On Thu, 27 May 2004 14:23:07 -0400, Tom Lane <[EMAIL PROTECTED]> wrote: >> and when y is updated the new version will be stored in a lower block > >Oh? What makes you think that? I see no guarantee of it.
You're right, I see only a tendency, because the majority of free space is before the last block (obviously). But don't we try to store the new version on the same block as the old version? That'd weaken my argument a bit. >I think you'd have to not move *any* updated >tuples to be sure you don't need the chain-move mechanism. Yes, per definitionem (move only tuples that are visible to all). >I'm disinclined to mess with VACUUM FULL without a clearer explanation >of where you're headed. Have no fear. I won't change anything in the near term. As you were talking about the future of VACUUM FULL, I thought this might be a good opportunity to ask. The fact that you didn't outright reject the idea is good enough for now. 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. Servus Manfred ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
