Tom Lane wrote:
Simon Riggs <[EMAIL PROTECTED]> writes:
On Thu, 2008-06-26 at 12:36 -0400, Robert Haas wrote:
It's my understanding that the philosophy of the PGDG in the past has
been to avoid putting any kind of hints into the system, focusing
rather an improving the planning of queries.
It's not a specific hint, its a general goal setting.
Right. There are definitely places where we've made engineering
judgements to not attempt a particular type of optimization because it'd
be too expensive compared to the typical payoff. Simon's idea has some
merit for providing a framework to deal with that type of situation.
However, just adding a GUC variable isn't going to make anything happen
--- we'd need some concrete plans about what we'd do with it.
If the planner provided some facility to control how much effort it puts
into planning, we could even tune that knob automatically with something
like
plan = plan_query(effort=0);
if (estimated_execution_cost > triviality_threshold)
plan = plan_query(estimated_execution_cost * effort_by_cost_ratio);
regards, Forian Pflug
--
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers
