On Sat, Aug 6, 2011 at 7:29 PM, Dimitri Fontaine <dimi...@2ndquadrant.fr> wrote: > Tom Lane <t...@sss.pgh.pa.us> writes: >> I think we'll be a lot better off with the framework discussed last >> year: build a generic plan, as well as custom plans for the first few >> sets of parameter values, and then observe whether there's a significant >> reduction in estimated costs for the custom plans. > > Another way here would be to cache more than a single plan and to keep > execution time samples or some other relevant runtime characteristics. > Then what we need would be a way to switch from a plan to another at run > time on some conditions, like realizing that the reason why the planner > thought a nestloop would be perfect is obviously wrong, or maybe just > based on runtime characteristics.
Tom and I discussed storing multiple sub-plans on a node back in '05 IIRC, and Tom later put in support for that. That wasn't followed up on. -- Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
