From: | Shridhar Daithankar <shridhar_daithankar(at)persistent(dot)co(dot)in> |
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To: | Seth Ladd <seth(at)picklematrix(dot)net> |
Cc: | pgsql-performance(at)postgresql(dot)org |
Subject: | Re: way to speed up a SELECT DISTINCT? |
Date: | 2003-10-10 11:00:30 |
Message-ID: | 3F86914E.2070100@persistent.co.in |
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Lists: | pgsql-performance |
Seth Ladd wrote:
>> peter(at)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
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