| From: | Martijn van Oosterhout <kleptog(at)svana(dot)org> |
|---|---|
| To: | TJ O'Donnell <tjo(at)acm(dot)org> |
| Cc: | pgsql-general(at)postgresql(dot)org, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, lists(at)boutiquenumerique(dot)com |
| Subject: | Re: Does indexing help >= as well as = for integer columns? |
| Date: | 2005-02-02 15:29:24 |
| Message-ID: | 20050202152923.GG18657@svana.org |
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| Lists: | pgsql-general |
On Wed, Feb 02, 2005 at 06:51:13AM -0800, TJ O'Donnell wrote:
> I had thought that the Creation of the Index would do something
> equivalent to Analyze. I tried Analyze Verbose and it improved
> the scanner's ability to predict when an index would be useful.
Create index creates an index, analyze collects statistics. Neither
happens without being asked for...
> Last week, I asked about visualizing B-tree "coverage". I think
> I meant "Can I see the histograms that Analyze creates?"
> Are they available anywhere? The docs mention them (bins) and I
> was hoping Analyze Verbose would show them to me.
Maybe pg_statistic? You may need the oid of the column definition to
work out what goes where...
Hope this helps,
--
Martijn van Oosterhout <kleptog(at)svana(dot)org> http://svana.org/kleptog/
> Patent. n. Genius is 5% inspiration and 95% perspiration. A patent is a
> tool for doing 5% of the work and then sitting around waiting for someone
> else to do the other 95% so you can sue them.
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