Re: How to construct an exact plan

Hi,
I am hacking postgresql 8.2.5. a) and b) do not work for me.

The situation is that I made a join operator, and a scan operator.
And, The join operator requires the scan operator as the inner. So, I
need to have the full control of the join plan.

I am not ready to provide the optimization support for the two new
operators. And, I want to run some performance tests before working on
the optimization part.

So, I want to know if it is possible to directly create a path or a
plan, and do a unit test for the operators.


Thanks
--
Pei

On Mon, Aug 30, 2010 at 1:59 PM, Josh Berkus <josh@agliodbs.com> wrote:
>
>> I have developed a new operators, and I want to do some tests on it.
>> I do not want the optimizer to choose the plan for me, and I need to
>> construct a plan as exact as I want.
>>
>> Can anyone provide me a way to achieve that?
>
> a) easy: choose a simple enough query that its plan is always predictable.
>
> b) moderate: choose a query whose plan is predictable if you manipulate
> the enable_* configuration settings
>
> c) hard: hack the PostgreSQL planner to choose a specific execution
> plan, and recompile Postgres.
>
> --
>                                  -- Josh Berkus
>                                     PostgreSQL Experts Inc.
>                                     http://www.pgexperts.com
>