Bug #39844: Query Crash Mysql Server 5.0.67

Server crashed during a sort order optimization
of a dependent subquery:

SELECT
    (SELECT t1.a FROM t1, t2
      WHERE t1.a = t2.b AND t2.a = t3.c
      ORDER BY t1.a)
  FROM t3;


Bitmap of tables, that the reference to outer table
column uses, in addition to the regular table bit
has the OUTER_REF_TABLE_BIT bit set.
The only_eq_ref_tables function traverses this map
bit by bit simultaneously with join->map2table list.
Obviously join->map2table never contains an entry
for the OUTER_REF_TABLE_BIT pseudo-table, so the
server crashed there.


The only_eq_ref_tables function has been modified
to traverse regular table bits only like the
update_depend_map function (resetting of the
OUTER_REF_TABLE_BIT there is enough, but
resetting of the whole set of PSEUDO_TABLE_BITS
is used there for sure).

mysql-test/r/order_by.result

@@ -1076,3 +1076,19 @@ set session max_sort_length= 2180;
 select * from t1 order by b;
 ERROR HY001: Out of sort memory; increase server sort buffer size
 drop table t1;
+#
+# Bug #39844: Query Crash Mysql Server 5.0.67
+#
+CREATE TABLE t1 (a INT PRIMARY KEY);
+CREATE TABLE t2 (a INT PRIMARY KEY, b INT);
+CREATE TABLE t3 (c INT);
+INSERT INTO t1 (a) VALUES (1), (2);
+INSERT INTO t2 (a,b) VALUES (1,2), (2,3);
+INSERT INTO t3 (c) VALUES (1), (2);
+SELECT
+(SELECT t1.a FROM t1, t2 WHERE t1.a = t2.b AND t2.a = t3.c ORDER BY t1.a)
+FROM t3;
+(SELECT t1.a FROM t1, t2 WHERE t1.a = t2.b AND t2.a = t3.c ORDER BY t1.a)
+2
+NULL
+DROP TABLE t1, t2, t3;

mysql-test/t/order_by.test

@@ -738,3 +738,21 @@ set session max_sort_length= 2180;
 select * from t1 order by b;
 drop table t1;
 
+
+--echo #
+--echo # Bug #39844: Query Crash Mysql Server 5.0.67
+--echo #
+
+CREATE TABLE t1 (a INT PRIMARY KEY);
+CREATE TABLE t2 (a INT PRIMARY KEY, b INT);
+CREATE TABLE t3 (c INT);
+
+INSERT INTO t1 (a) VALUES (1), (2);
+INSERT INTO t2 (a,b) VALUES (1,2), (2,3);
+INSERT INTO t3 (c) VALUES (1), (2);
+
+SELECT
+  (SELECT t1.a FROM t1, t2 WHERE t1.a = t2.b AND t2.a = t3.c ORDER BY t1.a)
+  FROM t3;
+
+DROP TABLE t1, t2, t3;

sql/sql_select.cc

@@ -6574,6 +6574,7 @@ only_eq_ref_tables(JOIN *join,ORDER *order,table_map tables)
 {
   if (specialflag &  SPECIAL_SAFE_MODE)
     return 0;			// skip this optimize /* purecov: inspected */
+  tables&= ~PSEUDO_TABLE_BITS;
   for (JOIN_TAB **tab=join->map2table ; tables ; tab++, tables>>=1)
   {
     if (tables & 1 && !eq_ref_table(join, order, *tab))