From: Roy Lyseng
Date: October 27 2011 11:41am
Subject: bzr push into mysql-trunk branch (roy.lyseng:3470 to 3471) Bug#13106350
List-Archive: http://lists.mysql.com/commits/141608
X-Bug: 13106350
Message-Id: <20111027114158.2B5ED203@tyr67.norway.sun.com>
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 3471 Roy Lyseng	2011-10-27
      Bug#13106350: MRR initialization on a derived table caused crash
      
      Followup patch to make test behave in trunk.
      
      mysql-test/r/derived.result
        Updated result file for bug#13106350.
      
      mysql-test/t/derived.test
        Deleted setting of semi-join related optimizer switches.
        Added explain to notify of plan changes.

    modified:
      mysql-test/r/derived.result
      mysql-test/t/derived.test
 3470 Roy Lyseng	2011-10-26
      Bug#113106350: crash in memcpy from join_cache::write_record_data
      
      This problem may happen if we combine the Duplicate Weedout semi-join
      strategy with join buffering, and the outer table is a derived table.
      
      The problem is that Duplicate Weedout needs the row id of all involved
      tables, hence the table is instructed to save the row id.
      Join buffering needs to save and restore the rowid into a buffer,
      for that purpose an st_cache_field object is allocated. This object
      contains a pointer to the row id buffer, but at the time of object
      creation, the table (being a derived table) has not yet been opened
      and the buffer pointer is NULL.
      
      The fix is to save a reference to the st_cache_field object in the
      corresponding JOIN_TAB and bind it with the buffer after the derived
      table has been materialized.
      
      mysql-test/t/derived.test
        Added test case for bug#113106350.
      
      mysql-test/r/derived.result
        Added test case results for bug#113106350.
      
      sql/sql_join_cache.cc
        Save reference to rowid copy object when setting up fields to copy.
      
      sql/sql_select.cc
        Bind the rowid buffer of a TABLE object to a copy object that is
        used to copy a rowid. Needed when temporary tables are opened
        as part of execution.
        
      sql/sql_select.h
        Added reference to copy object used to copy rowid in JOIN_TAB.
        Added a bind_buffer() access function for st_cache_field.

    modified:
      mysql-test/r/derived.result
      mysql-test/t/derived.test
      sql/sql_join_cache.cc
      sql/sql_select.cc
      sql/sql_select.h
=== modified file 'mysql-test/r/derived.result'
--- a/mysql-test/r/derived.result	2011-10-26 13:23:01 +0000
+++ b/mysql-test/r/derived.result	2011-10-27 11:39:49 +0000
@@ -1617,14 +1617,22 @@ DROP TABLE t1, t2;
 #
 # Bug#13106350: MRR initialization on a derived table caused crash.
 #
-SET @save_switch= @@optimizer_switch;
-SET @@optimizer_switch="firstmatch=off,loosescan=off,materialization=off";
 CREATE TABLE t1 (pk INTEGER PRIMARY KEY, vc VARCHAR(20));
 INSERT INTO t1 VALUES(7, 'seven'), (13, 'thirteen');
 CREATE TABLE t2 (pk INTEGER PRIMARY KEY, vc1 VARCHAR(20), vc2 VARCHAR(20));
 INSERT INTO t2 VALUES(7, 'seven', 's'), (14, 'fourteen', 'f');
 CREATE TABLE t3 (pk INTEGER PRIMARY KEY, vc VARCHAR(20));
 INSERT INTO t3 VALUES(5, 'f'), (6, 's'), (7, 's');
+explain SELECT derived.vc
+FROM (SELECT * FROM t1) AS derived
+WHERE derived.vc IN (
+SELECT t2.vc1
+FROM t2 JOIN t3 ON t2.vc2=t3.vc);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where; Start temporary
+1	PRIMARY	<derived2>	ref	auto_key0	auto_key0	23	test.t2.vc1	2	
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	Using where; End temporary; Using join buffer (Block Nested Loop)
+2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	2	
 SELECT derived.vc
 FROM (SELECT * FROM t1) AS derived
 WHERE derived.vc IN (
@@ -1632,6 +1640,5 @@ SELECT t2.vc1
 FROM t2 JOIN t3 ON t2.vc2=t3.vc);
 vc
 seven
-SET @@optimizer_switch= @save_switch;
 DROP TABLE t1, t2, t3;
 #

=== modified file 'mysql-test/t/derived.test'
--- a/mysql-test/t/derived.test	2011-10-26 13:23:01 +0000
+++ b/mysql-test/t/derived.test	2011-10-27 11:39:49 +0000
@@ -979,8 +979,6 @@ DROP TABLE t1, t2;
 --echo #
 --echo # Bug#13106350: MRR initialization on a derived table caused crash.
 --echo #
-SET @save_switch= @@optimizer_switch;
-SET @@optimizer_switch="firstmatch=off,loosescan=off,materialization=off";
 
 CREATE TABLE t1 (pk INTEGER PRIMARY KEY, vc VARCHAR(20));
 
@@ -994,13 +992,15 @@ CREATE TABLE t3 (pk INTEGER PRIMARY KEY,
 
 INSERT INTO t3 VALUES(5, 'f'), (6, 's'), (7, 's');
 
+let $query=
 SELECT derived.vc
 FROM (SELECT * FROM t1) AS derived
 WHERE derived.vc IN (
   SELECT t2.vc1
   FROM t2 JOIN t3 ON t2.vc2=t3.vc);
+eval explain $query;
+eval $query;
 
-SET @@optimizer_switch= @save_switch;
 DROP TABLE t1, t2, t3;
 
 --echo #

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