On Wednesday 26 November 2003 18:39, Roger Ging wrote:
> version 7.4 results:
> explain analyse SELECT L.row_id FROM music.logfile L LEFT JOIN
> music.program P ON
> music.fn_mri_id_no_program(P.mri_id_no) = L.program_id
> WHERE  L.station = UPPER('kabc')::VARCHAR
> AND L.air_date = '04/12/2002'::TIMESTAMP
> AND P.cutoff_date IS NULL
> ORDER BY L.chron_start,L.chron_end;

>                 ->  Seq Scan on program p  (cost=0.00..15192.35
> rows=4335 width=20) (actual time=109.045..1955.882 rows=173998 loops=1)

The estimated number of rows here (4335) is *way* off (173998 actually). If 
you only had 4335 rows, then this might be a more sensible plan.

First step is to run:
Then, check the definition of your function fn_mri_id_no_program() and make 
sure it is marked immutable/stable (depending on what it does) and that it's 
returning a varchar.

  Richard Huxton
  Archonet Ltd

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