Re: Pipelined functions in Postgres

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(dot)amjad(at)gmail(dot)com]
Sent: Tuesday, September 19, 2006 11:08 PM
To: Milen Kulev
Cc: pgsql-performance(at)postgresql(dot)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(at)gmx(dot)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
<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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