| From: | Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> |
|---|---|
| To: | Martijn van Oosterhout <kleptog(at)svana(dot)org> |
| Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Postgresql General <pgsql-general(at)postgresql(dot)org> |
| Subject: | Re: Idea for the statistics collector |
| Date: | 2002-06-21 12:23:47 |
| Message-ID: | 200206211223.g5LCNmj10034@candle.pha.pa.us |
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| Lists: | pgsql-general pgsql-hackers |
Martijn van Oosterhout wrote:
> Firstly, I was only thinking of going for the basic nodes (Index Scan, Seq
> Scan, Distinct). Other types have far more variables. Secondly, even if you
> only count, it's useful. For example, if it tells you that the planner is
> off by a factor of 10 more than 75% of the time, that's useful information
> independant of what the actual variables are.
Yes, only updating the stats if the estimate was off by a factor of 10
or so should cut down on the overhead.
--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
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