Bug#45266: Uninitialized variable lead to an empty result.

The TABLE::reginfo.impossible_range is used by the optimizer to indicate
that the condition applied to the table is impossible. It wasn't initialized
at table opening and this might lead to an empty result on complex queries:
a query might set the impossible_range flag on a table and when the query finishes,
all tables are returned back to the table cache. The next query that uses the table
with the impossible_range flag set and an index over the table will see the flag
and thus return an empty result.

The open_table function now initializes the TABLE::reginfo.impossible_range
variable.

mysql-test/r/select.result:
  A test case for the bug#45266: Uninitialized variable lead to an empty result.
mysql-test/t/select.test:
  A test case for the bug#45266: Uninitialized variable lead to an empty result.
sql/sql_base.cc:
  Bug#45266: Uninitialized variable lead to an empty result.
  The open_table function now initializes the TABLE::reginfo.impossible_range
  variable.
sql/sql_select.cc:
  Bug#45266: Uninitialized variable lead to an empty result.
  The open_table function now initializes the TABLE::reginfo.impossible_range
  variable.
sql/structs.h:
  Bug#45266: Uninitialized variable lead to an empty result.
  A comment is added.

1 files changed, 86 insertions, 0 deletions

diff --git a/mysql-test/t/select.test b/mysql-test/t/select.test
index 715bdf0e667..7d3785ecccc 100644
--- a/mysql-test/t/select.test
+++ b/mysql-test/t/select.test
@@ -3799,4 +3799,90 @@ EXPLAIN EXTENDED SELECT * FROM t1 WHERE (a=a AND a=a AND b=b) OR b > 20;
 EXPLAIN EXTENDED SELECT * FROM t1 WHERE (a=a AND b=b AND a=a) OR b > 20;
 DROP TABLE t1;
 
+
+--echo #
+--echo # Bug#45266: Uninitialized variable lead to an empty result.
+--echo #
+--disable_warnings
+drop table if exists A,AA,B,BB;
+CREATE TABLE `A` (
+  `pk` int(11) NOT NULL AUTO_INCREMENT,
+  `date_key` date NOT NULL,
+  `date_nokey` date NOT NULL,
+  `datetime_key` datetime NOT NULL,
+  `int_nokey` int(11) NOT NULL,
+  `time_key` time NOT NULL,
+  `time_nokey` time NOT NULL,
+  PRIMARY KEY (`pk`),
+  KEY `date_key` (`date_key`),
+  KEY `time_key` (`time_key`),
+  KEY `datetime_key` (`datetime_key`)
+);
+
+CREATE TABLE `AA` (
+  `pk` int(11) NOT NULL AUTO_INCREMENT,
+  `int_nokey` int(11) NOT NULL,
+  `time_key` time NOT NULL,
+  KEY `time_key` (`time_key`),
+  PRIMARY KEY (`pk`)
+);
+
+CREATE TABLE `B` (
+  `date_nokey` date NOT NULL,
+  `date_key` date NOT NULL,
+  `time_key` time NOT NULL,
+  `datetime_nokey` datetime NOT NULL,
+  `varchar_key` varchar(1) NOT NULL,
+  KEY `date_key` (`date_key`),
+  KEY `time_key` (`time_key`),
+  KEY `varchar_key` (`varchar_key`)
+);
+
+INSERT INTO `B` VALUES ('2003-07-28','2003-07-28','15:13:38','0000-00-00 00:00:00','f'),('0000-00-00','0000-00-00','00:05:48','2004-07-02 14:34:13','x');
+
+CREATE TABLE `BB` (
+  `pk` int(11) NOT NULL AUTO_INCREMENT,
+  `int_nokey` int(11) NOT NULL,
+  `date_key` date NOT NULL,
+  `varchar_nokey` varchar(1) NOT NULL,
+  `date_nokey` date NOT NULL,
+  PRIMARY KEY (`pk`),
+  KEY `date_key` (`date_key`)
+);
+
+INSERT INTO `BB` VALUES (10,8,'0000-00-00','i','0000-00-00'),(11,0,'2005-08-18','','2005-08-18');
+# Test #1
+SELECT table1 . `pk` AS field1 
+  FROM 
+    (BB AS table1 INNER JOIN 
+      (AA AS table2 STRAIGHT_JOIN A AS table3 
+        ON ( table3 . `date_key` = table2 . `pk` ))
+       ON ( table3 . `datetime_key` = table2 . `int_nokey` ))
+  WHERE  ( table3 . `date_key` <= 4 AND table2 . `pk` = table1 . `varchar_nokey`)
+  GROUP BY field1 ;
+
+SELECT table3 .`date_key` field1
+  FROM
+    B table1 LEFT JOIN B table3 JOIN
+      (BB table6 JOIN A table7 ON table6 .`varchar_nokey`)
+       ON table6 .`int_nokey` ON table6 .`date_key`
+  WHERE  NOT ( table1 .`varchar_key`  AND table7 .`pk`) GROUP  BY field1;
+
+# Test #2
+SELECT table4 . `time_nokey` AS field1 FROM 
+  (AA AS table1 CROSS JOIN 
+    (AA AS table2 STRAIGHT_JOIN 
+      (B AS table3 STRAIGHT_JOIN A AS table4 
+       ON ( table4 . `date_key` = table3 . `time_key` ))
+     ON ( table4 . `pk` = table3 . `date_nokey` ))
+   ON ( table4 . `time_key` = table3 . `datetime_nokey` ))
+  WHERE  ( table4 . `time_key` < table1 . `time_key` AND
+            table1 . `int_nokey` != 'f')
+  GROUP BY field1  ORDER BY field1 , field1;
+
+SELECT table1 .`time_key` field2  FROM B table1  LEFT JOIN  BB JOIN A table5 ON table5 .`date_nokey`  ON table5 .`int_nokey` GROUP  BY field2;
+--enable_warnings
+
+drop table A,AA,B,BB;
+--echo #end of test for bug#45266
 --echo End of 5.1 tests