From: Chris Hoover <revoohc@gmail.com>
To: Sriram Dandapani <sdandapani@counterpane.com>
Cc: pgsql-admin@postgresql.org
Subject: Re: autovacuum
Date: Thu, 1 Jun 2006 11:51:34 -0400
Message-ID: <1d219a6f0606010851r43d38bc1j2ab647e39bf7936e@mail.gmail.com> (raw)
In-Reply-To: <6992E470F12A444BB787B5C937B9D4DF04997AF3@ca-mail1.cis.local>
References: <6992E470F12A444BB787B5C937B9D4DF04997AF3@ca-mail1.cis.local>
Autovacuum does not release space back to the OS. It only marks the tuples
avaiable for reuse. To give the space back to the OS, you would have to run
a vacuum full on the table.
Chris
On 6/1/06, Sriram Dandapani <sdandapani@counterpane.com> wrote:
>
> Hi
>
>
>
> I have a table about 17G in size. I did a pg_relation_size before deleting
> 2 millions rows. I waited a few hours(actually overnight) and then checked
> the table size with pg_relation_size. The size reported was exactly the
> same.
>
>
>
> My autovacuum is set to run every 50 minutes.
>
>
>
> Settings:
>
>
>
> autovacuum = on # enable autovacuum subprocess?
>
> autovacuum_naptime = 3000 # time between autovacuum runs, in
> secs
>
> autovacuum_vacuum_threshold = 10000 # min # of tuple updates before
>
> # vacuum
>
> autovacuum_analyze_threshold = 1500 # min # of tuple updates before
>
> # analyze
>
> autovacuum_vacuum_scale_factor = 0.4 # fraction of rel size before
>
> # vacuum
>
> autovacuum_analyze_scale_factor = 0.2 # fraction of rel size before
>
> # analyze
>
> autovacuum_vacuum_cost_delay = -1
>
>
>
> vacuum_cost_delay = 200 # 0-1000 milliseconds
>
> #vacuum_cost_page_hit = 1 # 0-10000 credits
>
> #vacuum_cost_page_miss = 10 # 0-10000 credits
>
> #vacuum_cost_page_dirty = 20 # 0-10000 credits
>
> vacuum_cost_limit = 50
>
>
>
>
>
> work_mem = 802400 # min 64, size in KB
>
> maintenance_work_mem = 102400 # min 1024, size in KB
>
> #max_stack_depth = 2048 # min 100, size in KB
>
>
>
> # - Free Space Map -
>
> max_fsm_pages = 2000000
>
>
>
>
>
> Why doesn't pg_relation_size take the autovacuum maintenance into effect
>
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To: pgsql-admin@postgresql.org
Cc: revoohc@gmail.com, sdandapani@counterpane.com
Subject: Re: autovacuum
In-Reply-To: <1d219a6f0606010851r43d38bc1j2ab647e39bf7936e@mail.gmail.com>
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