Re: Auto Vacuum question?

On 6 4 , 10 49 , alvhe(dot)(dot)(dot)(at)commandprompt(dot)com (Alvaro Herrera) wrote:
> Charles.Hou wrote:
> > i set the auto vacuum option to enable. but my database size(hard-
> > disk
> > space) still increased from 420MB to 440MB in 8 hours. most of the
> > operations in this database are the "Select" query command, just few
> > of "Update or Insert".
> > why it can be increased so strongly?
> > after i executed the command " vaccumdb -f -z testdb", but the size
> > just decreased 1 or 2MB...
> > what's the problem?
>
> 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.
>
> Have you done both?
>
> --
> Alvaro Herrera http://www.CommandPrompt.com/
> The PostgreSQL Company - Command Prompt, Inc.
>
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it's my postgresql.conf

autovacuum = on # enable autovacuum
subprocess?
autovacuum_naptime = 20 # time between autovacuum
runs, in secs
autovacuum_vacuum_threshold = 1 # min # of tuple updates
before
autovacuum_analyze_threshold = 1 # min # of tuple updates
before
autovacuum_vacuum_scale_factor = 1 # fraction of rel size before
autovacuum_analyze_scale_factor = 1 # fraction of rel size before

#autovacuum_vacuum_cost_delay = -1 # default vacuum cost delay
for
#autovacuum_vacuum_cost_limit = -1 # default vacuum cost limit
for