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@xxxxxxxxxxxxxx [mailto:pgsql-general-owner@xxxxxxxxxxxxxx] On Behalf Of Bruce Momjian Sent: February 5, 2013 12:06 AM To: Merlin Moncure Cc: Carlo Stonebanks; kescobar@xxxxxxxxxxxxxxxxxx; pgsql-general@xxxxxxxxxxxxxx Subject: Re: 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 > <stonec.register@xxxxxxxxxxxx> 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 > > for functions that don t have SQL statements in them e.g. math and > > string processing. > > For cases involving data processing (SPI calls), C can be slower > because pl/pgsql has a lot of optimizations in it that can be very > easy to miss. I don't suggest writing backend C functions at all > unless you are trying to interface with a C library to access > 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? -- Bruce Momjian <bruce@xxxxxxxxxx> http://momjian.us EnterpriseDB http://enterprisedb.com + It's impossible for everything to be true. + -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
