Thread: AGREGATE FUNCTIONS
Hello, I would like to know where in the source-code of postgres is
located the code of the aggregate functions min, max, avg.
I wish to develop more statistical aggregate functions, and I prefer to
use C than to write then in the PL/R.
Thanks
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On Tue, 6 Jun 2006, Roberto Rezende de Assis wrote: > Hello, I would like to know where in the source-code of postgres is located > the code of the aggregate functions min, max, avg. They're in src/backend/utils/adt/numeric.c > I wish to develop more statistical aggregate functions, and I prefer to use C > than to write then in the PL/R. Make sure you read section "32.10 User-Defined aggregates" in the manual: http://www.postgresql.org/docs/current/interactive/xaggr.html Also, take a look at contrib/intagg for another example. - Heikki
Roberto Rezende de Assis wrote: > Hello, I would like to know where in the source-code of postgres is > located the code of the aggregate functions min, max, avg. > I wish to develop more statistical aggregate functions, and I prefer to > use C than to write then in the PL/R. http://projects.commandprompt.com/public/pgsql/browser/trunk/pgsql/src/backend/utils/adt http://projects.commandprompt.com/public/pgsql/browser/trunk/pgsql/src/backend/utils/adt/numeric.c http://projects.commandprompt.com/public/pgsql/browser/trunk/pgsql/src/backend/utils/adt That will give you and easy interface to view the code and everything after browser is the CVS source tree so you can look for yourself within your copy of HEAD or 8.1 or whatever. Sincerely, Joshua D. Drake > > Thanks > > > > _______________________________________________________ Navegue com o > Yahoo! Acesso Grátis, assista aos jogos do Brasil na Copa e ganhe > prêmios de hora em hora! http://br.yahoo.com/artilheirodacopa/ > > ---------------------------(end of broadcast)--------------------------- > TIP 9: In versions below 8.0, the planner will ignore your desire to > choose an index scan if your joining column's datatypes do not > match > -- === The PostgreSQL Company: Command Prompt, Inc. === Sales/Support: +1.503.667.4564 || 24x7/Emergency: +1.800.492.2240 Providing the most comprehensive PostgreSQL solutionssince 1997 http://www.commandprompt.com/
> Hello, I would like to know where in the source-code of postgres is > located the code of the aggregate functions min, max, avg. > I wish to develop more statistical aggregate functions, and I prefer to > use C than to write then in the PL/R. There is a library in "contrib" called "intagg." I wrote it a few years ago, and I have to laugh at the README file because I must have been stoned or something, because I can't understand it. Anyways, if you want to make an aggregate function, it covers what you need. Feel free to ignore the array stuff, because you probably won't need to deal with it. Aggregates have basically two functions, a single function called on every iteration of the "query" (or GROUP BY) for "state." Then there is a function that is called at the end called "final." The PostgreSQL docs are pretty good as well.