Horton

Re: reducing the footprint of ScanKeyword (was Re: Large writable variables)

John Naylor <john.naylor@2ndquadrant.com>

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From: John Naylor <john.naylor@2ndquadrant.com>
To: Andrew Dunstan <andrew.dunstan@2ndquadrant.com>
Cc: Andres Freund <andres@anarazel.de>, Tom Lane <tgl@sss.pgh.pa.us>, Joerg Sonnenberger <joerg@bec.de>, David Rowley <david.rowley@2ndquadrant.com>, John Naylor <jcnaylor@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2019-01-08T18:41:16Z
Lists: pgsql-hackers 
On Tue, Jan 8, 2019 at 12:06 PM Andrew Dunstan
<andrew.dunstan@2ndquadrant.com> wrote:
> On 1/7/19 7:52 PM, Andres Freund wrote:
> > Builtin functions for one, which we'd swatted down last time round due
> > to gperfs defficiencies.

Do you mean the fmgr table?

> >> But in any case, that sounds like a task for someone with
> >> more sense of Perl style than I have.
> > John, any chance you could help out with that... :)
>
> If he doesn't I will.

I'll take a crack at separating into a module.  I'll wait a bit in
case there are any stylistic suggestions on the patch as it stands.

Commits

  1. Use perfect hashing, instead of binary search, for keyword lookup.

  2. Reduce the size of the fmgr_builtin_oid_index[] array.

  3. Replace the data structure used for keyword lookup.