Fixed bug #16081: row equalities were not taken into

account by the optimizer.
Now all row equalities are converted into conjunctions of
equalities between row elements. They are taken into account
by the optimizer together with the original regular equality
predicates.


mysql-test/r/join_outer.result:
  Adjusted results after fix for bug #16081.
mysql-test/r/row.result:
  Added a test cases for bug #16081.
mysql-test/t/row.test:
  Added a test cases for bug #16081.
sql/sql_list.h:
  Corrected the copy constructor for the class base_list.
  The previous implementation resulted in creation of an
  inconsistent base_list if the source list was empty.

1 files changed, 47 insertions, 0 deletions

diff --git a/mysql-test/t/row.test b/mysql-test/t/row.test
index 6301cc0f584..63c611e6be6 100644
--- a/mysql-test/t/row.test
+++ b/mysql-test/t/row.test
@@ -92,3 +92,50 @@ SELECT ROW(NULL,10) <=> ROW(3,NULL);
 #
 SELECT ROW(1,1,1) = ROW(1,1,1) as `1`, ROW(1,1,1) = ROW(1,2,1) as `0`, ROW(1,NULL,1) = ROW(2,2,1) as `0`, ROW(1,NULL,1) = ROW(1,2,2) as `0`, ROW(1,NULL,1) = ROW(1,2,1) as `null` ;
 select row(NULL,1)=(2,0);
+
+#
+# Bug #16081: row equalities are to be used for query optimizations  
+#
+
+CREATE TABLE t1 (a int, b int, PRIMARY KEY (a,b));
+INSERT INTO t1 VALUES (1,1), (2,1), (3,1), (1,2), (3,2), (3,3);
+
+EXPLAIN SELECT * FROM t1 WHERE a=3 AND b=2;
+EXPLAIN SELECT * FROM t1 WHERE (a,b)=(3,2);
+SELECT * FROM t1 WHERE a=3 and b=2;
+SELECT * FROM t1 WHERE (a,b)=(3,2);
+
+CREATE TABLE t2 (a int, b int, c int, PRIMARY KEY (a,b,c));
+INSERT INTO t2 VALUES
+  (1,1,2), (3,1,3), (1,2,2), (4,4,2),
+  (1,1,1), (3,1,1), (1,2,1);
+
+EXPLAIN SELECT * FROM t1,t2 WHERE t1.a=t2.a AND t1.b=t2.b;
+EXPLAIN SELECT * FROM t1,t2 WHERE (t1.a,t1.b)=(t2.a,t2.b);
+SELECT * FROM t1,t2 WHERE t1.a=t2.a and t1.b=t2.b;
+SELECT * FROM t1,t2 WHERE (t1.a,t1.b)=(t2.a,t2.b);
+
+EXPLAIN SELECT * FROM t1,t2 WHERE t1.a=t2.a AND t1.b=2;
+EXPLAIN SELECT * FROM t1,t2 WHERE (t1.a,t1.b)=(t2.a,2);
+SELECT * FROM t1,t2 WHERE t1.a=1 and t1.b=t2.b;
+SELECT * FROM t1,t2 WHERE (t1.a,t1.b)=(t2.a,2);
+
+EXPLAIN EXTENDED SELECT * FROM t1,t2 WHERE (t1.a,t1.b)=(t2.a,t2.b+1);
+SELECT * FROM t1,t2 WHERE (t1.a,t1.b)=(t2.a,t2.b+1);
+
+EXPLAIN EXTENDED SELECT * FROM t1,t2 WHERE (t1.a-1,t1.b)=(t2.a-1,t2.b+1);
+SELECT * FROM t1,t2 WHERE (t1.a-1,t1.b)=(t2.a-1,t2.b+1);
+
+EXPLAIN SELECT * FROM t2 WHERE a=3 AND b=2;
+EXPLAIN SELECT * FROM t2 WHERE (a,b)=(3,2);
+SELECT * FROM t2 WHERE a=3 and b=2;
+SELECT * FROM t2 WHERE (a,b)=(3,2);
+
+EXPLAIN SELECT * FROM t1,t2 WHERE t2.a=t1.a AND t2.b=2 AND t2.c=1;
+EXPLAIN EXTENDED SELECT * FROM t1,t2 WHERE (t2.a,(t2.b,t2.c))=(t1.a,(2,1));
+SELECT * FROM t1,t2 WHERE (t2.a,(t2.b,t2.c))=(t1.a,(2,1));
+
+EXPLAIN EXTENDED SELECT * FROM t1,t2 WHERE t2.a=t1.a AND (t2.b,t2.c)=(2,1);
+SELECT * FROM t1,t2 WHERE t2.a=t1.a AND (t2.b,t2.c)=(2,1);
+
+DROP TABLE t1,t2;