I'd recommend our contrib/pg_trgm module, which provides
trigram based fuzzy search and return results ordered by similarity
to your query.  Read 
for more details.

On Sun, 29 May 2005, Michael Engelhart wrote:

Hi -

I have a table of about 3 million rows of city "aliases" that I need to query using LIKE - for example:

select * from city_alias where city_name like '%FRANCISCO'

When I do an EXPLAIN ANALYZE on the above query, the result is:

Seq Scan on city_alias (cost=0.00..59282.31 rows=2 width=42) (actual time=73.369..3330.281 rows=407 loops=1)
  Filter: ((name)::text ~~ '%FRANCISCO'::text)
Total runtime: 3330.524 ms
(3 rows)

this is a query that our system needs to do a LOT. Is there any way to improve the performance on this either with changes to our query or by configuring the database deployment? We have an index on city_name but when using the % operator on the front of the query string postgresql can't use the index .

Thanks for any help.


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