diff options
| -rw-r--r-- | mysql-test/r/order_by.result | 21 | ||||
| -rw-r--r-- | mysql-test/t/order_by.test | 25 | ||||
| -rw-r--r-- | sql/sql_select.cc | 9 |
3 files changed, 55 insertions, 0 deletions
diff --git a/mysql-test/r/order_by.result b/mysql-test/r/order_by.result index fa5d8142baf..51c8f0cc741 100644 --- a/mysql-test/r/order_by.result +++ b/mysql-test/r/order_by.result @@ -1617,6 +1617,27 @@ id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range a a 5 NULL 2 Using where; Using temporary; Using filesort 1 SIMPLE t2 ALL NULL NULL NULL NULL 10 Using join buffer DROP TABLE t1, t2; +# +# Bug #50394: Regression in EXPLAIN with index scan, LIMIT, GROUP BY and +# ORDER BY computed col +# +CREATE TABLE t1 ( a INT NOT NULL, b INT NOT NULL, KEY( a, b ) ); +INSERT INTO t1 VALUES (1, 1), (2, 2), (3, 3), (4, 4), (5, 5); +INSERT INTO t1 SELECT a + 5, b + 5 FROM t1; +CREATE TABLE t2( a INT PRIMARY KEY, b INT ); +INSERT INTO t2 VALUES (1, 1), (2, 2), (3, 3), (4, 4), (5, 5); +INSERT INTO t2 SELECT a + 5, b + 5 FROM t2; +EXPLAIN +SELECT count(*) AS c, t1.a +FROM t1 JOIN t2 ON t1.b = t2.a +WHERE t2.b = 1 +GROUP BY t1.a +ORDER by c +LIMIT 2; +id select_type table type possible_keys key key_len ref rows Extra +1 SIMPLE t1 index NULL a 8 NULL 10 Using index; Using temporary; Using filesort +1 SIMPLE t2 eq_ref PRIMARY PRIMARY 4 test.t1.b 1 Using where +DROP TABLE t1, t2; End of 5.1 tests # # Bug #38745: MySQL 5.1 optimizer uses filesort for ORDER BY diff --git a/mysql-test/t/order_by.test b/mysql-test/t/order_by.test index 2ea169d950d..7869a01a84d 100644 --- a/mysql-test/t/order_by.test +++ b/mysql-test/t/order_by.test @@ -1467,6 +1467,31 @@ SELECT * FROM t1 FORCE INDEX FOR JOIN (a), t2 WHERE t1.a < 2 ORDER BY t1.a; DROP TABLE t1, t2; +--echo # +--echo # Bug #50394: Regression in EXPLAIN with index scan, LIMIT, GROUP BY and +--echo # ORDER BY computed col +--echo # +CREATE TABLE t1 ( a INT NOT NULL, b INT NOT NULL, KEY( a, b ) ); + +INSERT INTO t1 VALUES (1, 1), (2, 2), (3, 3), (4, 4), (5, 5); +INSERT INTO t1 SELECT a + 5, b + 5 FROM t1; + +CREATE TABLE t2( a INT PRIMARY KEY, b INT ); + +INSERT INTO t2 VALUES (1, 1), (2, 2), (3, 3), (4, 4), (5, 5); +INSERT INTO t2 SELECT a + 5, b + 5 FROM t2; + +EXPLAIN +SELECT count(*) AS c, t1.a +FROM t1 JOIN t2 ON t1.b = t2.a +WHERE t2.b = 1 +GROUP BY t1.a +ORDER by c +LIMIT 2; + +DROP TABLE t1, t2; + + --echo End of 5.1 tests diff --git a/sql/sql_select.cc b/sql/sql_select.cc index 29a78cb31dc..07e109c34ea 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -1523,6 +1523,15 @@ JOIN::optimize() if (order) { /* + Do we need a temporary table due to the ORDER BY not being equal to + the GROUP BY? The call to test_if_skip_sort_order above tests for the + GROUP BY clause only and hence is not valid in this case. So the + estimated number of rows to be read from the first table is not valid. + We clear it here so that it doesn't show up in EXPLAIN. + */ + if (need_tmp && (select_options & SELECT_DESCRIBE) != 0) + join_tab[const_tables].limit= 0; + /* Force using of tmp table if sorting by a SP or UDF function due to their expensive and probably non-deterministic nature. */ |