Re: Trigram is slow when 10m rows

I have a simple table with Trigram index,

create table mytable(hash char(40), title text);
create index title_trgm_idx on mytable using gin(title gin_trgm_ops);

When I run a query with 10m rows, it uses the Trigram index, but takes
3s to execute, very slow.
(I have 80m rows, but only inserted 10m for testing purpose)

test=# select count(*) from mytable;
  count
----------
 13971887
(1 row)

test=# explain analyze select * from mytable where title ilike 'x264';
                                                              QUERY PLAN
--------------------------------------------------------------------------------------------------------------------------------------
 Bitmap Heap Scan on mytable  (cost=462.69..5639.67 rows=1380
width=83) (actual time=2937.308..2937.308 rows=0 loops=1)
   Recheck Cond: (title ~~* 'x264'::text)
   Rows Removed by Index Recheck: 11402855
   Heap Blocks: exact=39557 lossy=158010
   ->  Bitmap Index Scan on title_trgm_idx  (cost=0.00..462.35
rows=1380 width=0) (actual time=342.440..342.440 rows=1220793 loops=1)
         Index Cond: (title ~~* 'x264'::text)
 Planning time: 0.611 ms
 Execution time: 2937.729 ms
(8 rows)

Any ideas to speed things up?

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Best Regards,
Aaron Lewis - PGP: 0x13714D33 - http://pgp.mit.edu/
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