Re: GiST index performance

Matthew Wakeling <matthew(at)flymine(dot)org> writes:
> So it seems that btree_gist and bioseg are not using that much CPU at all,
> compared to core postgres code. In fact, the majority of time seems to be
> spent in libc. Unfortunately my libc doesn't have any debugging symbols.

hmm ... memcpy or qsort maybe?

> Anyway, running opannotate seems to make it clear that time *is* spent in
> the gistnext function, but almost all of that is in children of the
> function. Lots of time is actually spent in fmgr_oldstyle though.

So it'd be worth converting your functions to V1 style.

> I'm guessing my next step is to install a version of libc with debugging
> symbols?

Yeah, if you want to find out what's happening in libc, that's what you
need.

regards, tom lane