Re: Hope for a new PostgreSQL era?
От | Eduardo Morras |
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Тема | Re: Hope for a new PostgreSQL era? |
Дата | |
Msg-id | 4EE225850003E2F9@ обсуждение исходный текст |
Ответ на | Re: Hope for a new PostgreSQL era? (Craig Ringer <ringerc@ringerc.id.au>) |
Список | pgsql-general |
Sorry for delay, >>I wonder if the prioritisation could be done=20 >>using nice - each backend is a separate=20 >>process, so why not to do 'nice(10)' for low=20 >>priority processes or something like that. > >Yes, to a limited degree you can prioritise=20 >queries using nice and ionice, but it's awkward because: > >- All queries run as `postgres' so you can't do per-user limiting very eas= ily > >- The postmaster doesn't have a way to set the=20 >nice level and ionice level when it forks a=20 >backend, nor does the backend have any way to do=20 >it later. You can use your own user-defined C functions for this, though. Postmaster hasn't a way to modify the system nice=20 or ionice, but it can send signals to child=20 process. Sending a user signal to sleep=20 completely the child (i/o and cpu) or before any=20 i/o call can do the trick. Perhaps it's time to=20 add a query scheduler or a more complete/complex one in postgres. >-- >Craig Ringer ---------------------------------------------- Si la vida te da la espalda, =A1tocale el culo!=20=20
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