Re: Auto Vacuum question? - Mailing list pgsql-admin

From Alvaro Herrera
Subject Re: Auto Vacuum question?
Date
Msg-id 20070605124712.GA3859@alvh.no-ip.org
Whole thread Raw
In response to Re: Auto Vacuum question?  ("Charles.Hou" <ivan.hou@msa.hinet.net>)
List pgsql-admin
Charles.Hou wrote:
> On 6 4 ,   10 49 , alvhe...@commandprompt.com (Alvaro Herrera) wrote:

> > It is normal that the tables grow a bit to a stationary state of dead
> > space (generated by UPDATE and DELETE).  However it is not normal if it
> > loses track of that dead space.  One thing you can and should do is
> > adjust the autovacuum settings (for example lowering the vacuum scale
> > factor and threshold values).  Another is to correctly set the FSM
> > values.

> autovacuum_vacuum_scale_factor = 1      # fraction of rel size before
> autovacuum_analyze_scale_factor = 1     # fraction of rel size before

These values are rather strange; they mean it would wait until the table
is populated by as many dead tuples as there are live tuples, before
vacuuming it.  This is probably too much.  Try decreasing the vacuum
scale factor to 0.2 or maybe 0.1 and see how it goes.

--
Alvaro Herrera                 http://www.amazon.com/gp/registry/DXLWNGRJD34J
"La fuerza no está en los medios físicos
sino que reside en una voluntad indomable" (Gandhi)

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