On Thu, Dec 29, 2005 at 03:09:52PM +0530, surabhi.ahuja wrote: > I have a few questions: > 1. what is pg_xlog > someone told me that i can move pg_xlog to a different parttion in order to boost the performance? Does it work and how Yes, it works. How? By moving the directory (while the postmaster is not running) and creating a symlink in the right place. > 2. there is a parameter in postgresql.conf called max_connections. which is 100 be default. i want o decrease it to 20. > by doing this how much can i increase the value of shared buffers? > by default it is 1000, how much can i increase to in order to boost up the performance They have nothing to do with eachother. Depending on how much memory you have, the shared_buffers could be increased by a factor of 10. Max connections won't change anything there. > 3. What other things can i do to boost up the performance assuming that the stored procedures are well optimized. Google the web, or try the pgsql-performence mailing list. > 4. I recently tried to start postmaster. But it simply timed out. i tried to find out if there is any postmaster process running, but it was not running. > my question is that can u decrease this timeout, right now i think it takes some 1 or 2 minutes... Look in the logs for an error message. > 5. i have also seen multiple instances of postmaster. > in my script ot start postmaster i first check if it is running by doing pidof, and only if it is nor running i start it > still have seen multiple instances. > how did that happen? also if i stop postmaster, only one instance is stopped. Each connection appears as a new process, so pidof wont't work. You need to use the pidfile the postmaster creates. Why arn't you using one of the startup scripts provided? > is there any command to stop all instances of postmaster Are you sure you have more than one? > 6. what does ipcclean do? how do i know what shared memory was used by postmaster so that i can clear it, before starting postmaster PostgreSQL takes care of it's own ipc memory, you should never need to use ipcclean ever. > 7. some times if i do a dropdb abc(assuming abc is a database) > it displays a message can not remove directory 12345, although the database is dropped, what shuld be done in such a case? Please provide the exact error message. Oh, and while you're at it, what platform and what version of postgres. Without that info it's impossible to give any real help, Have a nice day, -- Martijn van Oosterhout <kleptog@xxxxxxxxx> http://svana.org/kleptog/ > Patent. n. Genius is 5% inspiration and 95% perspiration. A patent is a > tool for doing 5% of the work and then sitting around waiting for someone > else to do the other 95% so you can sue them.
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