On Tue, Feb 12, 2019 at 4:17 PM Tom Lane <tgl@xxxxxxxxxxxxx> wrote:
Jeff Janes <jeff.janes@xxxxxxxxx> writes:
> In order for bloom (or any other users of CREATE ACCESS METHOD, if there
> are any) to have a fighting chance to do better, I think many of selfuncs.c
> currently private functions would have to be declared in some header file,
> perhaps utils/selfuncs.h. But that then requires a cascade of other
> inclusions. Perhaps that is why it was not done.
I'm just in the midst of refactoring that stuff, so if you have
suggestions, let's hear 'em.
The goal would be that I can copy the entire definition of genericcostestimate into blcost.c, change the function's name, and get it to compile. I don't know the correct way accomplish that. Maybe utils/selfuncs.h can be expanded to work, or if there should be a new header file like "utils/index_am_cost.h"
What I've done for now is:
#include "../../src/backend/utils/adt/selfuncs.c"
which I assume is not acceptable as a real solution.
It's possible that a good cost model for bloom is so far outside
genericcostestimate's ideas that trying to use it is not a good
idea anyway.
I think that might be the case. I don't know what the right answer would look like, but I think it will likely end up needing to access everything that genericcostestimate currently needs to access. Or if bloom doesn't, some other extension implementing an ACCESS METHOD will.
Cheers,
Jeff
