Re: databases limit - Mailing list pgsql-general

Tks very much for the help andrew, tom
i'm still waiting the response in the hackers list too ...

On Thursday 06 February 2003 14:15, you wrote:
> On Thu, Feb 06, 2003 at 12:30:03AM -0500, Tom Lane wrote:
> > I have a feeling that what the questioner really means is "how can I
> > limit the resources consumed by any one database user?"  In which case
>
> (I'm moving this to -hackers 'cause I think it likely belongs there.)
>
> I note that this question has come up before, and several people have
> been sceptical of its utility.  In particular, in this thread
>
> <http://groups.google.ca/groups?hl=en&lr=&ie=UTF-8&threadm=Pine.LNX.4.21.02
>12221510560.15719-100000%40linuxworld.com.au&rnum=1&prev=/groups%3Fq%3Dlimit
>%2Bresources%2B%2Bgroup:comp.databases.postgresql.*%26hl%3Den%26lr%3D%26ie%3
>DUTF-8%26selm%3DPine.LNX.4.21.0212221510560.15719-100000%2540linuxworld.com.
>au%26rnum%3D1>
>
> (sorry about the long line: I just get errors searching at the official
> archives) Tom Lane notes that you could just run another back end to
> make things more secure.
>
> That much is true; but I'm wondering whether it might be worth it to
> limit how much a _database_ can use.  For instance, suppose I have a
> number of databases which are likely to see sporadic heavy loads.
> There are limitations on how slow the response can be.  So I have to
> do some work to guarantee that, for instance, certain tables from
> each database don't get flushed from the buffers.
>
> I can do this now by setting up separate postmasters.  That way, each
> gets its own shared memory segment.  Those "certain tables" will be
> ones that are frequently accessed, and so they'll always remain in
> the buffer, even if the other database is busy (because the two
> databases don't share a buffer).  (I'm imagining the case -- not
> totally imaginary -- where one of the databases tends to be accessed
> heavily during one part of a 24 hour day, and another database gets
> hit more on another part of the same day.)
>
> The problem with this scenario is that it makes administration
> somewhat awkward as soon as you have to do this 5 or 6 times.  I was
> thinking that it might be nice to be able to limit how much of the
> total resources a given database can consume.  If one database were
> really busy, that would not mean that other databases would
> automatically be more sluggish, because they would still have some
> guaranteed minimum percentage of the total resources.
>
> So, anyone care to speculate?

--
Fabio Angeluci Martins
famartins at gashost com
www.gashost.com
UIN: 24397990