Alvaro Herrera <alvherre@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.
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Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services