The planner has no idea what $1 and $2 are when it plans the query, so
that could easily explain why the performance is different. You can
prepare statements in psql (at least in 8.1), which would be a good way
to verify that theory (compare EXPLAIN for prepared vs. non).
On Thu, Oct 26, 2006 at 09:21:37AM -0700, Matthew Peters wrote:
> Parameterized.
>
> IE (very simplified)
>
> CREATE OR REPLACE FUNCTION my_function(IN param1 BIGINT, IN param2
> INTEGER)
> RETURNS my_type
> SECURITY DEFINER
> AS
> $$
> /* my_type = (a,b,c) */
> Select a,b,c
> FROM my_table
> WHERE indexed_column = $1
> AND partition_constraint_column = $2;
> $$
> LANGUAGE SQL;
>
>
>
>
> Matthew A. Peters
> Sr. Software Engineer, Haydrian Corp.
> matthew@haydrian.com
> (mobile) 425-941-6566
> Haydrian Corp.
> -----Original Message-----
> From: Tom Lane [mailto:tgl@sss.pgh.pa.us]
> Sent: Thursday, October 26, 2006 9:15 AM
> To: Matthew Peters
> Cc: pgsql-performance@postgresql.org
> Subject: Re: [PERFORM] Stored procedure slower than sql?
> Importance: High
>
> "Matthew Peters" <matthew@haydrian.com> writes:
> > How can a stored procedure containing a single query not implement the
> > same execution plan (assumption based on the dramatic performance
> > difference) that an identical ad-hoc query generates?
>
> Parameterized vs non parameterized query?
>
> regards, tom lane
>
> ---------------------------(end of broadcast)---------------------------
> TIP 1: if posting/reading through Usenet, please send an appropriate
> subscribe-nomail command to majordomo@postgresql.org so that your
> message can get through to the mailing list cleanly
>
--
Jim Nasby jim@nasby.net
EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)