On 10/5/16, Andres Freund <and...@anarazel.de> wrote: > On 2016-10-05 11:58:33 -0700, Serge Rielau wrote: >> Dear Hackers, >> I’m working on a patch that expands PG’s ability to add columns to a table >> without a table rewrite (i.e. at O(1) cost) from the >> nullable-without-default to a more general case. > > If I understand this proposal correctly, altering a column default will > still have trigger a rewrite unless there's previous default?
No, "a second “exist default"" was mentioned, i.e. it is an additional column in a system table (pg_attribute) as default column values of the "pre-alter" era. It solves changing of the default expression of the same column later. -- Best regards, Vitaly Burovoy -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
