Re: Tsearch2 performance on big database

Mike Rylander wrote:
> On Tue, 22 Mar 2005 15:36:11 +0300 (MSK), Oleg Bartunov <oleg@sai.msu.su> wrote:
>>
>>use something like
>>echo "150000000" > /proc/sys/kernel/shmmax
>>to increase shared memory. In your case you could dedicate much more
>>memory.
>>
>>        Regards,
>>                Oleg


Thanks, I'll check that out.

> And Oleg should know.  Unless I'm mistaken, he (co)wrote tsearch2.
> Other than shared buffers, I can't imagine what could be causing that
> kind of slowness.  EXPLAIN ANALYZE, please?
>

ilab=# explain analyze select count(titel) from books where idxfti @@
to_tsquery('default', 'buckingham | palace');
                                                                QUERY PLAN

----------------------------------------------------------------------------------------------------------------------------------------
  Aggregate  (cost=35547.99..35547.99 rows=1 width=56) (actual
time=125968.119..125968.120 rows=1 loops=1)
    ->  Index Scan using idxfti_idx on books  (cost=0.00..35525.81
rows=8869 width=56) (actual time=0.394..125958.245 rows=3080 loops=1)
          Index Cond: (idxfti @@ '\'buckingham\' | \'palac\''::tsquery)
  Total runtime: 125968.212 ms
(4 rows)

Time: 125969.264 ms
ilab=#

 > As an example of what I think you *should* be seeing, I have a similar
 > box (4 procs, but that doesn't matter for one query) and I can search
 > a column with tens of millions of rows in around a second.
 >

That sounds very promising, I'd love to get those results.. could you
tell me what your settings are, howmuch memory you have and such? Thanks.

Rick


--
Systems Administrator for Rockingstone IT
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