Tom Lane wrote: > "Heikki Linnakangas" <[EMAIL PROTECTED]> writes: >> Bruce Momjian wrote: >>> This might be a simplistic question but if the page is +90% full and >>> there is a long-lived transaction, isn't Postgres going to try pruning >>> on each page read access? > >> Yes :( > > It shouldn't, though --- the hint bit should get cleared on the first > try.
Think so? That would mean that you only get a single chance to prune after an update. Not sure how big a problem that is, but I do feel that would make HOT a lot less effective in some usage patterns. The idea of having a "prunable xmin" in the page header sounds more and more attractive to me... > I think I probably broke something in the last round of revisions > to heap_page_prune_opt, but haven't looked yet ... Pavan's patch was like that as well; you don't clear the flag (or rather, you set it again while pruning) until there's nothing left to prune on the page. -- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster
