Re: Doubt w.r.t vacuum - Mailing list pgsql-hackers

From Doug McNaught
Subject Re: Doubt w.r.t vacuum
Date
Msg-id m31xware3d.fsf@varsoon.wireboard.com
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In response to Doubt w.r.t vacuum  ("Shridhar Daithankar" <shridhar_daithankar@persistent.co.in>)
Responses Re: Doubt w.r.t vacuum  ("Shridhar Daithankar" <shridhar_daithankar@persistent.co.in>)
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"Shridhar Daithankar" <shridhar_daithankar@persistent.co.in> writes:

> Hi,
> 
> I was just wondering over it. This is for difference between vacuum full and 
> vacuum analyze. Can somebody enlighten,
> 
> 1. IIRC vacuum recovers/reuses dead tuples generated from update but can not do 
> so for delete? Why?

YDNRC.

> 2. Vacuum full locks entire table, is it possible that it locks a
> page at a time and deal with it. It will make vacuum full
> non-blocking at the cost of letting it run for a longer time. Or is
> it that the defragmentation algorithm needs more than a page?

This I don't know, but I imagine that if what you suggest was easy to
do it would have been done, and there would have been no need for two
different kinds of VACUUM.

-DOUG


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