| From: | Alexander Korotkov <a(dot)korotkov(at)postgrespro(dot)ru> |
|---|---|
| To: | John Naylor <john(dot)naylor(at)2ndquadrant(dot)com> |
| Cc: | Andres Freund <andres(at)anarazel(dot)de>, Nikita Glukhov <n(dot)gluhov(at)postgrespro(dot)ru>, Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com>, Oleg Bartunov <obartunov(at)postgrespro(dot)ru>, Michael Paquier <michael(at)paquier(dot)xyz>, Stas Kelvich <s(dot)kelvich(at)postgrespro(dot)ru>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>, Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com>, David Steele <david(at)pgmasters(dot)net>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Andrew Dunstan <andrew(dot)dunstan(at)2ndquadrant(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> |
| Subject: | Re: jsonpath |
| Date: | 2019-03-19 10:43:12 |
| Message-ID: | CAPpHfdsM86wA4_e4osPcPTJ8vMRDGZC-=DNPGxDuQMDrOs=GGg@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Tue, Mar 19, 2019 at 12:23 PM John Naylor
<john(dot)naylor(at)2ndquadrant(dot)com> wrote:
> On Sun, Feb 24, 2019 at 5:03 PM Alexander Korotkov
> <a(dot)korotkov(at)postgrespro(dot)ru> wrote:
> > On Wed, Jan 30, 2019 at 5:28 AM Andres Freund <andres(at)anarazel(dot)de> wrote:
> > > Why -CF, and why is -p repeated?
> >
> > BTW, for our SQL grammar we have
> >
> > > scan.c: FLEXFLAGS = -CF -p -p
> >
> > Is it kind of default?
>
> I just saw this in the committed patch. This is not default, it's
> chosen for maximum performance at the expense of binary/memory size.
> That's fine, but with a little effort you can also make the scanner
> non-backtracking for additional performance, as in the attached.
We're working on patchset improving flex scanner. Already have
similar change among the others. But thanks a lot for your attention!
------
Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company
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