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Bug#50402 Optimizer producing wrong results when using Index Merge on InnoDB

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Subselect executes twice, at JOIN::optimize stage
and at JOIN::execute stage. At optimize stage
Innodb prebuilt struct which is used for the
retrieval of column values is initialized in.
ha_innobase::index_read(), prebuilt->sql_stat_start is true.
After QUICK_ROR_INTERSECT_SELECT finished his job it
restores read_set/write_set bitmaps with initial values
and deactivates one of the handlers used by
QUICK_ROR_INTERSECT_SELECT in JOIN::cleanup
(it's the case when we reuse original handler as one of
 handlers required by QUICK_ROR_INTERSECT_SELECT object).
On second subselect execution inactive handler is activated
in  QUICK_RANGE_SELECT::reset, file->ha_index_init().
In ha_index_init Innodb prebuilt struct is reinitialized
with inappropriate read_set/write_set bitmaps. Further
reinitialization in ha_innobase::index_read() does not
happen as prebuilt->sql_stat_start is false.
It leads to partial retrieval of required field values
and we get a mix of field values from different records
in the record buffer.
The fix is to reset
read_set/write_set bitmaps as these values
are required for proper intialization of
internal InnoDB struct which is used for
the retrieval of column values
(see build_template(), ha_innodb.cc)


mysql-test/include/index_merge_ror_cpk.inc:
  test case
mysql-test/r/index_merge_innodb.result:
  test case
mysql-test/r/index_merge_myisam.result:
  test case
sql/opt_range.cc:
  if ROR merge scan is used we need to reset
  read_set/write_set bitmaps as these values
  are required for proper intialization of
  internal InnoDB struct which is used for
  the retrieval of column values
  (see build_template(), ha_innodb.cc)
This commit is contained in:
Sergey Glukhov
2010-09-16 16:13:53 +04:00
parent ebd207baa8
commit 31a38c0fc5
4 changed files with 60 additions and 3 deletions
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16
mysql-test/include/index_merge_ror_cpk.inc
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@ -126,3 +126,19 @@ WHERE
drop table t1;
--echo #
--echo # Bug#50402 Optimizer producing wrong results when using Index Merge on InnoDB
--echo #
CREATE TABLE t1 (f1 INT, PRIMARY KEY (f1));
INSERT INTO t1 VALUES (2);
CREATE TABLE t2 (f1 INT, f2 INT, f3 char(1),
PRIMARY KEY (f1), KEY (f2), KEY (f3) );
INSERT INTO t2 VALUES (1, 1, 'h'), (2, 3, 'h'), (3, 2, ''), (4, 2, '');
SELECT t1.f1 FROM t1
WHERE (SELECT COUNT(*) FROM t2 WHERE t2.f3 = 'h' AND t2.f2 = t1.f1) = 0 AND t1.f1 = 2;
EXPLAIN SELECT t1.f1 FROM t1
WHERE (SELECT COUNT(*) FROM t2 WHERE t2.f3 = 'h' AND t2.f2 = t1.f1) = 0 AND t1.f1 = 2;
DROP TABLE t1,t2;