Re: Vacuum questions...

Hannu Krosing wrote:

>On L, 2005-09-24 at 20:25 -0700, Joshua D. Drake wrote:
>
>  
>
>>Actually this also probably would not gain you much in 8.1
>>as vacuum in theory is already dealing with itself.
>>    
>>
>
>Interesting. Could you explain it in a more detailed way ?
>How does vacuum "deal with itself" in 8.1 ?
>  
>
Autovacuum is integrated into the backend for 8.1

>Not sure of a "quick scan" approach, espacially for tables big enough
>for the progress info would be interesting (in my experience a scan is
>never quick).
>  
>
It would be a seq so on a larger table it would probably be
a long time. I was thinking if there was some mapping of
known dead rows or something so we didn't have to scan
the page for the statistics.

We of course would scan to do the actual work but if vacuum
cleared the map while doing the work it may not be that bad.

Sincerely,

Joshua D. Drake


>Perhaps VACUUM could send some statistics after each N pages and this
>would then be available through something similar to pg_statistics
>table.
>
>  
>


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