Thread: What language is faster, C or PL/PgSQL?
<font face="Times New Roman">Hi people,<br /><br /> I need to write an algorithm for processing large amounts of data. Iwant to write a function on PgAdmin 3 to solve my problem. I need to know what language should be used, C or PL/PgSQL? <br/><br /> Needless to say, what I need is quickly. What language is faster, </font><font face="Times New Roman"><font face="TimesNew Roman">C or PL/PgSQL</font>? <br /></font><div class="moz-signature"><br /><div style="font: 16px Times NewRoman;color: black"> Greetings, Karel Riverón<br /> University of Informatics Science <br /><br /><br /></div></div>
On Sat, Feb 2, 2013 at 10:42 AM, Karel River=C3=B3n Escobar < kescobar@estudiantes.uci.cu> wrote: > Hi people, > > I need to write an algorithm for processing large amounts of data. I want > to write a function on PgAdmin 3 to solve my problem. I need to know what > language should be used, C or PL/PgSQL? > > Needless to say, what I need is quickly. What language is faster, C or > PL/PgSQL? > Hello, performance processing data is not 100% related to language, IMO is more related with algorithm. You need to check your algorithm and order. Answering your question i suggest you C could be some ugly but will be faster, in this point could be good read an opinion from any PG hacker. Regards, > > Greetings, Karel River=C3=B3n > University of Informatics Science > > > --=20 Cristian Salamea @ovnicraft
Here is an advantage Plpgsql has: http://www.postgresql.org/docs/9.1/static/plpgsql-expressions.html =20 I guess you can offset this by creating your own prepared statements in = C. Otherwise, I can=92t think of how C could be slower. I would choose C = for functions that don=92t have SQL statements in them =96 e.g. math and = string processing.=20 =20 From: pgsql-general-owner@postgresql.org [mailto:pgsql-general-owner@postgresql.org] On Behalf Of Karel River=F3n Escobar Sent: February 2, 2013 10:42 AM To: pgsql-general@postgresql.org Subject: [GENERAL] What language is faster, C or PL/PgSQL? =20 Hi people, I need to write an algorithm for processing large amounts of data. I = want to write a function on PgAdmin 3 to solve my problem. I need to know what language should be used, C or PL/PgSQL?=20 Needless to say, what I need is quickly. What language is faster, C or PL/PgSQL?=20 =20 Greetings, Karel River=F3n University of Informatics Science=20
On Sat, Feb 2, 2013 at 11:36 AM, Carlo Stonebanks <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=92t think of how C could be slower. I would choose C for > functions that don=92t have SQL statements in them =96 e.g. math and stri= ng > 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. merlin
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@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 canât think of how C could be slower. I would choose C for > > functions that donât have SQL statements in them â 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@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + It's impossible for everything to be true. +
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. + -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To = make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
2013/2/5 Bruce Momjian <bruce@momjian.us>: > 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@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 i= n C. >> > Otherwise, I can=E2=80=99t think of how C could be slower. I would cho= ose C for >> > functions that don=E2=80=99t have SQL statements in them =E2=80=93 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@momjian.us> http://momjian.us > EnterpriseDB http://enterprisedb.com > > + It's impossible for everything to be true. + > > > -- > Sent via pgsql-general mailing list (pgsql-general@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-general