From: | "Lee Harr" <missive(at)hotmail(dot)com> |
---|---|
To: | pgsql-general(at)postgresql(dot)org |
Subject: | function calls in WHERE clause |
Date: | 2004-09-08 21:13:05 |
Message-ID: | BAY2-F19gcTEGi9R6K7000091a0@hotmail.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-general |
I have a view like this:
CREATE or replace VIEW program_member_this_year AS
SELECT DISTINCT person.person_id
FROM unit.person, unit.visit
WHERE
unit.person.person_id = unit.visit.person_id
AND
visit.program_id = this_program()
AND
visit.time_stamp > shared.last_september();
and I would like to speed it up ...
I notice that if I write it like this:
CREATE or replace VIEW program_member_this_year AS
SELECT DISTINCT person.person_id
FROM unit.person, unit.visit
WHERE
unit.person.person_id = unit.visit.person_id
AND
visit.program_id = 3
AND
visit.time_stamp > '2004-9-1';
It takes about 1/4 the time as with the function calls.
Both of those function calls will always return the exact
same thing for any given query.
My approach now is to make a Pl/PgSQL function which
will build up the correct query with the function calls
replaced by their constant results .... but is there a
better way?
I should note that this_program() is defined as VOLATILE.
It was a while ago, but I believe this is because I have
a this_program() defined in each schema and they
return a different value depending on which schema
you are in when you call the function...
Thanks for any insight.
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Next Message | Tom Lane | 2004-09-08 21:42:12 | Re: function calls in WHERE clause |
Previous Message | Karl O. Pinc | 2004-09-08 21:10:45 | Re: Returning multiple values (but one row) in plpgsql |