> -----Original Message----- > From: Rob Wultsch [mailto:wult...@gmail.com] > Sent: Thursday, August 05, 2010 6:05 PM > To: Daevid Vincent > Cc: MySQL List > Subject: Re: Possible tricks to ALTER on huge tables? > > Having significant amount of overhead for unused columns will without > doubt harm performance significantly for certain operations.
I don't see this as "significant overhead". A few "null" columns that are dormant are not going to impact performance in any measurable way I don't think. > Altering .frm files should is always be tried on a non-prod box before > even considering using it on prod. Thanks Capt'n Obvious. ;-p Isn't that the case for ANY and ALL DB operations? > There are some well known use cases > (adding enums values, enlarging varchar columns) where altering a .frm > is useful, but it should always be considered very dangerous. Of course. > You could of course consider using PostgreSQL which would only need a > very brief exclusive lock for adding a default null column... ...an interesting thought. -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql?unsub=arch...@jab.org
