Re: "Healing" a table after massive updates - Mailing list pgsql-general

From Scott Marlowe
Subject Re: "Healing" a table after massive updates
Date
Msg-id dcc563d10809110922i3ec99047p5f90262e3383b71a@mail.gmail.com
Whole thread Raw
In response to Re: "Healing" a table after massive updates  (Bill Moran <wmoran@collaborativefusion.com>)
Responses Re: "Healing" a table after massive updates  (Gregory Stark <stark@enterprisedb.com>)
List pgsql-general
On Thu, Sep 11, 2008 at 8:56 AM, Bill Moran
<wmoran@collaborativefusion.com> wrote:
> In response to Alvaro Herrera <alvherre@commandprompt.com>:
>
>> Bill Moran wrote:
>> > In response to "Gauthier, Dave" <dave.gauthier@intel.com>:
>> >
>> > > I might be able to answer my own question...
>> > >
>> > > vacuum FULL (analyze is optional)
>> >
>> > CLUSTER _may_ be a better choice, but carefully read the docs regarding
>> > it's drawbacks first.  You may want to do some benchmarks to see if it's
>> > really needed before you commit to it as a scheduled operation.
>>
>> What drawbacks?
>
> There's the whole "there will be two copies of the table on-disk" thing
> that could be an issue if it's a large table.

I've also found cluster to be pretty slow, even on 8.3.  On a server
that hits 30-40Megs a second write speed for random access during
pgbench, it's writing out at 1 to 2 megabytes a second when it runs,
and takes the better part of a day on our biggest table.  vacuumdb -fz
+ reindexdb ran in about 6 hours which means we could fit it into our
maintenance window.  vacuum moves a lot more data per second than
cluster.

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