-----BEGIN PGP SIGNED MESSAGE----- Hash: RIPEMD160 Justin Julicher asked: > We need to widen a column on a table with millions of rows and the only way > to do this currently is to migrate the data from one column to another with > a script and trigger. Not the only way - the canonical way is to simply use ALTER TABLE. > I know how to do this via an update to pg_attribute which would incur the > table scan penalty but I have a number of questions No, there is no table scan penalty. > - Does postgres pick up this change straight away? Not sure exactly what you mean. Certainly, new inserts will respect the change. > Are there any caveats to my first question? Yes. A direct pg_attribute change should be your last resort. Do an ALTER TABLE if you can. If you must do it via pg_attribute, test it very well first, and make sure to look at pg_depend. See: http://blog.endpoint.com/2012/11/postgres-alter-column-problems-and.html - -- Greg Sabino Mullane greg@xxxxxxxxxxxx greg@xxxxxxxxxxxx End Point Corporation 610-983-9073 PGP Key: 0x14964AC8 201211300113 http://biglumber.com/x/web?pk=2529DF6AB8F79407E94445B4BC9B906714964AC8 -----BEGIN PGP SIGNATURE----- iEYEAREDAAYFAlC4TtMACgkQvJuQZxSWSsiVDwCcCFYggG7mMf45nMIfoXHBGnMq TMkAn23VUHK0z/SshzrRACW0+dn5wqPv =CAQa -----END PGP SIGNATURE----- -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
