On 9/21/07, Tom Lane <[EMAIL PROTECTED]> wrote: > > > > I'm also starting to come around to liking the page-header-xid field > a bit more. I suggest that it could replace the "page is prunable" > flag bit altogether --- to mark the page prunable, you must store > some appropriate xid into the header field. This would avoid a useless > prune attempt immediately after a page is marked prunable. > > Agree. I was thinking of minimum of the following:
1 xmin of INSERT_IN_PROGRESS tuple 2 xmax of DELETE_IN_PROGRESS tuple 3 xmax of RECENTLY_DEAD_TUPLE When we attempt a prune, we can set xid to the minimum of the above three. If none of the above tuples exist in the page, xid can be set to FrozenXid A page need not be pruned if its xid is set to FrozenXid or is greater than OldtestXmin. In addition, I guess we can even set the xid also when we insert, delete or update from the page unless its already set to a lower value. Thanks, Pavan -- Pavan Deolasee EnterpriseDB http://www.enterprisedb.com
