Re: databases limit
От | Fabio Angeluci Martins |
---|---|
Тема | Re: databases limit |
Дата | |
Msg-id | 200302061538.56890.famartins@gashost.com обсуждение исходный текст |
Ответ на | Re: databases limit (Andrew Sullivan <andrew@libertyrms.info>) |
Список | 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
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