Performance impact on adding columns

From: sanjeev sharma <san-sharma_at_worldnet.att.com>
Date: 1997/03/23
Message-ID: <5h44nd$o74@mtinsc04.worldnet.att.net>#1/1

I urgently need to know. Will there be any impact on database performance if two columns ( Nullable) are added in tables of avg 15 millions rows each. If yes Will it help if I
# export the tables.
# create the table with new columns
# import the data back in new table.

In case no tx will ever update the existings rows to populate the new columns, then can i simply add the columns in the table by issuing ALTER TABLE <> add <col> command, without effecting performance of the system ?

Thanks
Sam. Received on Sun Mar 23 1997 - 00:00:00 CST