MDEV-12721 Wrong execution plan for WHERE (date_field <=> timestamp_expr AND TRUE)

mysql-test/r/type_date.result

@@ -429,17 +429,26 @@ select @a;
 #
 # BUG LP:1008487 virtual bool Item_cache::is_expensive(): Assertion `example' failed
 #
+SET TIMESTAMP=UNIX_TIMESTAMP('2017-01-03 00:00:00');
 create table t1(a date,key(a));
 insert into t1 values ('2012-01-01'),('2012-02-02');
 explain
 select 1 from t1 as t1_0 inner join t1 as t2 on (t1_0.a <=> now()) join t1 on 1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1_0	ref	a	a	4	const	0	Using where; Using index
+1	SIMPLE	t1_0	ref	a	a	4	const	1	Using where; Using index
 1	SIMPLE	t2	index	NULL	a	4	NULL	2	Using index; Using join buffer (flat, BNL join)
 1	SIMPLE	t1	index	NULL	a	4	NULL	2	Using index; Using join buffer (incremental, BNL join)
 select 1 from t1 as t1_0 inner join t1 as t2 on (t1_0.a <=> now()) join t1 on 1;
 1
+SET TIMESTAMP=UNIX_TIMESTAMP('2012-01-03 00:00:01');
+explain
+select 1 from t1 as t1_0 inner join t1 as t2 on (t1_0.a <=> now()) join t1 on 1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+select 1 from t1 as t1_0 inner join t1 as t2 on (t1_0.a <=> now()) join t1 on 1;
+1
 drop table t1;
+SET TIMESTAMP=DEFAULT;
 #
 # MDEV-9521 Least function returns 0000-00-00 for null date columns instead of null
 # MDEV-9972 Least function retuns date in date time format
@@ -845,3 +854,27 @@ DROP TABLE t1;
 #
 # End of 10.1 tests
 #
+#
+# Start of 10.3 tests
+#
+#
+# MDEV-12721 Wrong execution plan for WHERE (date_field <=> timestamp_expr AND TRUE)
+#
+CREATE TABLE t1(a DATE,KEY(a));
+INSERT INTO t1 VALUES ('2012-01-01'),('2012-02-02');
+EXPLAIN SELECT 1 FROM t1 WHERE t1.a <=> TIMESTAMP'2001-01-01 00:00:01' AND TRUE;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+EXPLAIN SELECT 1 FROM t1 WHERE t1.a <=> TIMESTAMP('2001-01-01', '00:00:01') AND TRUE;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+EXPLAIN SELECT 1 FROM t1 WHERE t1.a <=> TIMESTAMP'2001-01-01 00:00:00' AND TRUE;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ref	a	a	4	const	1	Using where; Using index
+EXPLAIN SELECT 1 FROM t1 WHERE t1.a <=> TIMESTAMP('2001-01-01', '00:00:00') AND TRUE;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ref	a	a	4	const	1	Using where; Using index
+DROP TABLE t1;
+#
+# End of 10.3 tests
+#

mysql-test/t/type_date.test

@@ -369,12 +369,18 @@ select @a;
 --echo #
 --echo # BUG LP:1008487 virtual bool Item_cache::is_expensive(): Assertion `example' failed
 --echo #
+SET TIMESTAMP=UNIX_TIMESTAMP('2017-01-03 00:00:00');
 create table t1(a date,key(a));
 insert into t1 values ('2012-01-01'),('2012-02-02');
 explain
 select 1 from t1 as t1_0 inner join t1 as t2 on (t1_0.a <=> now()) join t1 on 1;
 select 1 from t1 as t1_0 inner join t1 as t2 on (t1_0.a <=> now()) join t1 on 1;
+SET TIMESTAMP=UNIX_TIMESTAMP('2012-01-03 00:00:01');
+explain
+select 1 from t1 as t1_0 inner join t1 as t2 on (t1_0.a <=> now()) join t1 on 1;
+select 1 from t1 as t1_0 inner join t1 as t2 on (t1_0.a <=> now()) join t1 on 1;
 drop table t1;
+SET TIMESTAMP=DEFAULT;
 
 --echo #
 --echo # MDEV-9521 Least function returns 0000-00-00 for null date columns instead of null
@@ -580,3 +586,22 @@ DROP TABLE t1;
 --echo #
 --echo # End of 10.1 tests
 --echo #
+
+--echo #
+--echo # Start of 10.3 tests
+--echo #
+
+--echo #
+--echo # MDEV-12721 Wrong execution plan for WHERE (date_field <=> timestamp_expr AND TRUE)
+--echo #
+CREATE TABLE t1(a DATE,KEY(a));
+INSERT INTO t1 VALUES ('2012-01-01'),('2012-02-02');
+EXPLAIN SELECT 1 FROM t1 WHERE t1.a <=> TIMESTAMP'2001-01-01 00:00:01' AND TRUE;
+EXPLAIN SELECT 1 FROM t1 WHERE t1.a <=> TIMESTAMP('2001-01-01', '00:00:01') AND TRUE;
+EXPLAIN SELECT 1 FROM t1 WHERE t1.a <=> TIMESTAMP'2001-01-01 00:00:00' AND TRUE;
+EXPLAIN SELECT 1 FROM t1 WHERE t1.a <=> TIMESTAMP('2001-01-01', '00:00:00') AND TRUE;
+DROP TABLE t1;
+
+--echo #
+--echo # End of 10.3 tests
+--echo #

sql/opt_range.cc

@@ -8030,33 +8030,53 @@ Item_bool_func::get_mm_leaf(RANGE_OPT_PARAM *param,
         field->type_handler() == &type_handler_set)
     {
       if (type == EQ_FUNC || type == EQUAL_FUNC)
-      {
-        tree= new (alloc) SEL_ARG(field, 0, 0);
-        tree->type= SEL_ARG::IMPOSSIBLE;
-      }
+        tree= new (alloc) SEL_ARG_IMPOSSIBLE(field);
       goto end;
     }
 
     if (err == 2 && field->cmp_type() == STRING_RESULT)
     {
       if (type == EQ_FUNC || type == EQUAL_FUNC)
-      {
-        tree= new (alloc) SEL_ARG(field, 0, 0);
-        tree->type= SEL_ARG::IMPOSSIBLE;
-      }
+        tree= new (alloc) SEL_ARG_IMPOSSIBLE(field);
       else
         tree= NULL; /*  Cannot infer anything */
       goto end;
     }
 
-    if (field->cmp_type() != value->result_type())
+    if (err == 3 && field->type() == FIELD_TYPE_DATE)
+    {
+      /*
+        We were saving DATETIME into a DATE column, the conversion went ok
+        but a non-zero time part was cut off.
+
+        In MySQL's SQL dialect, DATE and DATETIME are compared as datetime
+        values. Index over a DATE column uses DATE comparison. Changing
+        from one comparison to the other is possible:
+
+        datetime(date_col)< '2007-12-10 12:34:55' -> date_col<='2007-12-10'
+        datetime(date_col)<='2007-12-10 12:34:55' -> date_col<='2007-12-10'
+
+        datetime(date_col)> '2007-12-10 12:34:55' -> date_col>='2007-12-10'
+        datetime(date_col)>='2007-12-10 12:34:55' -> date_col>='2007-12-10'
+
+        but we'll need to convert '>' to '>=' and '<' to '<='. This will
+        be done together with other types at the end of this function
+        (grep for stored_field_cmp_to_item)
+      */
+      if (type == EQ_FUNC || type == EQUAL_FUNC)
+      {
+        tree= new (alloc) SEL_ARG_IMPOSSIBLE(field);
+        goto end;
+      }
+      // Continue with processing non-equality ranges
+    }
+    else if (field->cmp_type() != value->result_type())
     {
       if ((type == EQ_FUNC || type == EQUAL_FUNC) &&
           value->result_type() == item_cmp_type(field->result_type(),
                                                 value->result_type()))
       {
-        tree= new (alloc) SEL_ARG(field, 0, 0);
-        tree->type= SEL_ARG::IMPOSSIBLE;
+        tree= new (alloc) SEL_ARG_IMPOSSIBLE(field);
         goto end;
       }
       else
@@ -8066,31 +8086,7 @@ Item_bool_func::get_mm_leaf(RANGE_OPT_PARAM *param,
           for the cases like int_field > 999999999999999999999999 as well.
         */
         tree= 0;
-        if (err == 3 && field->type() == FIELD_TYPE_DATE &&
-            (type == GT_FUNC || type == GE_FUNC ||
-             type == LT_FUNC || type == LE_FUNC) )
-        {
-          /*
-            We were saving DATETIME into a DATE column, the conversion went ok
-            but a non-zero time part was cut off.
-
-            In MySQL's SQL dialect, DATE and DATETIME are compared as datetime
-            values. Index over a DATE column uses DATE comparison. Changing 
-            from one comparison to the other is possible:
-
-            datetime(date_col)< '2007-12-10 12:34:55' -> date_col<='2007-12-10'
-            datetime(date_col)<='2007-12-10 12:34:55' -> date_col<='2007-12-10'
-
-            datetime(date_col)> '2007-12-10 12:34:55' -> date_col>='2007-12-10'
-            datetime(date_col)>='2007-12-10 12:34:55' -> date_col>='2007-12-10'
-
-            but we'll need to convert '>' to '>=' and '<' to '<='. This will
-            be done together with other types at the end of this function
-            (grep for stored_field_cmp_to_item)
-          */
-        }
-        else
-          goto end;
+        goto end;
       }
     }
 

sql/opt_range.h

@@ -594,6 +594,17 @@ class SEL_ARG :public Sql_alloc
 };
 
 
+class SEL_ARG_IMPOSSIBLE: public SEL_ARG
+{
+public:
+  SEL_ARG_IMPOSSIBLE(Field *field)
+   :SEL_ARG(field, 0, 0)
+  {
+    type= SEL_ARG::IMPOSSIBLE;
+  }
+};
+
+
 class RANGE_OPT_PARAM
 {
 public: