On Thu, May 27, 2004 at 09:52:30PM +0200, Manfred Koizar wrote: > I have no clear explanation at the moment, just some fuzzy ideas that > are beginning to crystallise. I'm messing around with heap tuple > headers again, and the Xvac field seems to get in the way, unless I can > cut down the number of different scenarios where it is needed.
Now you are on the subject, can I ask you to take a peek at what I did regarding tuple headers? At first I thought I'd have to add back Xmax as a field on its own, but later (in chat with Bruce) I arrived to the conclusion that it isn't really necessary, and I only added a bit to the infomask to flag when the Cmin is overridden with Xmax. However I'm not convinced that this is enough --- is there a situation on which we should need to peek at Cmin after setting Xmax for a particusar tuple? The problem was BEGIN; insert into foo values (1) begin delete from foo rollback -- at this point the tuple shold be visible, -- but it has my Xid as Xmin and Cmin was -- overriden with Xmax commit I'd appreciate your (Manfred's and Tom's) comments on the topic. -- Alvaro Herrera (<alvherre[a]dcc.uchile.cl>) "And as an added bonus, now my computer goes to the toilet for me, leaving me free to spend time on more useful activities! yay slug codefests!" (C. Parker) ---------------------------(end of broadcast)--------------------------- TIP 4: Don't 'kill -9' the postmaster