Thanks for your patient replay. This means the myisam_max_sort_file_size is the limitation of myisam_sort_buffer_size. And they are both implemented to improve the DDL statements.
On Fri, Oct 31, 2008 at 11:45 PM, Jake Maul <[EMAIL PROTECTED]> wrote: > From dev.mysql.com: > > myisam_max_sort_file_size : > The maximum size of the temporary file that MySQL is allowed to use > while re-creating a MyISAM index (during REPAIR TABLE, ALTER TABLE, or > LOAD DATA INFILE). If the file size would be larger than this value, > the index is created using the key cache instead, which is slower. The > value is given in bytes. The default value is 2GB. If MyISAM index > files exceed this size and disk space is available, increasing the > value may help performance. > > myisam_sort_buffer_size: > The size of the buffer that is allocated when sorting MyISAM indexes > during a REPAIR TABLE or when creating indexes with CREATE INDEX or > ALTER TABLE. The maximum allowable setting for myisam_sort_buffer_size > is 4GB. (Default is 8MB) > > > Simply: one's a buffer, one's a limit on the temp file size used for > sorting. Which you might need to increase depends entirely on which > limitation you're running into... if the current index files for the > relevant tables on disk exceed 2GB, you might want to increase > myisam_max_sort_file_size. Otherwise, myisam_sort_buffer_size might be > better. > > Jake > > On Fri, Oct 31, 2008 at 12:20 AM, Moon's Father > <[EMAIL PROTECTED]> wrote: > > Because alter table and repair table are both affected by > > myisam_sort_buffer_size or myisam_max_sort_file_size, I'm in confusion > then. > > > > Anybody can tell me which to be adjusted when I want to improve the > > performance of my index operation. > > Thanks. > > > > -- > > I'm a MySQL DBA in china. > > More about me just visit here: > > http://yueliangdao0608.cublog.cn > > > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe: > http://lists.mysql.com/[EMAIL PROTECTED] > > -- I'm a MySQL DBA in china. More about me just visit here: http://yueliangdao0608.cublog.cn
