Alterações na distribuição 4.0.9 (09 Jan 2003)
Functionality added or changed:
OPTIMIZE TABLE
will for MyISAM tables treat allNULL
values as different when calculating cardinality. This helps in optimising joins between tables where one of the tables has a lot ofNULL
values in a indexed column:SELECT * from t1,t2 where t1.a=t2.key_with_a_lot_of_null;
- Added join operator
FORCE INDEX (key_list)
. This acts likesUSE INDEX (key_list)
but with the addition that a table scan is assumed to be VERY expensive. One bad thing with this is that it makesFORCE
a reserved word. - Reset internal row buffer in MyISAM after each query. This will reduce memory in the case you have a lot of big blobs in a table.
Bugs fixed:
- A security patch in 4.0.8 causes the mysqld server to die if the remote hostname can't be resolved. This is now fixed.
- Fixed crash when replication big
LOAD DATA INFILE
statement that caused log rotation.