Re: Pipelined functions in Postgres

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От Milen Kulev
Тема Re: Pipelined functions in Postgres
Дата
Msg-id 008b01c6dc32$a35c5290$0a00a8c0@trivadis.com
обсуждение исходный текст
Ответ на Re: Pipelined functions in Postgres  ("Talha Khan" <talha.amjad@gmail.com>)
Список pgsql-performance
Talha,
do you know how much memory is consumed by the SETOF function ?
What happens with memory consumption of the function if
SELECT ename FROM emp WHERE sal > $1
 returns 10 mio rows ? 
I suppose that memory for the RECORD structure is immediately reused by the next record.
 
Regards, Milen 
  
-----Original Message-----
From: Talha Khan [mailto:talha.amjad@gmail.com]
Sent: Tuesday, September 19, 2006 11:08 PM
To: Milen Kulev
Cc: pgsql-performance@postgresql.org
Subject: Re: [PERFORM] Pipelined functions in Postgres

Hi Milen,
 
Pipelined function is a code that acts like a database table.
 
Inorder to use this functionality in postgres you would need to write the function like this
 
CREATE OR REPLACE FUNCTION get_test_data (numeric)
    RETURNS SETOF RECORD AS
$$
DECLARE
    temp_rec    RECORD;
BEGIN
    FOR temp_rec IN (SELECT ename FROM emp WHERE sal > $1)
    LOOP
        RETURN NEXT temp_rec;
    END LOOP;
    RETURN;
END;
$$ LANGUAGE plpgsql;
 
now inorder to call this function you would write the code as follows
 
SELECT * FROM get_test_data(1000) AS t1 (emp_name VARCHAR);
 
 
Regards
Talha Amjad


 
On 9/19/06, Milen Kulev <makulev@gmx.net> wrote:
Hello Lister,
I am curios whether I can emulate the Oracle pipelined functions functionality in PG too (using RETURN NEXT ). For more
information and examples about Oracle pipelined functions see:
http://asktom.oracle.com/pls/ask/f?p=4950:8:8127757633768425921::NO::F4950_P8_DISPLAYID,F4950_P8_CRITERIA:4447489221109

I have used  pipeline functions in DWH enviromnent  with success and would like
To use similar concept in PG too.

Any help, examples , links and  shared experiences would be greately appreciated.

Best Regards.
Milen


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