Re: GiST index performance

From: Tom Lane
Subject: Re: GiST index performance
Date: ,
Msg-id: 24123.1244734792@sss.pgh.pa.us
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In response to: Re: GiST index performance  (Matthew Wakeling)
Responses: Re: GiST index performance  (Matthew Wakeling)
Re: GiST index performance  (Heikki Linnakangas)
List: pgsql-performance

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GiST index performance  (Matthew Wakeling, )
 Re: GiST index performance  (Robert Haas, )
  Re: GiST index performance  (Matthew Wakeling, )
   Re: GiST index performance  (Tom Lane, )
    Re: GiST index performance  (Matthew Wakeling, )
     Re: GiST index performance  (Tom Lane, )
      Re: GiST index performance  (Matthew Wakeling, )
       Re: GiST index performance  (Tom Lane, )
        Re: GiST index performance  (Matthew Wakeling, )
         Re: GiST index performance  (Matthew Wakeling, )
          Re: GiST index performance  (Matthew Wakeling, )
           Re: GiST index performance  (Tom Lane, )
           Re: GiST index performance  (Adam Gundy, )
        Re: GiST index performance  (Heikki Linnakangas, )
      Re: GiST index performance  (Greg Smith, )
       Re: GiST index performance  (Robert Haas, )
 Re: GiST index performance  (Bruce Momjian, )
  Re: GiST index performance  (Robert Haas, )
  Re: GiST index performance  (Matthew Wakeling, )
   Re: GiST index performance  (Robert Haas, )
   Re: GiST index performance  (Yeb Havinga, )
    Re: GiST index performance  (Yeb Havinga, )
     Re: GiST index performance  (Yeb Havinga, )
      Re: GiST index performance  (Yeb Havinga, )
       Re: GiST index performance  (Yeb Havinga, )
        Re: GiST index performance  (Kenneth Marshall, )
         Re: GiST index performance  (Yeb Havinga, )
          Re: GiST index performance  (Matthew Wakeling, )
           Re: GiST index performance  (Yeb Havinga, )
            Re: GiST index performance  (Matthew Wakeling, )

Matthew Wakeling <> 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


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