Re: patch: SQL/MED(FDW) DDL

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> On Tue, Oct 5, 2010 at 11:06 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> IMO this is a *clear* case of premature optimization being the root of
>> all evil. We should get it working first and then see what needs to be
>> optimized by measuring, rather than guessing in a vacuum.

> I have no problem with punting the issue of remote statistics to some
> time in the future. But I don't think we should have a half-baked
> implementation of remote statistics. We should either do it right
> (doing such testing as is necessary to establish what that means) or
> not do it at all. Frankly, if we could get from where we are today to
> a workable implementation of this technology for CSV files in time for
> 9.1, I think that would be an impressive accomplishment. Making it
> work for more complicated cases is almost certainly material for 9.2,
> 9.3, 9.4, and maybe further out than that.

I quite agree that it's going to take multiple release cycles to have
a really impressive version of SQL/MED. What I'm saying is that caching
remote statistics is several versions out in my view of the world, and
designing support for it shouldn't be happening now.

Maybe we ought to take a step back and discuss what the development plan
ought to be, before we spend more time on details like this. My idea of
a good development process would involve working in parallel on at least
two FDW adapters, so that we don't find we've skewed the API design to
meet the needs of just one adapter. Probably a remote-PG adapter and a
local-CSV-file adapter would be a good combination. I don't have any
clear idea of how soon we might expect to see how much functionality,
though. Thoughts?

regards, tom lane