Horton

Re: SendRowDescriptionMessage() is slow for queries with a lot of columns

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Michael Paquier <michael.paquier@gmail.com>
Cc: PostgreSQL mailing lists <pgsql-hackers@postgresql.org>, Tom Lane <tgl@sss.pgh.pa.us>
Date: 2017-09-29T21:17:42Z
Lists: pgsql-hackers 
On 2017-09-28 14:23:45 +0900, Michael Paquier wrote:
> On Thu, Sep 28, 2017 at 1:31 PM, Andres Freund <andres@anarazel.de> wrote:
> > On September 27, 2017 9:06:49 PM PDT, Andres Freund <andres@anarazel.de> wrote:
> >>On 2017-09-28 00:01:53 -0400, Tom Lane wrote:
> >>> Could we please not perpetuate the brain-dead "s" and "l" suffixes
> >>> on these names?  Given the lack of standardization as to how long
> >>> "long" is, that's entirely unhelpful.  I'd be fine with names like
> >>> pg_ntoh16/32/64 and pg_hton16/32/64.
> >>
> >>Yes. I'd polled a few people and they leaned towards those. But I'm
> >>perfectly happy to do that renaming.
> >
> > If somebody wants to argue for replacing hton/ntoh with {to,from}big or *be, now's the time.
> 
> OK. pg_hton16/32/64 and pg_ntoh16/32/64 are fine enough IMO.

Does anybody have an opinion on whether we'll want to convert examples
like testlibpq3.c (included in libpq.sgml) too? I'm inclined not to,
because currently using pg_bswap.h requires c.h presence (just for a few
typedefs and configure data).  There's also not really a pressing need.

Greetings,

Andres Freund

Commits

  1. Replace remaining uses of pq_sendint with pq_sendint{8,16,32}.

  2. Improve performance of SendRowDescriptionMessage.

  3. Use one stringbuffer for all rows printed in printtup.c.

  4. Add configure infrastructure to detect support for C99's restrict.

  5. Add more efficient functions to pqformat API.

  6. Allow to avoid NUL-byte management for stringinfos and use in format.c.

  7. Replace most usages of ntoh[ls] and hton[sl] with pg_bswap.h.

  8. Extend & revamp pg_bswap.h infrastructure.