> > This extreme slowness in dropping a simple index in > > MySQL defeats the whole strategy of dropping indexes > > on some tables before a huge insert operation. > > See http://dev.mysql.com/doc/mysql/en/alter-table.html , > especially these bits: > > "Note that if you use any other option to ALTER TABLE than > RENAME, MySQL always creates a temporary table, even if the data > wouldn't strictly need to be copied (such as when you change the > name of a column). We plan to fix this in the future, but > because ALTER TABLE is not a statement that is normally used > frequently, this isn't high on our TODO list." > > "As of MySQL 4.0, this feature can be activated explicitly. > ALTER TABLE ... DISABLE KEYS tells MySQL to stop updating > non-unique indexes for a MyISAM table. ALTER TABLE ... ENABLE > KEYS then should be used to re-create missing indexes. MySQL > does this with a special algorithm that is much faster than > inserting keys one by one, so disabling keys before performing > bulk insert operations should give a considerable speedup." > > You want to DISABLE, not DROP, the keys.
Which, btw, is very misleading -- non-unique indices are NOT keys. They're indices. I would only consider unique constraints and primary key constraints actual keys. :-) With regards, Martijn Tonies Database Workbench - developer tool for InterBase, Firebird, MySQL & MS SQL Server Upscene Productions http://www.upscene.com -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
