| From: | Max Baker <max(at)warped(dot)org> |
|---|---|
| To: | PostgreSQL Performance Mailing List <pgsql-performance(at)postgresql(dot)org> |
| Subject: | speeding up COUNT and DISTINCT queries |
| Date: | 2003-03-12 22:38:11 |
| Message-ID: | 20030312223811.GM30411@warped.org |
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| Thread: | |
| Lists: | pgsql-performance |
I'm looking for a general method to
speed up DISTINCT and COUNT queries.
mydatabase=> EXPLAIN ANALYZE select distinct(mac) from node;
NOTICE: QUERY PLAN:
Unique (cost=110425.67..110514.57 rows=3556 width=6) (actual
time=45289.78..45598.62 rows=25334 loops=1)
-> Sort (cost=110425.67..110425.67 rows=35561 width=6) (actual
time=45289.77..45411.53 rows=34597 loops=1)
-> Seq Scan on node (cost=0.00..107737.61 rows=35561
width=6) (actual time=6.73..44383.57 rows=34597 loops=1)
Total runtime: 45673.19 msec
ouch.
I run VACCUUM ANALYZE once a day.
Thanks,
max
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