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bug#28570: handler::index_read() is called with different find_flag when

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ORDER BY is used

The range analysis module did not correctly signal to the 
handler that a range represents a ref (EQ_RANGE flag). This causes 
non-range queries like 
SELECT ... FROM ... WHERE keypart_1=const, ..., keypart_n=const 
ORDER BY ... FOR UPDATE
to wait for a lock unneccesarily if another running transaction uses
SELECT ... FOR UPDATE on the same table.

Fixed by setting EQ_RANGE for all range accesses that represent 
an equality predicate. 


mysql-test/r/innodb_mysql.result:
  bug#28570: Test Result
mysql-test/t/innodb_mysql.test:
  bug#28570: Test Case
sql/handler.cc:
  bug#28570: Updated comment
sql/opt_range.cc:
  bug#28570: Removed the criterion that key has to be unique (HA_NOSAME) in 
  order for the EQ_RANGE flag to be set. It is sufficient that the range 
  represent a ref access.
This commit is contained in:
unknown 2007-08-15 09:23:44 +02:00
parent 1f83b35181
commit 01f8130aa6
4 changed files with 50 additions and 3 deletions
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18
mysql-test/r/innodb_mysql.result
View File

@ -1007,4 +1007,22 @@ CALL p1();
CALL p1();
DROP PROCEDURE p1;
DROP TABLE t1;
CREATE TABLE t1 (
a INT,
b INT,
KEY (b)
) ENGINE=InnoDB;
INSERT INTO t1 VALUES (1,10), (2,10), (2,20), (3,30);
START TRANSACTION;
SELECT * FROM t1 WHERE b=20 FOR UPDATE;
a b
2 20
START TRANSACTION;
SELECT * FROM t1 WHERE b=10 ORDER BY A FOR UPDATE;
a b
1 10
2 10
ROLLBACK;
ROLLBACK;
DROP TABLE t1;
End of 5.0 tests

29
mysql-test/t/innodb_mysql.test
View File

@ -840,5 +840,34 @@ DISCONNECT con2;
DROP PROCEDURE p1;
DROP TABLE t1;
#
# Bug #28570: handler::index_read() is called with different find_flag when
# ORDER BY is used
#
CREATE TABLE t1 (
a INT,
b INT,
KEY (b)
) ENGINE=InnoDB;
INSERT INTO t1 VALUES (1,10), (2,10), (2,20), (3,30);
START TRANSACTION;
SELECT * FROM t1 WHERE b=20 FOR UPDATE;
--connect (conn2, localhost, root,,test)
# This statement gives a "failed: 1205: Lock wait timeout exceeded; try
# restarting transaction" message when the bug is present.
START TRANSACTION;
SELECT * FROM t1 WHERE b=10 ORDER BY A FOR UPDATE;
ROLLBACK;
--disconnect conn2
--connection default
ROLLBACK;
DROP TABLE t1;
--echo End of 5.0 tests

3
sql/handler.cc
View File

@ -2610,7 +2610,8 @@ int handler::read_multi_range_next(KEY_MULTI_RANGE **found_range_p)
read_range_first()
start_key Start key. Is 0 if no min range
end_key End key. Is 0 if no max range
eq_range_arg Set to 1 if start_key == end_key
eq_range_arg Set to 1 if start_key == end_key and the range endpoints
will not change during query execution.
sorted Set to 1 if result should be sorted per key
NOTES

3
sql/opt_range.cc
View File

@ -6369,8 +6369,7 @@ QUICK_RANGE_SELECT *get_quick_select_for_ref(THD *thd, TABLE *table,
range->min_key=range->max_key=(char*) ref->key_buff;
range->min_length=range->max_length=ref->key_length;
range->flag= ((ref->key_length == key_info->key_length &&
(key_info->flags & (HA_NOSAME | HA_END_SPACE_KEY)) ==
HA_NOSAME) ? EQ_RANGE : 0);
(key_info->flags & HA_END_SPACE_KEY) == 0) ? EQ_RANGE : 0);
if (!(quick->key_parts=key_part=(KEY_PART *)
alloc_root(&quick->alloc,sizeof(KEY_PART)*ref->key_parts)))