On Tue, Apr 14, 2015 at 6:07 PM, Simon Riggs <si...@2ndquadrant.com> wrote: > On 11 March 2015 at 20:55, Peter Eisentraut <pete...@gmx.net> wrote: >> I don't know how to move forward. We could give users a knob: This >> might make your queries faster or not -- good luck. But of course >> nobody will like that either. > > What is clear is that large SELECT queries are doing the work VACUUM > should do. We should not be doing large background tasks (block > cleanup) during long running foreground tasks. But there is no need > for changing behaviour during small SELECTs. So the setting of 4 gives > current behaviour for small SELECTs and new behaviour for larger > SELECTs.
Peter commented previously that README.HOT should get an update. The relevant section seems to be "When can/should we prune or defragment?". I wonder if it would be a useful heuristic to still prune pages if those pages are already dirty. -- 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
