From: Ole John Aske
Date: January 14 2011 11:14am
Subject: bzr push into mysql-5.1-telco-7.0 branch (ole.john.aske:4107 to 4108)
 Bug#58422
List-Archive: http://lists.mysql.com/commits/128722
X-Bug: 58422
Message-Id: <20110114111458.9AEA7223@fimafeng09.norway.sun.com>
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 4108 Ole John Aske	2011-01-14
      Backport to mysql-5.1-telco-7.0:
      Fix for bug#58422: Incorrect result when OUTER JOIN'ing with an empty table
            
      Fixed incorrect checks in join_read_const_table() for when to 
      accept a non-existing, or empty const-row as a part of the
      const'ified set of tables.
            
      Intention of this test is to only accept NULL-rows if this table
      is outer joined into the resultset. (In case of an inner-join
      we can conclude at this point thatresultset will be empty,
      and we want to return 'error' to signal this.)
            
      Initially 'maybe_null' is set to the same value as 'outer_join'
      in setup_table_map(), mysql_priv.h ~line 2424. Later
      simplify_joins() will attemp to replace outer joins by inner 
      join whenever possible.
      
      This will cause 'outer_join' to be updated. However, 'maybe_null'
      is *not* updated to reflect this rewrite as this field is used 
      to currectly set the 'nullability' property for the columns 
      in the resultset.
            
      We should therefore change join_read_const_table() to check the
      'outer_join' property instead of 'maybe_null', as this correctly
      reflect the nullability of the partial *execution plan* (not *resultset*).

    modified:
      mysql-test/r/select.result
      mysql-test/t/select.test
      sql/sql_select.cc
 4107 Ole John Aske	2011-01-14
      Backport to mysql-5.1-telco-7.0:
      Fix for bug#58134: 'Incorrectly condition pushdown inside subquery to NDB engine'
            
      An incorrect 'table_map' containing both the table itself, 
      and possible any outer-refs if this was the last table in 
      the subquery, was presented to make_cond_for_table().
                  
      As a pushed condition is only able to refer column from the table
      the condition is pushed to, nothing else than columns from the
      table itself (tab->table->map) may be refered in the pushed
      condition
      constructed by 'push_cond= make_cond_for_table()'. 
                  
      Also fix a minor 'copy and paste' bug in a comment 
      in make_cond_for_table().
            

    modified:
      mysql-test/suite/ndb/r/ndb_condition_pushdown.result
      mysql-test/suite/ndb/t/ndb_condition_pushdown.test
      sql/sql_select.cc
=== modified file 'mysql-test/r/select.result'
--- a/mysql-test/r/select.result	2010-06-24 08:00:48 +0000
+++ b/mysql-test/r/select.result	2011-01-14 11:14:26 +0000
@@ -4797,4 +4797,68 @@ SELECT 1 FROM t1 ORDER BY a COLLATE lati
 1
 1
 DROP TABLE t1;
+#
+# Bug #58422: Incorrect result when OUTER JOIN'ing 
+# with an empty table
+#
+CREATE TABLE t_empty(pk INT PRIMARY KEY, i INT) ENGINE = MYISAM;
+CREATE TABLE t1(pk INT PRIMARY KEY, i INT) ENGINE = MYISAM;
+INSERT INTO t1 VALUES (1,1), (2,2), (3,3);
+CREATE TABLE t2(pk INT PRIMARY KEY, i INT) ENGINE = MYISAM;
+INSERT INTO t2 VALUES (1,1), (2,2), (3,3);
+EXPLAIN
+SELECT *
+FROM 
+t1
+LEFT OUTER JOIN
+(t2 INNER JOIN t_empty ON TRUE)
+ON t1.pk=t2.pk
+WHERE t2.pk <> 2;
+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 *
+FROM 
+t1
+LEFT OUTER JOIN
+(t2 INNER JOIN t_empty ON TRUE)
+ON t1.pk=t2.pk
+WHERE t2.pk <> 2;
+pk	i	pk	i	pk	i
+EXPLAIN
+SELECT *
+FROM 
+t1
+LEFT OUTER JOIN
+(t2 CROSS JOIN t_empty)
+ON t1.pk=t2.pk
+WHERE t2.pk <> 2;
+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 *
+FROM 
+t1
+LEFT OUTER JOIN
+(t2 CROSS JOIN t_empty)
+ON t1.pk=t2.pk
+WHERE t2.pk <> 2;
+pk	i	pk	i	pk	i
+EXPLAIN
+SELECT *
+FROM 
+t1
+LEFT OUTER JOIN
+(t2 INNER JOIN t_empty ON t_empty.i=t2.i)
+ON t1.pk=t2.pk
+WHERE t2.pk <> 2;
+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 *
+FROM 
+t1
+LEFT OUTER JOIN
+(t2 INNER JOIN t_empty ON t_empty.i=t2.i)
+ON t1.pk=t2.pk
+WHERE t2.pk <> 2;
+pk	i	pk	i	pk	i
+DROP TABLE t1,t2,t_empty;
 End of 5.1 tests

=== modified file 'mysql-test/t/select.test'
--- a/mysql-test/t/select.test	2010-06-24 17:13:08 +0000
+++ b/mysql-test/t/select.test	2011-01-14 11:14:26 +0000
@@ -4088,4 +4088,74 @@ SELECT 1 FROM t1 ORDER BY a COLLATE lati
 DROP TABLE t1;
 
 
+
+--echo #
+--echo # Bug #58422: Incorrect result when OUTER JOIN'ing 
+--echo # with an empty table
+--echo #
+
+CREATE TABLE t_empty(pk INT PRIMARY KEY, i INT) ENGINE = MYISAM;
+CREATE TABLE t1(pk INT PRIMARY KEY, i INT) ENGINE = MYISAM;
+INSERT INTO t1 VALUES (1,1), (2,2), (3,3);
+CREATE TABLE t2(pk INT PRIMARY KEY, i INT) ENGINE = MYISAM;
+INSERT INTO t2 VALUES (1,1), (2,2), (3,3);
+
+EXPLAIN
+SELECT *
+  FROM 
+    t1
+  LEFT OUTER JOIN
+    (t2 INNER JOIN t_empty ON TRUE)
+  ON t1.pk=t2.pk
+  WHERE t2.pk <> 2;
+
+SELECT *
+  FROM 
+    t1
+  LEFT OUTER JOIN
+    (t2 INNER JOIN t_empty ON TRUE)
+  ON t1.pk=t2.pk
+  WHERE t2.pk <> 2;
+
+
+EXPLAIN
+SELECT *
+  FROM 
+    t1
+  LEFT OUTER JOIN
+    (t2 CROSS JOIN t_empty)
+  ON t1.pk=t2.pk
+  WHERE t2.pk <> 2;
+
+SELECT *
+  FROM 
+    t1
+  LEFT OUTER JOIN
+    (t2 CROSS JOIN t_empty)
+  ON t1.pk=t2.pk
+  WHERE t2.pk <> 2;
+
+
+EXPLAIN
+SELECT *
+  FROM 
+    t1
+  LEFT OUTER JOIN
+    (t2 INNER JOIN t_empty ON t_empty.i=t2.i)
+  ON t1.pk=t2.pk
+  WHERE t2.pk <> 2;
+
+SELECT *
+  FROM 
+    t1
+  LEFT OUTER JOIN
+    (t2 INNER JOIN t_empty ON t_empty.i=t2.i)
+  ON t1.pk=t2.pk
+  WHERE t2.pk <> 2;
+
+
+
+DROP TABLE t1,t2,t_empty;
+
+
 --echo End of 5.1 tests

=== modified file 'sql/sql_select.cc'
--- a/sql/sql_select.cc	2011-01-14 10:42:53 +0000
+++ b/sql/sql_select.cc	2011-01-14 11:14:26 +0000
@@ -11788,7 +11788,11 @@ join_read_const_table(JOIN_TAB *tab, POS
       /* Mark for EXPLAIN that the row was not found */
       pos->records_read=0.0;
       pos->ref_depend_map= 0;
+#ifndef MCP_BUG58422
+      if (!table->pos_in_table_list->outer_join || error > 0)
+#else
       if (!table->maybe_null || error > 0)
+#endif
 	DBUG_RETURN(error);
     }
   }
@@ -11809,7 +11813,11 @@ join_read_const_table(JOIN_TAB *tab, POS
       /* Mark for EXPLAIN that the row was not found */
       pos->records_read=0.0;
       pos->ref_depend_map= 0;
+#ifndef MCP_BUG58422
+      if (!table->pos_in_table_list->outer_join || error > 0)
+#else
       if (!table->maybe_null || error > 0)
+#endif
 	DBUG_RETURN(error);
     }
   }

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