On Tue, Jun 6, 2017 at 4:05 PM, Peter Eisentraut < peter.eisentr...@2ndquadrant.com> wrote:
> On 6/6/17 08:29, Bruce Momjian wrote: > > On Tue, Jun 6, 2017 at 06:00:54PM +0800, Craig Ringer wrote: > >> Tom's point is, I think, that we'll want to stay pg_upgrade > >> compatible. So when we see a pg10 tuple and want to add a new page > >> with a new page header that has an epoch, but the whole page is full > >> so there isn't 32 bits left to move tuples "down" the page, what do we > >> do? > > > > I guess I am missing something. If you see an old page version number, > > you know none of the tuples are from running transactions so you can > > just freeze them all, after consulting the pg_clog. What am I missing? > > If the page is full, why are you trying to add to the page? > > The problem is if you want to delete from such a page. Then you need to > update the tuple's xmax and stick the new xid epoch somewhere. > > We had an unconference session at PGCon about this. These issues were > all discussed and some ideas were thrown around. We can expect a patch > to appear soon, I think. > Right. I'm now working on splitting my large patch for 64-bit xids into patchset. I'm planning to post patchset in the beginning of next week. ------ Alexander Korotkov Postgres Professional: http://www.postgrespro.com The Russian Postgres Company
