Re: way to speed up a SELECT DISTINCT? - Mailing list pgsql-performance

Seth Ladd wrote:

>> peter@bernardo:express=# explain select distinct region from region;
>>                                           QUERY PLAN
>> -----------------------------------------------------------------------
>> -----------------------
>>  Unique  (cost=0.00..4326.95 rows=9518 width=14)
>>    ->  Index Scan using regionview_region on region   (cost=0.00..4089.00
>> rows=95183 width=14)
>> (2 rows)
>
>
> Thanks for the tip, I'll give this a shot soon.  I am curious, your
> example above does not use GROUP BY yet you have an INDEX SCAN.  I am
> using a similar query, yet I get a full table scan.  I wonder how they
> are different?

Have you tuned your shared buffers and effective cache correctly?

  Shridhar