Thank Greg and Grzegorz, As told i have large batch load to the postgres which i need to be run in low priority. Is it really throttling the data will help to lower the postgres workload for some queries?
> > > On Thu, Nov 5, 2009 at 9:36 AM, S Arvind <arvindwill@gmail.com> wrote: >> >> Hi Developers and Tuners, >> Is there any way to run some query in low priority and some query >> in higher priority in pg. The main reason for this is i need my main >> application(high priority) to be undisturbed by the sub application(low >> priority) which is running on same DB. Is there anyother good way to operate >> this? > > other than manually re-nicing back end, no.
And unfortunately this doesn't really work very well. renicing only affects cpu priority and usually it's i/o priority you want to adjust. Even if you can adjust i/o priority per process on your operating system the database often does i/o work for one process in another process or has times when a process is waiting on another process to finish i/o. So lowering the i/o priority of the low priority process might not have the desired effect of speeding up other processes.
Usually this isn't a problem unless you have a large batch load or something like that happening which consumes all available i/o. In that case you can sometimes reduce the i/o demand by just throttling the rate at which you send data to or read data from the server.