"Robert Haas" <[EMAIL PROTECTED]> writes: >>> Maybe. The difference is that I'm talking about converting tuples, >>> not pages, so "What happens when the data doesn't fit on the new >>> page?" is a meaningless question. >> >> No it's not, because as you pointed out you still need a way for the user to >> force it to happen sometime. Unless you're going to be happy with telling >> users they need to update all their tuples which would not be an online >> process. >> >> In any case it sounds like you're saying you want to allow multiple versions >> of tuples on the same page -- which a) would be much harder and b) doesn't >> solve the problem since the page still has to be converted sometime anyways. > > No, that's not what I'm suggesting. My thought was that any V3 page > would be treated as if it were completely full, with the exception of > a completely empty page which can be reinitialized as a V4 page. So > you would never add any tuples to a V3 page, but you would need to > update xmax, hint bits, etc. Eventually when all the tuples were dead > you could reuse the page.
But there's no guarantee that will ever happen. Heikki claimed you would need a mechanism to convert the page some day and you said you proposed a system where that wasn't true. -- Gregory Stark EnterpriseDB http://www.enterprisedb.com Ask me about EnterpriseDB's Slony Replication support! -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
