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From:V Narayanan Date:July 30 2009 10:34am
Subject:bzr commit into mysql-5.1-bugteam branch (v.narayanan:3048) Bug#45800
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#At file:///home/narayanan/Work/mysql_checkouts/shared_repository_directory/mysql-5.1-bugteam-45800-1/ based on revid:kristofer.pettersson@stripped

 3048 V Narayanan	2009-07-30
      Bug#45800 crash when replacing into a merge table and there is a duplicate
            
      A REPLACE in the MERGE engine is actually a REPLACE
      into one (FIRST or LAST) of the underlying MyISAM
      tables. So in effect the server works on the meta
      data of the MERGE table, while the real insert happens
      in the MyISAM table.
      
      The MERGE table has no index, while MyISAM has a
      unique index. When a REPLACE into a MERGE table (
      and the REPLACE conflicts with a duplicate in a
      child table) is done, we try to access the duplicate
      key information for the MERGE table. This information
      actually does not exist, hence this results in a crash.
      
      The problem can be resolved by modifying the MERGE
      engine to provide us the duplicate key information
      directly, instead of just returning the MyISAM index
      number as the error key. Then the SQL layer (or "the
      server") does not try to access the key_info of the
      MERGE table, which does not exist.
      
      The current patch modifies the MERGE engine to provide
      the position for a record where a unique key violation
      occurs.
     @ include/myisammrg.h
        Bug#45800 crash when replacing into a merge table and there is a duplicate
        
        Add a member to the st_mymerge_info structure that will
        store the duplicate key offset in the MERGE table. This
        offset will be the sum of the record offset of the MyISAM
        table within the MERGE table and the offset of the record
        within the MyISAM table.
     @ mysql-test/r/merge.result
        Bug#45800 crash when replacing into a merge table and there is a duplicate
        
        Result file for the test case.
     @ mysql-test/t/merge.test
        Bug#45800 crash when replacing into a merge table and there is a duplicate
        
        Added test case for both REPLACE and INSERT...ON DUPLICATE UPDATE.
     @ storage/myisammrg/ha_myisammrg.cc
        Bug#45800 crash when replacing into a merge table and there is a duplicate
        
        The info method now will process the HA_STATUS_ERRKEY flag
        and will return the index and the offset of the duplicate
        key.
     @ storage/myisammrg/ha_myisammrg.h
        Bug#45800 crash when replacing into a merge table and there is a duplicate
        
        Set the HA_DUPLICATE_POS flag to indicate that the duplicate
        key information is now available in the MERGE storage engine.
     @ storage/myisammrg/myrg_info.c
        Bug#45800 crash when replacing into a merge table and there is a duplicate
        
        We modify the myrg_status function to return the position of the
        duplicate key. The duplicate key position in the MERGE table will
        be the MyISAM file_offset and the offset within the MyISAM table
        of the start position of the records.

    modified:
      include/myisammrg.h
      mysql-test/r/merge.result
      mysql-test/t/merge.test
      storage/myisammrg/ha_myisammrg.cc
      storage/myisammrg/ha_myisammrg.h
      storage/myisammrg/myrg_info.c
=== modified file 'include/myisammrg.h'
--- a/include/myisammrg.h	2009-07-10 11:34:03 +0000
+++ b/include/myisammrg.h	2009-07-30 10:34:41 +0000
@@ -47,6 +47,7 @@ typedef struct st_mymerge_info		/* Struc
   ulonglong deleted;			/* Deleted records in database */
   ulonglong recpos;			/* Pos for last used record */
   ulonglong data_file_length;
+  ulonglong dupp_key_pos;               /* Offset of the Duplicate key in the merge table */
   uint	reclength;			/* Recordlength */
   int	errkey;				/* With key was dupplicated on err */
   uint	options;			/* HA_OPTION_... used */

=== modified file 'mysql-test/r/merge.result'
--- a/mysql-test/r/merge.result	2009-07-15 23:23:57 +0000
+++ b/mysql-test/r/merge.result	2009-07-30 10:34:41 +0000
@@ -2115,6 +2115,52 @@ insert into m1 (col1) values (1);
 insert into m1 (col1) values (1);
 ERROR 23000: Duplicate entry '' for key '*UNKNOWN*'
 drop table m1, t1;
+#
+# Bug#45800 crash when replacing into a merge table and there is a duplicate
+#
+# Replace duplicate value in child table when merge table doesn't have key
+CREATE TABLE t1 (c1 INT PRIMARY KEY) ENGINE=MyISAM;
+CREATE TABLE m1 (c1 INT NOT NULL) ENGINE=MRG_MyISAM INSERT_METHOD=LAST UNION=(t1);
+INSERT INTO m1  VALUES (666);
+SELECT * FROM m1;
+c1
+666
+# insert the duplicate value into the merge table
+REPLACE INTO m1 VALUES (666);
+SELECT * FROM m1;
+c1
+666
+DROP TABLE m1, t1;
+# Insert... on duplicate key update (with duplicate values in the table)
+CREATE TABLE t1 (c1 INT PRIMARY KEY) ENGINE=MyISAM;
+CREATE TABLE m1 (c1 INT NOT NULL) ENGINE=MRG_MyISAM INSERT_METHOD=LAST UNION=(t1);
+INSERT INTO m1  VALUES (666);
+SELECT * FROM m1;
+c1
+666
+# insert the duplicate value into the merge table
+INSERT INTO m1 VALUES (666) ON DUPLICATE KEY UPDATE c1=c1+1;
+SELECT * FROM m1;
+c1
+667
+DROP TABLE m1, t1;
+# Insert duplicate value on MERGE table, where, MERGE has a key but MyISAM has more keys
+CREATE TABLE t1 (c1 INT, c2 INT, UNIQUE (c1), UNIQUE (c2));
+CREATE TABLE m1 (c1 INT, c2 INT, UNIQUE (c1)) ENGINE=MRG_MyISAM INSERT_METHOD=LAST UNION=(t1);
+INSERT INTO m1 VALUES (1,2);
+# insert the duplicate value into the merge table
+INSERT INTO m1 VALUES (3,2);
+ERROR 23000: Duplicate entry '' for key '*UNKNOWN*'
+DROP TABLE m1,t1;
+# Try to define MERGE and MyISAM with keys on different columns
+CREATE TABLE t1 (c1 INT, c2 INT, UNIQUE (c1));
+CREATE TABLE m1 (c1 INT, c2 INT, UNIQUE (c2)) ENGINE=MRG_MyISAM INSERT_METHOD=LAST UNION=(t1);
+# Try accessing the merge table for inserts (error occurs)
+INSERT INTO m1 VALUES (1,2);
+ERROR HY000: Unable to open underlying table which is differently defined or of non-MyISAM type or doesn't exist
+INSERT INTO m1 VALUES (1,4);
+ERROR HY000: Unable to open underlying table which is differently defined or of non-MyISAM type or doesn't exist
+DROP TABLE m1,t1;
 CREATE TABLE t1 (
 col1 INT(10)
 ) ENGINE=MyISAM  DEFAULT CHARSET=latin1;

=== modified file 'mysql-test/t/merge.test'
--- a/mysql-test/t/merge.test	2009-07-15 23:23:57 +0000
+++ b/mysql-test/t/merge.test	2009-07-30 10:34:41 +0000
@@ -1515,6 +1515,49 @@ insert into m1 (col1) values (1);
 
 drop table m1, t1;
 
+--echo #
+--echo # Bug#45800 crash when replacing into a merge table and there is a duplicate
+--echo #
+
+--echo # Replace duplicate value in child table when merge table doesn't have key
+CREATE TABLE t1 (c1 INT PRIMARY KEY) ENGINE=MyISAM;
+CREATE TABLE m1 (c1 INT NOT NULL) ENGINE=MRG_MyISAM INSERT_METHOD=LAST UNION=(t1);
+INSERT INTO m1  VALUES (666);
+SELECT * FROM m1;
+--echo # insert the duplicate value into the merge table
+REPLACE INTO m1 VALUES (666);
+SELECT * FROM m1;
+DROP TABLE m1, t1;
+
+--echo # Insert... on duplicate key update (with duplicate values in the table)
+CREATE TABLE t1 (c1 INT PRIMARY KEY) ENGINE=MyISAM;
+CREATE TABLE m1 (c1 INT NOT NULL) ENGINE=MRG_MyISAM INSERT_METHOD=LAST UNION=(t1);
+INSERT INTO m1  VALUES (666);
+SELECT * FROM m1;
+--echo # insert the duplicate value into the merge table
+INSERT INTO m1 VALUES (666) ON DUPLICATE KEY UPDATE c1=c1+1;
+SELECT * FROM m1;
+DROP TABLE m1, t1;
+
+--echo # Insert duplicate value on MERGE table, where, MERGE has a key but MyISAM has more keys
+CREATE TABLE t1 (c1 INT, c2 INT, UNIQUE (c1), UNIQUE (c2));
+CREATE TABLE m1 (c1 INT, c2 INT, UNIQUE (c1)) ENGINE=MRG_MyISAM INSERT_METHOD=LAST UNION=(t1);
+INSERT INTO m1 VALUES (1,2);
+--echo # insert the duplicate value into the merge table
+--error ER_DUP_ENTRY
+INSERT INTO m1 VALUES (3,2);
+DROP TABLE m1,t1;
+
+--echo # Try to define MERGE and MyISAM with keys on different columns
+CREATE TABLE t1 (c1 INT, c2 INT, UNIQUE (c1));
+CREATE TABLE m1 (c1 INT, c2 INT, UNIQUE (c2)) ENGINE=MRG_MyISAM INSERT_METHOD=LAST UNION=(t1);
+--echo # Try accessing the merge table for inserts (error occurs)
+--error ER_WRONG_MRG_TABLE
+INSERT INTO m1 VALUES (1,2);
+--error ER_WRONG_MRG_TABLE
+INSERT INTO m1 VALUES (1,4);
+DROP TABLE m1,t1;
+
 #
 #Bug #44040   MySQL allows creating a MERGE table upon VIEWs but crashes 
 #when using it

=== modified file 'storage/myisammrg/ha_myisammrg.cc'
--- a/storage/myisammrg/ha_myisammrg.cc	2009-07-10 11:34:03 +0000
+++ b/storage/myisammrg/ha_myisammrg.cc	2009-07-30 10:34:41 +0000
@@ -884,7 +884,6 @@ int ha_myisammrg::info(uint flag)
     */
     mrg_info.errkey= MAX_KEY;
   }
-  errkey= mrg_info.errkey;
   table->s->keys_in_use.set_prefix(table->s->keys);
   stats.mean_rec_length= mrg_info.reclength;
   
@@ -934,6 +933,11 @@ int ha_myisammrg::info(uint flag)
              min(file->keys, table->s->key_parts));
     }
   }
+  if (flag & HA_STATUS_ERRKEY)
+  {
+    errkey= mrg_info.errkey;
+    my_store_ptr(dup_ref, ref_length, mrg_info.dupp_key_pos);
+  }
   return 0;
 }
 

=== modified file 'storage/myisammrg/ha_myisammrg.h'
--- a/storage/myisammrg/ha_myisammrg.h	2009-02-12 11:12:07 +0000
+++ b/storage/myisammrg/ha_myisammrg.h	2009-07-30 10:34:41 +0000
@@ -44,7 +44,8 @@ class ha_myisammrg: public handler
 	    HA_NULL_IN_KEY | HA_CAN_INDEX_BLOBS | HA_FILE_BASED |
             HA_ANY_INDEX_MAY_BE_UNIQUE | HA_CAN_BIT_FIELD |
             HA_HAS_RECORDS |
-            HA_NO_COPY_ON_ALTER);
+            HA_NO_COPY_ON_ALTER |
+            HA_DUPLICATE_POS);
   }
   ulong index_flags(uint inx, uint part, bool all_parts) const
   {

=== modified file 'storage/myisammrg/myrg_info.c'
--- a/storage/myisammrg/myrg_info.c	2006-12-31 00:32:21 +0000
+++ b/storage/myisammrg/myrg_info.c	2009-07-30 10:34:41 +0000
@@ -58,9 +58,27 @@ int myrg_status(MYRG_INFO *info,register
     x->reclength= info->reclength;
     x->options= info->options;
     if (current_table)
+    {
+      /*
+        errkey is set to the index number of the myisam tables. But
+        since the MERGE table can have less keys than the MyISAM
+        tables, errkey cannot be be used as an index into the key_info
+        on the server. This value will be overwritten with MAX_KEY by
+        the MERGE engine.
+      */
       x->errkey= current_table->table->errkey;
+      /*
+        Calculate the position of the duplicate key to be the sum of the
+        offset of the myisam file and the offset into the file at which
+        the duplicate key is located.
+      */
+      x->dupp_key_pos= current_table->file_offset + current_table->table->dupp_key_pos;
+    }
     else
+    {
       x->errkey= 0;
+      x->dupp_key_pos= 0;
+    }
     x->rec_per_key = info->rec_per_key_part;
   }
   DBUG_RETURN(0);


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bzr commit into mysql-5.1-bugteam branch (v.narayanan:3048) Bug#45800V Narayanan30 Jul