Re: Binary search in fmgr_isbuiltin() is a bottleneck.

Andres Freund <andres@anarazel.de> writes:
> On 2017-09-28 18:52:28 -0400, Tom Lane wrote:
>> Uh, what?  Access to fmgr_nbuiltins shouldn't be part of any critical path
>> anymore after this change.

> Indeed. But the size of the the oid -> fmgr_builtins index array is
> relevant now. We could of course just make that dependent on
> FirstBootstrapObjectId, but that'd waste some memory.

Not enough to notice, considering there are pg_proc OIDs up in the 8K
range already.  We blow 2KB of never-accessed space for far less good
reason than this.

>> I'm kind of -0.5 on that.  I believe part of the argument for having
>> things set up as they were was to allow external code to access the
>> fmgr_builtins table (as my speed-test hack earlier today did).

> You could still do that, you'd just end up with a second copy. Doesn't
> seem bad for such an uncommon case.

If I understand what you're proposing, it would involve the extension
containing its *own* copy of the fmgr table, which seems pretty horrid.
It wouldn't necessarily match the actual contents in the core executable.

			regards, tom lane