Обсуждение: RE: vacuum

Maybe a good measure of how often the database needs to be vacuumed is how
often the administrators currently vacuum it?

For instance, if it's being vacuumed less than once a day, it may be
perfectly acceptable to vacuum it once early in the morning when nobody is
using it - assuming nobody uses it then, of course.

If the administrators have been using the product for a while, it may not be
too much of a problem to ask when the "slow times" are - you might be able
to just ask them.  We do electronic billing, and I've found that the people
who know the most about slow times and such are those people, and the Tech
Support Queen.

Just a couple of thoughts...
Neil

-----Original Message-----
From: Rainer Mager [mailto:rmager@vgkk.com]
Sent: Thursday, July 13, 2000 5:47 PM
To: pgsql-admin@postgresql.org
Subject: [ADMIN] vacuum


Hi all,

    I'm sure many other people have faced this and I'm wondering what
solutions
were found.

    We have a product that uses PostgreSQL as its database. Currently,
via a
web-based administration interface, we provide the administrators the
ability to vacuum their database whenever they wish to. We would prefer to
provide this functionality automatically such that they don't need to think
about it.
    We could easily have the system vacuum once a day (or week or
whatever) but
we are concerned that the vacuum process will slow down the system while it
is being performed. This means that we would need to try to do some analysis
on the business of the system and then vacuum at a perceived slow time. This
sounds difficult.
    What do other people do? How much of a hit is vacuum when the system
is
operating? Any other ideas?


Thanks in advance,

--Rainer

Good ideas except I think I wasn't clear. The system is a commercial product
with numerous individual customers. Each customer is somewhat unique and we
want to have the system capable of vacuuming automatically for all users.

The thing is that some users might have systems that are used little in the
early morning but others might be very different. We would rather not do
usage statistic gathering/analysis if there was a better way.

-Rainer


> -----Original Message-----
> From: pgsql-admin-owner@hub.org
> [mailto:pgsql-admin-owner@hub.org]On Behalf Of Neil Toronto
> Sent: Friday, July 14, 2000 8:48 AM
> To: pgsql-admin@postgresql.org
> Subject: RE: [ADMIN] vacuum
>
>
> Maybe a good measure of how often the database needs to be vacuumed is how
> often the administrators currently vacuum it?
>
> For instance, if it's being vacuumed less than once a day, it may be
> perfectly acceptable to vacuum it once early in the morning when nobody is
> using it - assuming nobody uses it then, of course.
>
> If the administrators have been using the product for a while, it
> may not be
> too much of a problem to ask when the "slow times" are - you might be able
> to just ask them.  We do electronic billing, and I've found that
> the people
> who know the most about slow times and such are those people, and the Tech
> Support Queen.
>
> Just a couple of thoughts...
> Neil

Bonjour Rainer Mager
>
> Good ideas except I think I wasn't clear. The system is a commercial product
> with numerous individual customers. Each customer is somewhat unique and we
> want to have the system capable of vacuuming automatically for all users.
>
> The thing is that some users might have systems that are used little in the
> early morning but others might be very different. We would rather not do
> usage statistic gathering/analysis if there was a better way.

    We have the same kind of application here.
    We vacuum according the load, if the load start to be "high"
    we vacuum ->earlier<-, ok there is a little penalty on users, but as soon
    the data-base is clean, the performance is dramaticaly improving
    and the load just drop. So instead to have user penalised
    for a long time, we just use it as a trigger to clean the base.
    (we do not want the user to vacuum at will)

A bientot
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