Re: jsonpath

On Sun, Apr 21, 2019 at 2:01 AM Alexander Korotkov
<a(dot)korotkov(at)postgrespro(dot)ru> wrote:
>
> On Thu, Apr 18, 2019 at 4:09 AM John Naylor <john(dot)naylor(at)2ndquadrant(dot)com> wrote:
> > I was wondering about that. I measured the current size of
> > yy_transition to be 36492 on my machine. With the flag -Cfe, which
> > gives the smallest representation without backtracking, yy_nxt is 6336
> > (there is no yy_transition). I'd say that's a large enough difference
> > that we'd want the smaller representation if it makes little
> > difference in performance.
>
> Did I understand correctly that you've tried the same version of
> jsonpath_scan.l with different flex flags?

Correct.

> Did you also notice if
> changes 1d88a75c made to jsonpath_scan.l have singnificant influence?

Trying the same measurements above with backtracking put back in,
jsonpath_yylex was actually larger by a few hundred bytes, and there
was almost no difference in the transition/nxt tables.

--
John Naylor https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services