On 11/13/07, Benilton Carvalho <[EMAIL PROTECTED]> wrote: > Then each column is added on the fly, using: > > ALTER TABLE table ADD COLUMN colunm REAL; > > The columns in then filled used UPDATE as described previously.
I haven't investigated the storage layout of this, but from what the docs imply, I suspect making use of ADD COLUMN will result in SELECTs being as slow as UPDATEs, possibly worse. When I said I expect the final queries to be faster, I was envisioning all of the columns created initially, just filled with zeros. I suspect filling them with NULL initially would make update performance worse also. I'll let others confirm/deny this, and comment on the performance of ADD COLUMN in general. ----------------------------------------------------------------------------- To unsubscribe, send email to [EMAIL PROTECTED] -----------------------------------------------------------------------------
