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2 commits

Author SHA1 Message Date
Jorgen Loland
5a0e7394a5 BUG#11882110: UPDATE REPORTS ER_KEY_NOT_FOUND IF TABLE IS
UPDATED TWICE

For multi update it is not allowed to update a column
of a table if that table is accessed through multiple aliases
and either
1) the updated column is used as partitioning key
2) the updated column is part of the primary key 
   and the primary key is clustered

This check is done in unsafe_key_update().

The bug was that for case 2), it was checked whether
updated_column_number == table_share->primary_key 
However, the primary_key variable is the index number of the 
primary key, not a column number.

Prior to this bugfix, the first column was wrongly believed to be
the primary key. The columns covered by an index is found in
table->key_info[idx_number]->key_part. The bugfix is to check if
any of the columns in the keyparts of the primary key are
updated.

The user-visible effect is that for storage engines with
clustered primary key (e.g. InnoDB but not MyISAM) queries
like 
"UPDATE t1 AS A JOIN t2 AS B SET A.primkey=..."
will now error with 
"ERROR HY000: Primary key/partition key update is not allowed 
since the table is updated both as 'A' and 'B'." 
instead of 
"ERROR 1032 (HY000): Can't find record in 't1_tb'"
even if primkey is not the first column in the table. This 
was the intended behavior of bugfix 11764529.


mysql-test/r/multi_update.result:
  Add test for bug#11882110
mysql-test/r/multi_update_innodb.result:
  Add test for bug#11882110
mysql-test/t/multi_update.test:
  Add test for bug#11882110
mysql-test/t/multi_update_innodb.test:
  Add test for bug#11882110
sql/sql_update.cc:
  unsafe_key_update() wrongly checked if the primary key index
  number was the same as updated column number. Now it is checked
  whether any of the columns making up the primary key is updated.
sql/table.h:
  Fix comment on TABLE_SHARE::primary_key. Incorrect comment
  was introduced by an earlier merge conflict (as per dlenev)
2011-06-16 08:24:00 +02:00
Jorgen Loland
d1d166875a BUG#11762751: UPDATE STATEMENT THROWS AN ERROR, BUT STILL
UPDATES THE TABLE ENTRIES (formerly 55385)
BUG#11764529: MULTI UPDATE+INNODB REPORTS ER_KEY_NOT_FOUND 
              IF A TABLE IS UPDATED TWICE (formerly 57373)
            
If multiple-table update updates a row through two aliases and
the first update physically moves the row, the second update will
fail to locate the row. This results in different errors
depending on storage engine:
  * MyISAM: Got error 134 from storage engine
  * InnoDB: Can't find record in 'tbl'
None of these errors accurately describe the problem. 
      
Furthermore, since MyISAM is non-transactional, the update
executed first will be performed while the second will not.
In addition, for two equal multiple-table update statements,
one could succeed and the other fail based on whether or not
the record actually moved or not. This was inconsistent.
      
Two update operations may physically move a row:
  1) Update of a column in a clustered primary key
  2) Update of a column used to calculate which partition the 
     row belongs to
           
BUG#11764529 is about case 1) above, BUG#11762751 was about case 2).
      
The fix for these bugs is to return with an error if multiple-table 
update is about to:
  a) Update a table through multiple aliases, and
  b) Perform an update that may physically more the row 
     in at least one of these aliases
    
This avoids 
  * partial updates as described for MyISAM above,
  * provides the same error message that describes the actual problem
    for all SEs
  * inconsistent behavior where a statement fails or succeeds based on
    e.g. the partitioning algorithm of the table.

mysql-test/r/multi_update.result:
  Add test for bug#57373
mysql-test/r/multi_update_innodb.result:
  Add test for bug#57373
mysql-test/r/partition.result:
  Add test for bug#55385
mysql-test/t/multi_update.test:
  Add test for bug#57373
mysql-test/t/multi_update_innodb.test:
  Add test for bug#57373
mysql-test/t/partition.test:
  Add test for bug#55385
sql/handler.cc:
  Translate handler error HA_ERR_RECORD_DELETED to server error
sql/share/errmsg-utf8.txt:
  New error message for multi-table update where the same table is updated multiple times.
sql/sql_update.cc:
  Add function unsafe_key_update()
2011-02-21 16:49:03 +01:00