Re: Why vacuum? - Mailing list pgsql-hackers

From Daniele Orlandi
Subject Re: Why vacuum?
Date
Msg-id 3A3919BD.3CF14B9F@orlandi.com
Whole thread Raw
In response to AW: Why vacuum?  (Zeugswetter Andreas SB <ZeugswetterA@wien.spardat.at>)
List pgsql-hackers
Alfred Perlstein wrote:
> 
> If you're talking about vacuum, you really don't want to do this,

No, I'm not talking about vacuum as it is intended now, it's only a
process that scans tables to find available blocks/tuples. It is
virtually optional, if it doesn't run, the database will behave just
like now.

> what's going to happen is that since you have an exclusive lock on
> the file during your vacuum and no way to do priority lending you
> can deadlock.

No exclusive lock, it's just a reader.

> When your table grows to be very large you'll see what we're talking
> about.

I see this as an optimization issue. If the scanner isn't smart and
loses time scanning areas of the table that have not been emptied, you
go back to the current behaviour.

Bye!


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