Re: Patch: ResourceOwner optimization for tables with many partitions

On Wed, Dec 9, 2015 at 8:30 AM, Aleksander Alekseev
<a(dot)alekseev(at)postgrespro(dot)ru> wrote:
> Hello, Robert
>
> Thanks for your review. I believe I fixed items 1, 2 and 3 (see
> attachment). Also I would like to clarify item 4.
>
>> 4. It mixes together multiple ideas in a single patch, not only
>> introducing a hashing concept but also striping a brand-new layer of
>> abstraction across the resource-owner mechanism. I am not sure that
>> layer of abstraction is a very good idea, but if it needs to be done,
>> I think it should be a separate patch.
>
> Do I right understand that you suggest following?
>
> Current patch should be split in two parts. In first patch we create
> and use ResourceArray with array-based implementation (abstraction
> layer). Then we apply second patch which change ResourceArray
> implementation to hashing based (optimization).

Well, sorta. To be honest, I think this patch is really ugly. If we
were going to do this then, yes, I would want to split the patch into
two parts along those lines. But actually I don't really want to do
it this way at all. It's not that I don't want the performance
benefits: I do. But the current code is really easy to read and
extremely simple, and this changes it into something that is a heck of
a lot harder to read and understand. I'm not sure exactly what to do
about that, but it seems like a problem.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company