MDEV-746: Merged mysql fix of the bug LP:1002546 & MySQL Bug#13651009.

Empty result after reading const tables now works for subqueries.

mysql-test/r/subselect.result

@@ -5294,4 +5294,115 @@ WHERE (col_varchar_nokey, 'x') IN
 col_int_nokey
 1
 DROP TABLE ot,it1,it2;
+#
+# MDEV-746
+# Bug#13651009 WRONG RESULT FROM DERIVED TABLE IF THE SUBQUERY
+# HAS AN EMPTY RESULT
+#
+CREATE TABLE t1 (
+pk int NOT NULL,
+col_int_nokey int NOT NULL,
+col_int_key int NOT NULL,
+col_time_key time NOT NULL,
+col_varchar_key varchar(1) NOT NULL,
+col_varchar_nokey varchar(1) NOT NULL,
+PRIMARY KEY (pk),
+KEY col_int_key (col_int_key),
+KEY col_time_key (col_time_key),
+KEY col_varchar_key (col_varchar_key,col_int_key)
+) ENGINE=MyISAM;
+CREATE TABLE t2 (
+pk int NOT NULL AUTO_INCREMENT,
+col_int_nokey int NOT NULL,
+col_int_key int NOT NULL,
+col_time_key time NOT NULL,
+col_varchar_key varchar(1) NOT NULL,
+col_varchar_nokey varchar(1) NOT NULL,
+PRIMARY KEY (pk),
+KEY col_int_key (col_int_key),
+KEY col_time_key (col_time_key),
+KEY col_varchar_key (col_varchar_key,col_int_key)
+) ENGINE=MyISAM;
+INSERT INTO t2 VALUES (1,4,4,'00:00:00','b','b');
+SET @var2:=4, @var3:=8;
+
+Testcase without inner subquery
+EXPLAIN SELECT @var3:=12, sq4_alias1.*
+FROM t1 AS sq4_alias1
+WHERE (sq4_alias1.col_varchar_key + NULL) IS NULL OR
+sq4_alias1.col_varchar_key = @var3;
+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 @var3:=12, sq4_alias1.*
+FROM t1 AS sq4_alias1
+WHERE (sq4_alias1.col_varchar_key + NULL) IS NULL OR
+sq4_alias1.col_varchar_key = @var3;
+@var3:=12	pk	col_int_nokey	col_int_key	col_time_key	col_varchar_key	col_varchar_nokey
+SELECT @var3;
+@var3
+8
+EXPLAIN SELECT * FROM ( SELECT @var3:=12, sq4_alias1.*
+FROM t1 AS sq4_alias1
+WHERE (sq4_alias1.col_varchar_key + NULL) IS NULL OR
+sq4_alias1.col_varchar_key = @var3 ) AS alias3;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	<derived2>	system	NULL	NULL	NULL	NULL	0	const row not found
+2	DERIVED	NULL	NULL	NULL	NULL	NULL	NULL	NULL	no matching row in const table
+SELECT * FROM ( SELECT @var3:=12, sq4_alias1.*
+FROM t1 AS sq4_alias1
+WHERE (sq4_alias1.col_varchar_key + NULL) IS NULL OR
+sq4_alias1.col_varchar_key = @var3 ) AS alias3;
+@var3:=12	pk	col_int_nokey	col_int_key	col_time_key	col_varchar_key	col_varchar_nokey
+SELECT @var3;
+@var3
+8
+
+Testcase with inner subquery; crashed WL#6095
+SET @var3=8;
+EXPLAIN SELECT sq4_alias1.*
+FROM t1 AS sq4_alias1
+WHERE (sq4_alias1.col_varchar_key , sq4_alias1.col_varchar_nokey)
+NOT IN
+(SELECT c_sq1_alias1.col_varchar_key AS c_sq1_field1,
+c_sq1_alias1.col_varchar_nokey AS c_sq1_field2
+FROM t2 AS c_sq1_alias1
+WHERE (c_sq1_alias1.col_int_nokey != @var2
+OR c_sq1_alias1.pk != @var3));
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+2	DEPENDENT SUBQUERY	c_sq1_alias1	system	PRIMARY,col_varchar_key	NULL	NULL	NULL	1	
+SELECT sq4_alias1.*
+FROM t1 AS sq4_alias1
+WHERE (sq4_alias1.col_varchar_key , sq4_alias1.col_varchar_nokey)
+NOT IN
+(SELECT c_sq1_alias1.col_varchar_key AS c_sq1_field1,
+c_sq1_alias1.col_varchar_nokey AS c_sq1_field2
+FROM t2 AS c_sq1_alias1
+WHERE (c_sq1_alias1.col_int_nokey != @var2
+OR c_sq1_alias1.pk != @var3));
+pk	col_int_nokey	col_int_key	col_time_key	col_varchar_key	col_varchar_nokey
+EXPLAIN SELECT * FROM ( SELECT sq4_alias1.*
+FROM t1 AS sq4_alias1
+WHERE (sq4_alias1.col_varchar_key , sq4_alias1.col_varchar_nokey)
+NOT IN
+(SELECT c_sq1_alias1.col_varchar_key AS c_sq1_field1,
+c_sq1_alias1.col_varchar_nokey AS c_sq1_field2
+FROM t2 AS c_sq1_alias1
+WHERE (c_sq1_alias1.col_int_nokey != @var2
+OR c_sq1_alias1.pk != @var3)) ) AS alias3;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	<derived2>	system	NULL	NULL	NULL	NULL	0	const row not found
+2	DERIVED	NULL	NULL	NULL	NULL	NULL	NULL	NULL	no matching row in const table
+3	DEPENDENT SUBQUERY	c_sq1_alias1	system	PRIMARY,col_varchar_key	NULL	NULL	NULL	1	
+SELECT * FROM ( SELECT sq4_alias1.*
+FROM t1 AS sq4_alias1
+WHERE (sq4_alias1.col_varchar_key , sq4_alias1.col_varchar_nokey)
+NOT IN
+(SELECT c_sq1_alias1.col_varchar_key AS c_sq1_field1,
+c_sq1_alias1.col_varchar_nokey AS c_sq1_field2
+FROM t2 AS c_sq1_alias1
+WHERE (c_sq1_alias1.col_int_nokey != @var2
+OR c_sq1_alias1.pk != @var3)) ) AS alias3;
+pk	col_int_nokey	col_int_key	col_time_key	col_varchar_key	col_varchar_nokey
+DROP TABLE t1,t2;
 End of 5.2 tests

mysql-test/t/subselect.test

@@ -4144,4 +4144,81 @@ SELECT col_int_nokey FROM ot
 
 DROP TABLE ot,it1,it2;
 
+--echo #
+--echo # MDEV-746
+--echo # Bug#13651009 WRONG RESULT FROM DERIVED TABLE IF THE SUBQUERY
+--echo # HAS AN EMPTY RESULT
+--echo #
+
+CREATE TABLE t1 (
+  pk int NOT NULL,
+  col_int_nokey int NOT NULL,
+  col_int_key int NOT NULL,
+  col_time_key time NOT NULL,
+  col_varchar_key varchar(1) NOT NULL,
+  col_varchar_nokey varchar(1) NOT NULL,
+  PRIMARY KEY (pk),
+  KEY col_int_key (col_int_key),
+  KEY col_time_key (col_time_key),
+  KEY col_varchar_key (col_varchar_key,col_int_key)
+) ENGINE=MyISAM;
+
+CREATE TABLE t2 (
+  pk int NOT NULL AUTO_INCREMENT,
+  col_int_nokey int NOT NULL,
+  col_int_key int NOT NULL,
+  col_time_key time NOT NULL,
+  col_varchar_key varchar(1) NOT NULL,
+  col_varchar_nokey varchar(1) NOT NULL,
+  PRIMARY KEY (pk),
+  KEY col_int_key (col_int_key),
+  KEY col_time_key (col_time_key),
+  KEY col_varchar_key (col_varchar_key,col_int_key)
+) ENGINE=MyISAM;
+
+INSERT INTO t2 VALUES (1,4,4,'00:00:00','b','b');
+
+SET @var2:=4, @var3:=8;
+
+--echo
+--echo Testcase without inner subquery
+
+let $subq=
+SELECT @var3:=12, sq4_alias1.*
+FROM t1 AS sq4_alias1
+WHERE (sq4_alias1.col_varchar_key + NULL) IS NULL OR
+      sq4_alias1.col_varchar_key = @var3;
+
+eval EXPLAIN $subq;
+eval $subq;
+SELECT @var3;
+
+# Now as derived table:
+eval EXPLAIN SELECT * FROM ( $subq ) AS alias3;
+eval SELECT * FROM ( $subq ) AS alias3;
+SELECT @var3;
+
+--echo
+--echo Testcase with inner subquery; crashed WL#6095
+SET @var3=8;
+let $subq=
+SELECT sq4_alias1.*
+FROM t1 AS sq4_alias1
+WHERE (sq4_alias1.col_varchar_key , sq4_alias1.col_varchar_nokey)
+      NOT IN
+      (SELECT c_sq1_alias1.col_varchar_key AS c_sq1_field1,
+              c_sq1_alias1.col_varchar_nokey AS c_sq1_field2
+       FROM t2 AS c_sq1_alias1
+       WHERE (c_sq1_alias1.col_int_nokey != @var2
+              OR c_sq1_alias1.pk != @var3));
+
+eval EXPLAIN $subq;
+eval $subq;
+# Now as derived table:
+eval EXPLAIN SELECT * FROM ( $subq ) AS alias3;
+eval SELECT * FROM ( $subq ) AS alias3;
+
+DROP TABLE t1,t2;
+
 --echo End of 5.2 tests
+

sql/sql_select.cc

@@ -1065,11 +1065,9 @@ JOIN::optimize()
     DBUG_RETURN(1);				// error == -1
   }
   if (const_table_map != found_const_table_map &&
-      !(select_options & SELECT_DESCRIBE) &&
-      (!conds ||
-       !(conds->used_tables() & RAND_TABLE_BIT) ||
-       select_lex->master_unit() == &thd->lex->unit)) // upper level SELECT
+      !(select_options & SELECT_DESCRIBE))
   {
+    // There is at least one empty const table
     zero_result_cause= "no matching row in const table";
     DBUG_PRINT("error",("Error: %s", zero_result_cause));
     error= 0;
@@ -12204,6 +12202,17 @@ int safe_index_read(JOIN_TAB *tab)
 }
 
 
+/**
+  Reads content of constant table
+
+  @param tab  table
+  @param pos  position of table in query plan
+
+  @retval 0   ok, one row was found or one NULL-complemented row was created
+  @retval -1  ok, no row was found and no NULL-complemented row was created
+  @retval 1   error
+*/
+
 static int
 join_read_const_table(JOIN_TAB *tab, POSITION *pos)
 {
@@ -12295,6 +12304,16 @@ join_read_const_table(JOIN_TAB *tab, POSITION *pos)
 }
 
 
+/**
+  Read a constant table when there is at most one matching row, using a table
+  scan.
+
+  @param tab			Table to read
+
+  @retval  0  Row was found
+  @retval  -1 Row was not found
+  @retval  1  Got an error (other than row not found) during read
+*/
 static int
 join_read_system(JOIN_TAB *tab)
 {
@@ -12326,12 +12345,9 @@ join_read_system(JOIN_TAB *tab)
 
   @param tab			Table to read
 
-  @retval
-    0	Row was found
-  @retval
-    -1   Row was not found
-  @retval
-    1   Got an error (other than row not found) during read
+  @retval  0  Row was found
+  @retval  -1 Row was not found
+  @retval  1  Got an error (other than row not found) during read
 */
 
 static int