Re: Inlining comparators as a performance optimisation

On Wed, Sep 21, 2011 at 4:46 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>  As such, they could not have entries in pg_proc, so
> it seems like there's no ready way to represent them in the catalogs.

Why couldn't they be in pg_proc with a bunch of opaque arguments like
the GIST opclass support functions?

I'm a bit puzzled what the arguments would look like. They would still
need to know the collation, nulls first/last flags, etc.
And calling it would still not be inlinable.  So they would have to
check those flags on each invocation instead of having a piece of
straightline code that hard codes the behaviour with the right
behaviour inline.  ISTM the hope for a speedup from the inlining
mostly came from the idea that the compiler might be able to hoist
this logic outside the loop (and I suppose implement n specialized
loops depending on the behaviour needed).

--
greg