On Fri, 17 Oct 2014 13:12:27 -0400
Tom Lane <tgl@sss.pgh.pa.us> wrote:
> CK Tan <cktan@vitessedata.com> writes:
> > The bigint sum,avg,count case in the example you tried has some optimization. We use int128 to accumulate the
bigintinstead of numeric in pg. Hence the big speed up. Try the same query on int4 for the improvement where both pg
andvitessedb are using int4 in the execution.
>
> Well, that's pretty much cheating: it's too hard to disentangle what's
> coming from JIT vs what's coming from using a different accumulator
> datatype. If we wanted to depend on having int128 available we could
> get that speedup with a couple hours' work.
>
> But what exactly are you "compiling" here? I trust not the actual data
> accesses; that seems far too complicated to try to inline.
>
> regards, tom lane
>
>
I don't have any inside knowledge, but from the presentation given at the
recent SFPUG followed by a bit of google-fu I think these papers are
relevant:
http://www.vldb.org/pvldb/vol4/p539-neumann.pdf http://sites.computer.org/debull/A14mar/p3.pdf
-dg
--
David Gould 510 282 0869 daveg@sonic.net
If simplicity worked, the world would be overrun with insects.