Re: [PERFORM] configure shmmax on MAC OS X
Hello, I found that if you SHMALL value was less than your SHMMAX value, the value wouldn't take. J Tom Lane wrote: Qing Zhao <[EMAIL PROTECTED]> writes: My suspision is that the change i made in /etc/rc does not take effect.Is there a way to check it? sysctl has an option to show the values currently in effect. I believe that /etc/rc is the correct place to set shmmax on OSX 10.3 or later ... but we have seen prior reports of people having trouble getting the setting to "take". There may be some other constraint involved. sysctl -w kern.sysv.shmmax=4294967296 // byte Hmm, does sysctl work for values that exceed the range of int? There's no particularly good reason to try to set shmmax as high as you are trying anyhow; you really don't need more than a couple hundred meg in Postgres shared memory. It's better to leave the kernel to manage the bulk of your RAM. regards, tom lane ---(end of broadcast)--- TIP 4: Don't 'kill -9' the postmaster ---(end of broadcast)--- TIP 6: Have you searched our list archives? http://archives.postgresql.org
Re: [PERFORM] configure shmmax on MAC OS X
Qing Zhao <[EMAIL PROTECTED]> writes: > My suspision is that the change i made in /etc/rc does not take > effect.Is there a way to check it? sysctl has an option to show the values currently in effect. I believe that /etc/rc is the correct place to set shmmax on OSX 10.3 or later ... but we have seen prior reports of people having trouble getting the setting to "take". There may be some other constraint involved. > sysctl -w kern.sysv.shmmax=4294967296 // byte Hmm, does sysctl work for values that exceed the range of int? There's no particularly good reason to try to set shmmax as high as you are trying anyhow; you really don't need more than a couple hundred meg in Postgres shared memory. It's better to leave the kernel to manage the bulk of your RAM. regards, tom lane ---(end of broadcast)--- TIP 4: Don't 'kill -9' the postmaster
Re: [PERFORM] configure shmmax on MAC OS X
Tom: I used sysctl -A to see the kernel state, I got: kern.sysv.shmmax: -1 It looks the value is too big! Thanks! Qing On Apr 13, 2004, at 12:55 PM, Tom Lane wrote: Qing Zhao <[EMAIL PROTECTED]> writes: My suspision is that the change i made in /etc/rc does not take effect.Is there a way to check it? sysctl has an option to show the values currently in effect. I believe that /etc/rc is the correct place to set shmmax on OSX 10.3 or later ... but we have seen prior reports of people having trouble getting the setting to "take". There may be some other constraint involved. sysctl -w kern.sysv.shmmax=4294967296 // byte Hmm, does sysctl work for values that exceed the range of int? There's no particularly good reason to try to set shmmax as high as you are trying anyhow; you really don't need more than a couple hundred meg in Postgres shared memory. It's better to leave the kernel to manage the bulk of your RAM. regards, tom lane ---(end of broadcast)--- TIP 8: explain analyze is your friend
Re: [PERFORM] configure shmmax on MAC OS X
On OS X, I've always made these changes in: /System/Library/StartupItems/SystemTuning/SystemTuning and manually checked it with sysctl after reboot. Works for me. 100k buffers is probably overkill. There can be a performance penalty with too many buffers. See this lists' archives for more. 10k would probably be a better start. - Jeff >Hi, all, > >I have got a new MaC OS G5 with 8GB RAM. So i tried to increase >the shmmax in Kernel so that I can take advantage of the RAM. > >I searched the web and read the manual for PG7.4 chapter 16.5.1. >After that, I edited /etc/rc file: > >sysctl -w kern.sysv.shmmax=4294967296 // byte >sysctl -w kern.sysv.shmmin=1 >sysctl -w kern.sysv.shmmni=32 >sysctl -w kern.sysv.shmseg=8 >sysctl -w kern.sysv.shmall=1048576 //4kpage > >for 4G shared RAM. > >Then I changed postgresql.conf: >shared_buffer=10 //could be bigger? > >and restart the machine and postgres server. To my surprise, postgres server wouldn't >start, saying that the requested shared memory exceeds kernel's shmmax. > >My suspision is that the change i made in /etc/rc does not take effect.Is there a way >to check it? Is there an >up limit for how much RAM can be allocated for shared buffer in MAC OS X? Or >is there something wrong with my calculation in numbers? > >Thanks a lot! > >Qing > > >---(end of broadcast)--- >TIP 3: if posting/reading through Usenet, please send an appropriate > subscribe-nomail command to [EMAIL PROTECTED] so that your > message can get through to the mailing list cleanly -- Jeff Bohmer VisionLink, Inc. _ 303.402.0170 www.visionlink.org _ People. Tools. Change. Community. ---(end of broadcast)--- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
