| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Palle Girgensohn <girgen(at)pingpong(dot)net> |
| Cc: | John Hansen <john(at)geeknet(dot)com(dot)au>, pgsql-hackers(at)postgreSQL(dot)org |
| Subject: | Re: Bug? 8.0 does not use partial index |
| Date: | 2005-01-14 04:01:12 |
| Message-ID: | 19367.1105675272@sss.pgh.pa.us |
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| Lists: | pgsql-hackers |
Palle Girgensohn <girgen(at)pingpong(dot)net> writes:
>> No surprise. vacuum analyze produces an exact total row count, whereas
>> analyze can only produce an approximate total row count (since it only
>> samples the table rather than groveling over every row). Sometimes the
>> approximate count will be far enough off to affect the estimates.
> Reasonable. Thanks for clarifying that. In the normal case, vacuum analyze
> is better, I guess?
If you intend to do both steps, the combined command is definitely
better than issuing them separately. I wouldn't say that you need to
do the combined command in situations where you'd otherwise do just
one.
regards, tom lane
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