Re: What language is faster, C or PL/PgSQL?

If a C function was a call to multiple (unprepared) SQL statements, =
could PL/PGSQL's prepare-once plan caching have an advantage?


-----Original Message-----
From: pgsql-general-owner@postgresql.org =
[mailto:pgsql-general-owner@postgresql.org] On Behalf Of Bruce Momjian
Sent: February 5, 2013 12:06 AM
To: Merlin Moncure
Cc: Carlo Stonebanks; kescobar@estudiantes.uci.cu; =
pgsql-general@postgresql.org
Subject: Re: [GENERAL] What language is faster, C or PL/PgSQL?

On Mon, Feb  4, 2013 at 08:33:02AM -0600, Merlin Moncure wrote:
> On Sat, Feb 2, 2013 at 11:36 AM, Carlo Stonebanks=20
> <stonec.register@sympatico.ca> wrote:
> > Here is an advantage Plpgsql has:
> > http://www.postgresql.org/docs/9.1/static/plpgsql-expressions.html
> >
> > I guess you can offset this by creating your own prepared statements =
in C.
> > Otherwise, I can t think of how C could be slower. I would choose C=20
> > for functions that don t have SQL statements in them   e.g. math and =

> > string processing.
>=20
> For cases involving data processing (SPI calls), C can be slower=20
> because pl/pgsql has a lot of optimizations in it that can be very=20
> easy to miss.  I don't suggest writing backend C functions at all=20
> unless you are trying to interface with a C library to access=20
> functionality currently not exposed in SQL.

How is PL/pgSQL faster than C?  I thought we had optimized PL/pgSQL to =
save parsed functions, but I don't see how that would help with queries, =
which use SPI.  Am I missing something?

--=20
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + It's impossible for everything to be true. +


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