>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]
