| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | dforum <dforums(at)vieonet(dot)com> |
| Cc: | Matthew Wakeling <matthew(at)flymine(dot)org>, pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: GiST index performance |
| Date: | 2009-04-16 17:52:35 |
| Message-ID: | 26037.1239904355@sss.pgh.pa.us |
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| Lists: | pgsql-performance |
dforum <dforums(at)vieonet(dot)com> writes:
> If you analyse query plan, you see that most of the time are lost during
> sequencial scan, and you have 2 seq scan.
I think you missed the loops count.
>> -> Index Scan using location_object_start_gist on location l1
>> (cost=0.00..4.16 rows=150 width=65)
>> (actual time=3.354..10.757 rows=3 loops=211880)
>> Index Cond: ((l1.objectid = l2.objectid) AND
>> (l2.intermine_start <= l1.intermine_start) AND (l2.intermine_end >=
>> l1.intermine_start))
This indexscan is accounting for 10.757 * 211880 msec, which is 99%
of the runtime.
regards, tom lane
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