Re: Slow GRANT ROLE on PostgreSQL 16 with thousands of ROLEs - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Slow GRANT ROLE on PostgreSQL 16 with thousands of ROLEs
Date
Msg-id 2490242.1711379319@sss.pgh.pa.us
Whole thread Raw
In response to Re: Slow GRANT ROLE on PostgreSQL 16 with thousands of ROLEs  (Nathan Bossart <nathandbossart@gmail.com>)
Responses Re: Slow GRANT ROLE on PostgreSQL 16 with thousands of ROLEs
List pgsql-hackers
Nathan Bossart <nathandbossart@gmail.com> writes:
> Are there any changes you'd like to see for the Bloom patch [0]?  I'd like
> to see about getting that committed for v17.  One thing that crossed my
> mind is creating a combined list/filter that transparently created a filter
> when necessary (for reuse elsewhere), but I'm not sure that's v17 material.

Yeah, that thought occurred to me too, but I think we ought to have a
few more use-cases in view before trying to write an API.

As for the patch, I agree it could go into v17, but I think there is
still a little bit of work to do:

* The magic constants (crossover list length and bloom filter size)
need some testing to see if there are better values.  They should
probably be made into named #defines, too.  I suspect, with little
proof, that the bloom filter size isn't particularly critical --- but
I know we pulled the crossover of 1000 out of thin air, and I have
no certainty that it's even within an order of magnitude of being a
good choice.

* Code needs more than zero comments.

* Is it worth trying to make a subroutine, or at least a macro,
so as not to have 2 copies of the code?

            regards, tom lane



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