On Tue, Jun 14, 2011 at 7:28 PM, Bruce Momjian <bruce@momjian.us> wrote:
> Simon Riggs wrote:
>> Currently, the planner and executor are mostly independent of each
>> other: the planner doesn't really know when the plan will be executed,
>> and the executor doesn't know how recently the plan was made.
>>
>> We can work out the various paths through the traffic cop to see when
>> a plan will be a "one-shot" - planned and then executed immediately,
>> then discarded.
>
> I was also hoping someday allow plans that are to be immediately
> executed to probe the buffer cache to determine how expensive index
> scans would be.
Yes, it opens up many optimizations, both for cache sensitivity and
dynamic data access.
But those are later ideas based on the existence of this first step.
--
Simon Riggs http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services