| From: | "Thurber, Fred" <Fred(dot)Thurber(at)gdit(dot)com> |
|---|---|
| To: | "pgsql-novice(at)postgresql(dot)org" <pgsql-novice(at)postgresql(dot)org> |
| Subject: | Understanding the output of EXPLAIN ANALYSE |
| Date: | 2009-07-23 17:14:54 |
| Message-ID: | 42FD6908B3553343B8957500E798AABD19B4D93F03@EXCHCCR04.ad.local |
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| Thread: | |
| Lists: | pgsql-novice |
I am a newbie to PostgreSQL and am a little confused by the execution plan of a query we are working. The SQL does some joins and the resulting plan looked like this:
"Nested Loop (cost=78.63..101.14 rows=1 width=256) (actual time=0.000..16.000 rows=2818 loops=1)"
...
"Total runtime: 16.000 ms"
So the cost was 101. We put indexes on the two tables that were being joined and re-ran EXPLAIN ANALYZE. The cost went way down, but the execution time went way up. What am I missing?
"Nested Loop (cost=0.00..15.28 rows=1 width=256) (actual time=0.000..110.000 rows=2818 loops=1)"
...
"Total runtime: 110.000 ms"
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