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Bug #22781: SQL_BIG_RESULT fails to influence sort plan

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Currently SQL_BIG_RESULT is checked only at compile time.
 However, additional optimizations may take place after
 this check that change the sort method from 'filesort'
 to sorting via index. As a result the actual plan
 executed is not the one specified by the SQL_BIG_RESULT
 hint. Similarly, there is no such test when executing
 EXPLAIN, resulting in incorrect output.
 The patch corrects the problem by testing for
 SQL_BIG_RESULT both during the explain and execution
 phases.


mysql-test/r/bdb.result:
  Bug #22781: SQL_BIG_RESULT fails to influence sort plan
   - updated sql_big_result testcase
mysql-test/r/group_by.result:
  Bug #22781: SQL_BIG_RESULT fails to influence sort plan
   - test case with MyISAM
mysql-test/r/innodb.result:
  Bug #22781: SQL_BIG_RESULT fails to influence sort plan
   - updated sql_big_result testcase
mysql-test/r/innodb_mysql.result:
  Bug #22781: SQL_BIG_RESULT fails to influence sort plan
   - test case with InnoDB
mysql-test/r/myisam.result:
  Bug #22781: SQL_BIG_RESULT fails to influence sort plan
   - updated sql_big_result testcase
mysql-test/t/group_by.test:
  Bug #22781: SQL_BIG_RESULT fails to influence sort plan
   - test case with MyISAM
mysql-test/t/innodb_mysql.test:
  Bug #22781: SQL_BIG_RESULT fails to influence sort plan
   - test case with InnoDB
sql/sql_select.cc:
  Bug #22781: SQL_BIG_RESULT fails to influence sort plan
   - When SQL_BIG_RESULT is specified, disable the optimization performed
  at execution/explain time that decides to use an index instead
  of filesort.
This commit is contained in:
unknown
2006-10-09 19:51:41 +04:00
parent 04bf9cc7c6
commit 45cad70ff4
8 changed files with 183 additions and 57 deletions
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16
mysql-test/r/innodb_mysql.result
View File

@ -337,3 +337,19 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 index NULL fkey 5 NULL 5 Using index
1 SIMPLE t1 eq_ref PRIMARY PRIMARY 4 test.t2.fkey 1 Using where
DROP TABLE t1,t2;
CREATE TABLE t1 (a INT PRIMARY KEY, b INT, c FLOAT, KEY b(b)) ENGINE = INNODB;
INSERT INTO t1 VALUES ( 1 , 1 , 1);
INSERT INTO t1 SELECT a + 1 , MOD(a + 1 , 20), 1 FROM t1;
INSERT INTO t1 SELECT a + 2 , MOD(a + 2 , 20), 1 FROM t1;
INSERT INTO t1 SELECT a + 4 , MOD(a + 4 , 20), 1 FROM t1;
INSERT INTO t1 SELECT a + 8 , MOD(a + 8 , 20), 1 FROM t1;
INSERT INTO t1 SELECT a + 16, MOD(a + 16, 20), 1 FROM t1;
INSERT INTO t1 SELECT a + 32, MOD(a + 32, 20), 1 FROM t1;
INSERT INTO t1 SELECT a + 64, MOD(a + 64, 20), 1 FROM t1;
EXPLAIN SELECT b, SUM(c) FROM t1 GROUP BY b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL b 5 NULL 128
EXPLAIN SELECT SQL_BIG_RESULT b, SUM(c) FROM t1 GROUP BY b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 128 Using filesort
DROP TABLE t1;