On 3 August 2015 at 17:36, Tom Lane <t...@sss.pgh.pa.us> wrote: > Alvaro Herrera <alvhe...@2ndquadrant.com> writes: > > Simon Riggs wrote: > >> * For emergency anti-wraparound VACUUMs we shouldn't scan indexes at > all, > >> since they aren't critical path activities at that point > > > It is not possible to skip scanning indexes completely, unless no tuples > > are to be removed from the heap. > > Right. > > > But actually this is an interesting point and I don't think we do this: > > if in emergency mode, maybe we shouldn't try to remove any dead tuples > > at all, and instead only freeze very old tuples. > > +1 ... not sure if that's what Simon had in mind exactly, but it seems > like a correct statement of what he was getting at. >
Yes, that's what I was thinking, I just didn't say actually it. I'd been thinking about having VACUUM do just Phase 1 for some time, since its so much faster to do that. Will code. -- Simon Riggs http://www.2ndQuadrant.com/ <http://www.2ndquadrant.com/> PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
