On Mon, 2005-10-03 at 23:51 -0400, Rod Taylor wrote: > On Mon, 2005-10-03 at 23:24 -0400, Greg Stark wrote: > > Hannu Krosing <[EMAIL PROTECTED]> writes: > > > > > On P, 2005-10-02 at 23:00 -0400, Tom Lane wrote: > > > > > > > > Here's another interesting case to think about: > > > > > > > > ALTER TABLE ADD foo integer DEFAULT 1 > > > > ... > > > > ALTER TABLE ALTER foo SET DEFAULT 2 > > > > > > > > You'll have to pay the table-traversal cost on one step or the other. > > > > > > The second, ALTER ... SET DEFAULT, would only set default for newly > > > inserted columns, not the ones which are missing due to tuples being > > > created before the column existed. > > > > Hm. So you're saying there are only ever exactly two types of defaults. The > > "initial" default that applies to all tuples that were created before the > > column was added. And the "current" default that only ever applies to newly > > created tuples. > > > > That does seem to cleanly close this hole. > > I don't think so.
Ignore me. The thread seems to be about allowing fast addition of columns, not decreasing storage space. For some reason I was thinking of a bitmap like the NULL bitmap for compressing out all default values. -- ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
