2013/2/5 Bruce Momjian <bruce@xxxxxxxxxx>: > 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? PL/pgSQL can be faster than badly written C functions if there are bottle neck is in server side routines. Any well written C code will be faster then well written PL/pgSQL - how much depends on specific use case. If bottle neck is in IO op, then not too much - PL/pgSQL has not any specific optimization, that cannot be used in C. Regards Pavel > > -- > 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
