On Tue, 2009-01-20 at 21:51 +0200, Heikki Linnakangas wrote: > Attached is a simple patch to only start skipping pages after 20 > consecutive pages marked as visible in the visibility map. This doesn't > do any "look-ahead", so it will always scan the first 20 pages of a > table before it starts to skip pages, and whenever there's even one page > that needs vacuuming, the next 19 pages will also be vacuumed. > > We could adjust that figure 20 according to table size. Or by > seq_page_cost/random_page_cost. But I'm leaning towards a simple > hard-coded value for now.
Yes, sounds good. Can we stick to multiples of 2 as the OS readahead does IIRC? So either 16 or 32. I'd go 32. -- Simon Riggs www.2ndQuadrant.com PostgreSQL Training, Services and Support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
