Bug #20229614 : OR CONDITIONS ON MULTI-COLUMN INDEX MAY NOT

                USE ALL INDEX COLUMNS TO FILTER ROWS

ISSUE:
------
While optimizing a range scan for the OR-operator, key_or
incorrectly assumes an out-of-memory situation. This in turn
results in an incomplete condition being considered for the
query plan and gives an incorrect row estimate. Hence the
over-estimation of the number of qualifying rows.


SOLUTION:
---------
In key_or(), a key condition is cloned if it's already in
use in some other condition. In this case NULL should be
returned only if allocation fails.

The check of key_count > 0 was originally added as part of
Bug #4157. This was done to check the key_count after the
swap of keys. Here changing the "||" to "&&" ensures that
when the new key_count is greater than 0, there will be
an attempt to clone the tree.

Author: Sreeharsha Ramanavarapu

mysql-test/include/range.inc

@@ -1796,3 +1796,24 @@ eval $query_ba;
 --echo
 DROP TABLE t1,t2;
 
+--echo #Bug #20229614: OR CONDITIONS ON MULTI-COLUMN INDEX
+--echo #               MAY NOT USE ALL INDEX COLUMNS TO
+--echo #               FILTER ROWS
+
+CREATE TABLE t1 (c1 INT, c2 INT, c3 INT,
+                 PRIMARY KEY(c1, c2, c3)) ENGINE=INNODB;
+
+INSERT INTO t1 VALUES (1, 1, 1), (1, 1, 2), (1, 1, 3),
+                      (1, 1, 4), (1, 1, 5);
+INSERT INTO t1 SELECT c1, 2, c3 FROM t1;
+INSERT INTO t1 SELECT c1, 3, c3 FROM t1 WHERE c2 = 1;
+
+SELECT COUNT(*) FROM t1;
+
+# Rows considered should be 3.
+EXPLAIN SELECT c1, c2, c3
+        FROM t1
+        WHERE (c1 = 1 AND c2 = 1 AND c3 = 1) OR
+              (c1 = 1 AND c2 = 2 AND c3 = 2) OR
+              (c1 = 1 AND c2 = 2 AND c3 = 3);
+DROP TABLE t1;

mysql-test/r/range_all.result

@@ -2457,4 +2457,24 @@ a	b
 2001-01-01 11:22:33	2001-01-01 11:22:33
 
 DROP TABLE t1,t2;
+#Bug #20229614: OR CONDITIONS ON MULTI-COLUMN INDEX
+#               MAY NOT USE ALL INDEX COLUMNS TO
+#               FILTER ROWS
+CREATE TABLE t1 (c1 INT, c2 INT, c3 INT,
+PRIMARY KEY(c1, c2, c3)) ENGINE=INNODB;
+INSERT INTO t1 VALUES (1, 1, 1), (1, 1, 2), (1, 1, 3),
+(1, 1, 4), (1, 1, 5);
+INSERT INTO t1 SELECT c1, 2, c3 FROM t1;
+INSERT INTO t1 SELECT c1, 3, c3 FROM t1 WHERE c2 = 1;
+SELECT COUNT(*) FROM t1;
+COUNT(*)
+15
+EXPLAIN SELECT c1, c2, c3
+FROM t1
+WHERE (c1 = 1 AND c2 = 1 AND c3 = 1) OR
+(c1 = 1 AND c2 = 2 AND c3 = 2) OR
+(c1 = 1 AND c2 = 2 AND c3 = 3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	range	PRIMARY	PRIMARY	12	NULL	3	Using where; Using index
+DROP TABLE t1;
 set optimizer_switch=default;

mysql-test/r/range_icp.result

@@ -2457,4 +2457,24 @@ a	b
 2001-01-01 11:22:33	2001-01-01 11:22:33
 
 DROP TABLE t1,t2;
+#Bug #20229614: OR CONDITIONS ON MULTI-COLUMN INDEX
+#               MAY NOT USE ALL INDEX COLUMNS TO
+#               FILTER ROWS
+CREATE TABLE t1 (c1 INT, c2 INT, c3 INT,
+PRIMARY KEY(c1, c2, c3)) ENGINE=INNODB;
+INSERT INTO t1 VALUES (1, 1, 1), (1, 1, 2), (1, 1, 3),
+(1, 1, 4), (1, 1, 5);
+INSERT INTO t1 SELECT c1, 2, c3 FROM t1;
+INSERT INTO t1 SELECT c1, 3, c3 FROM t1 WHERE c2 = 1;
+SELECT COUNT(*) FROM t1;
+COUNT(*)
+15
+EXPLAIN SELECT c1, c2, c3
+FROM t1
+WHERE (c1 = 1 AND c2 = 1 AND c3 = 1) OR
+(c1 = 1 AND c2 = 2 AND c3 = 2) OR
+(c1 = 1 AND c2 = 2 AND c3 = 3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	range	PRIMARY	PRIMARY	12	NULL	3	Using where; Using index
+DROP TABLE t1;
 set optimizer_switch=default;

mysql-test/r/range_icp_mrr.result

@@ -2457,4 +2457,24 @@ a	b
 2001-01-01 11:22:33	2001-01-01 11:22:33
 
 DROP TABLE t1,t2;
+#Bug #20229614: OR CONDITIONS ON MULTI-COLUMN INDEX
+#               MAY NOT USE ALL INDEX COLUMNS TO
+#               FILTER ROWS
+CREATE TABLE t1 (c1 INT, c2 INT, c3 INT,
+PRIMARY KEY(c1, c2, c3)) ENGINE=INNODB;
+INSERT INTO t1 VALUES (1, 1, 1), (1, 1, 2), (1, 1, 3),
+(1, 1, 4), (1, 1, 5);
+INSERT INTO t1 SELECT c1, 2, c3 FROM t1;
+INSERT INTO t1 SELECT c1, 3, c3 FROM t1 WHERE c2 = 1;
+SELECT COUNT(*) FROM t1;
+COUNT(*)
+15
+EXPLAIN SELECT c1, c2, c3
+FROM t1
+WHERE (c1 = 1 AND c2 = 1 AND c3 = 1) OR
+(c1 = 1 AND c2 = 2 AND c3 = 2) OR
+(c1 = 1 AND c2 = 2 AND c3 = 3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	range	PRIMARY	PRIMARY	12	NULL	3	Using where; Using index
+DROP TABLE t1;
 set optimizer_switch=default;

mysql-test/r/range_mrr.result

@@ -2457,4 +2457,24 @@ a	b
 2001-01-01 11:22:33	2001-01-01 11:22:33
 
 DROP TABLE t1,t2;
+#Bug #20229614: OR CONDITIONS ON MULTI-COLUMN INDEX
+#               MAY NOT USE ALL INDEX COLUMNS TO
+#               FILTER ROWS
+CREATE TABLE t1 (c1 INT, c2 INT, c3 INT,
+PRIMARY KEY(c1, c2, c3)) ENGINE=INNODB;
+INSERT INTO t1 VALUES (1, 1, 1), (1, 1, 2), (1, 1, 3),
+(1, 1, 4), (1, 1, 5);
+INSERT INTO t1 SELECT c1, 2, c3 FROM t1;
+INSERT INTO t1 SELECT c1, 3, c3 FROM t1 WHERE c2 = 1;
+SELECT COUNT(*) FROM t1;
+COUNT(*)
+15
+EXPLAIN SELECT c1, c2, c3
+FROM t1
+WHERE (c1 = 1 AND c2 = 1 AND c3 = 1) OR
+(c1 = 1 AND c2 = 2 AND c3 = 2) OR
+(c1 = 1 AND c2 = 2 AND c3 = 3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	range	PRIMARY	PRIMARY	12	NULL	3	Using where; Using index
+DROP TABLE t1;
 set optimizer_switch=default;

mysql-test/r/range_mrr_cost.result

@@ -2457,4 +2457,24 @@ a	b
 2001-01-01 11:22:33	2001-01-01 11:22:33
 
 DROP TABLE t1,t2;
+#Bug #20229614: OR CONDITIONS ON MULTI-COLUMN INDEX
+#               MAY NOT USE ALL INDEX COLUMNS TO
+#               FILTER ROWS
+CREATE TABLE t1 (c1 INT, c2 INT, c3 INT,
+PRIMARY KEY(c1, c2, c3)) ENGINE=INNODB;
+INSERT INTO t1 VALUES (1, 1, 1), (1, 1, 2), (1, 1, 3),
+(1, 1, 4), (1, 1, 5);
+INSERT INTO t1 SELECT c1, 2, c3 FROM t1;
+INSERT INTO t1 SELECT c1, 3, c3 FROM t1 WHERE c2 = 1;
+SELECT COUNT(*) FROM t1;
+COUNT(*)
+15
+EXPLAIN SELECT c1, c2, c3
+FROM t1
+WHERE (c1 = 1 AND c2 = 1 AND c3 = 1) OR
+(c1 = 1 AND c2 = 2 AND c3 = 2) OR
+(c1 = 1 AND c2 = 2 AND c3 = 3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	range	PRIMARY	PRIMARY	12	NULL	3	Using where; Using index
+DROP TABLE t1;
 set optimizer_switch=default;

mysql-test/r/range_none.result

@@ -2456,4 +2456,24 @@ a	b
 2001-01-01 11:22:33	2001-01-01 11:22:33
 
 DROP TABLE t1,t2;
+#Bug #20229614: OR CONDITIONS ON MULTI-COLUMN INDEX
+#               MAY NOT USE ALL INDEX COLUMNS TO
+#               FILTER ROWS
+CREATE TABLE t1 (c1 INT, c2 INT, c3 INT,
+PRIMARY KEY(c1, c2, c3)) ENGINE=INNODB;
+INSERT INTO t1 VALUES (1, 1, 1), (1, 1, 2), (1, 1, 3),
+(1, 1, 4), (1, 1, 5);
+INSERT INTO t1 SELECT c1, 2, c3 FROM t1;
+INSERT INTO t1 SELECT c1, 3, c3 FROM t1 WHERE c2 = 1;
+SELECT COUNT(*) FROM t1;
+COUNT(*)
+15
+EXPLAIN SELECT c1, c2, c3
+FROM t1
+WHERE (c1 = 1 AND c2 = 1 AND c3 = 1) OR
+(c1 = 1 AND c2 = 2 AND c3 = 2) OR
+(c1 = 1 AND c2 = 2 AND c3 = 3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	range	PRIMARY	PRIMARY	12	NULL	3	Using where; Using index
+DROP TABLE t1;
 set optimizer_switch=default;

sql/opt_range.cc

@@ -7804,7 +7804,7 @@ key_or(RANGE_OPT_PARAM *param, SEL_ARG *key1, SEL_ARG *key2)
     {
       swap_variables(SEL_ARG *,key1,key2);
     }
-    if (key1->use_count > 0 || !(key1=key1->clone_tree(param)))
+    if (key1->use_count > 0 && (key1= key1->clone_tree(param)) == NULL)
       return 0;                                 // OOM
   }