Date: Thu, 26 Oct 2006 14:19:18 -0500
From: "Jim C. Nasby" <jim@nasby.net>
To: Matthew Peters <matthew@haydrian.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, pgsql-performance@postgresql.org
Subject: Re: Stored procedure slower than sql?
Message-ID: <20061026191918.GE26892@nasby.net>
References: <21413.1161879278@sss.pgh.pa.us>
	<775F825B46B551499DC75DC4E92F80AB564D05@jupiter.ad.haydrian.com>
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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
> 
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-- 
Jim Nasby                                            jim@nasby.net
EnterpriseDB      http://enterprisedb.com      512.569.9461 (cell)