On Thu, Dec 20, 2012 at 4:58 AM, Simon Riggs <si...@2ndquadrant.com> wrote: > ISTM that if someone spots a block that could use cleanup, they mark > the block as BM_PIN_COUNT_WAITER, but don't set pid. Then when they > unpin the block they send a signal/queue work for a special cleaning > process to come in and do the work now that nobody is waiting. Logic > would allow VACUUMs to go past that by setting the pid. If we > prioritised cleanup onto blocks that are already dirty we would > minimise I/O.
I don't favor that particular signaling mechanism, but I agree that there is quite a bit of potential utility in having foreground processes notice that work (like a HOT prune, or setting the VM bit) needs to be done and pass those requests off to a background process. I'm hoping the new background worker framework in 9.3 will make that sort of thing easier for people to play around with. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
