eabc71 330a82f066
commit 4b4823bea0
3 changed files with 110 additions and 7 deletions
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18
mysql-test/r/subselect3.result
View File

@ -742,3 +742,21 @@ x
0
0
DROP TABLE t1,t2,t3;
CREATE TABLE t1 (a INT NOT NULL);
INSERT INTO t1 VALUES (1),(-1), (65),(66);
CREATE TABLE t2 (a INT UNSIGNED NOT NULL PRIMARY KEY);
INSERT INTO t2 VALUES (65),(66);
SELECT a FROM t1 WHERE a NOT IN (65,66);
a
1
-1
SELECT a FROM t1 WHERE a NOT IN (SELECT a FROM t2);
a
1
-1
EXPLAIN SELECT a FROM t1 WHERE a NOT IN (SELECT a FROM t2);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 4 Using where
2 DEPENDENT SUBQUERY t2 unique_subquery PRIMARY PRIMARY 4 func 1 Using index
DROP TABLE t1;
End of 5.0 tests

18
mysql-test/t/subselect3.test
View File

@ -571,3 +571,21 @@ SELECT (t1.id IN (SELECT t2.id FROM t2,t3
FROM t1;
DROP TABLE t1,t2,t3;
#
# Bug #22855: Optimizer doesn't rewrite NOT IN subselects to a correlated
# subquery
#
CREATE TABLE t1 (a INT NOT NULL);
INSERT INTO t1 VALUES (1),(-1), (65),(66);
CREATE TABLE t2 (a INT UNSIGNED NOT NULL PRIMARY KEY);
INSERT INTO t2 VALUES (65),(66);
SELECT a FROM t1 WHERE a NOT IN (65,66);
SELECT a FROM t1 WHERE a NOT IN (SELECT a FROM t2);
EXPLAIN SELECT a FROM t1 WHERE a NOT IN (SELECT a FROM t2);
DROP TABLE t1;
--echo End of 5.0 tests

81
sql/item_subselect.cc
View File

@ -818,6 +818,11 @@ bool Item_in_subselect::val_bool()
if (exec())
{
reset();
/*
Must mark the IN predicate as NULL so as to make sure an enclosing NOT
predicate will return FALSE. See the comments in
subselect_uniquesubquery_engine::copy_ref_key for further details.
*/
null_value= 1;
return 0;
}
@ -1979,10 +1984,38 @@ int subselect_uniquesubquery_engine::scan_table()
DESCRIPTION
Copy ref key and check for null parts in it.
Depending on the nullability and conversion problems this function
recognizes and processes the following states :
1. Partial match on top level. This means IN has a value of FALSE
regardless of the data in the subquery table.
Detected by finding a NULL in the left IN operand of a top level
expression.
We may actually skip reading the subquery, so return TRUE to skip
the table scan in subselect_uniquesubquery_engine::exec and make
the value of the IN predicate a NULL (that is equal to FALSE on
top level).
2. No exact match when IN is nested inside another predicate.
Detected by finding a NULL in the left IN operand when IN is not
a top level predicate.
We cannot have an exact match. But we must proceed further with a
table scan to find out if it's a partial match (and IN has a value
of NULL) or no match (and IN has a value of FALSE).
So we return FALSE to continue with the scan and see if there are
any record that would constitute a partial match (as we cannot
determine that from the index).
3. Error converting the left IN operand to the column type of the
right IN operand. This counts as no match (and IN has the value of
FALSE). We mark the subquery table cursor as having no more rows
(to ensure that the processing that follows will not find a match)
and return FALSE, so IN is not treated as returning NULL.
RETURN
FALSE - ok, index lookup key without keys copied.
TRUE - an error occured while copying the key
FALSE - The value of the IN predicate is not known. Proceed to find the
value of the IN predicate using the determined values of
null_keypart and table->status.
TRUE - IN predicate has a value of NULL. Stop the processing right there
and return NULL to the outer predicates.
*/
bool subselect_uniquesubquery_engine::copy_ref_key()
@ -2002,14 +2035,38 @@ bool subselect_uniquesubquery_engine::copy_ref_key()
function.
*/
null_keypart= (*copy)->null_key;
bool top_level= ((Item_in_subselect *) item)->is_top_level_item();
if (null_keypart && !top_level)
break;
if ((tab->ref.key_err) & 1 || (null_keypart && top_level))
if (null_keypart)
{
tab->table->status= STATUS_NOT_FOUND;
bool top_level= ((Item_in_subselect *) item)->is_top_level_item();
if (top_level)
{
/* Partial match on top level */
DBUG_RETURN(1);
}
else
{
/* No exact match when IN is nested inside another predicate */
break;
}
}
/*
Check if the error is equal to STORE_KEY_FATAL. This is not expressed
using the store_key::store_key_result enum because ref.key_err is a
boolean and we want to detect both TRUE and STORE_KEY_FATAL from the
space of the union of the values of [TRUE, FALSE] and
store_key::store_key_result.
TODO: fix the variable an return types.
*/
if (tab->ref.key_err & 1)
{
/*
Error converting the left IN operand to the column type of the right
IN operand.
*/
tab->table->status= STATUS_NOT_FOUND;
break;
}
}
DBUG_RETURN(0);
}
@ -2051,10 +2108,20 @@ int subselect_uniquesubquery_engine::exec()
int error;
TABLE *table= tab->table;
empty_result_set= TRUE;
table->status= 0;
/* TODO: change to use of 'full_scan' here? */
if (copy_ref_key())
DBUG_RETURN(1);
if (table->status)
{
/*
We know that there will be no rows even if we scan.
Can be set in copy_ref_key.
*/
((Item_in_subselect *) item)->value= 0;
DBUG_RETURN(0);
}
if (null_keypart)
DBUG_RETURN(scan_table());