On Sun, 30 Jan 2005 20:50:21 +0000, Richard Poole <rp@xxxxxxxxxxxxxxx> wrote: > On Sun, Jan 30, 2005 at 03:21:25PM -0500, Rick Apichairuk wrote: > > > I am trying to increase the number of max_connections to 200 and found > > out I couldn't even start postgresql. So I tried to increase > > max_connections gradually (currently at 50 from 40 default) and adjust > > shared memory settings along the way. Even at 50 max_connections, I > > still cannot get postgresql to start. > > > > The following is the error message I receive: > > > > pgsql FATAL: could not create shared memory segment: Invalid argument > > DETAIL: Failed system call was shmget(key=5432001, size=35323904, > > 03600). > > > To reduce the request size (currently 35323904 bytes), > > > kern.ipc.shmmax: 33554432 > > Looks like the request size is just higher than shmmax. The majority of > the request is for the shared buffers, so if you can't increase shmmax > any more you can reduce your shared buffers downwards from 4096 and this > will give you some room for more connections. > > > Richard > Thanks... I missed that completely (need sleep!). I will try to bump up my SHMMAXPGS from 262144 to 400000. Is the shared_buffers per process? The reason I ask is the formula given on http://www.postgresql.org/docs/7.4/static/kernel-resources.html for calculating how much SHMMAX you need is: SHMMAX = 250 kB + 8.2 kB * shared_buffers + 14.2 kB * max_connections up to infinity If it were per process (connection) shouldn't it be: SHMMAX = (250 kB + 8.2 kB * shared_buffers + 14.2 kB) * max_connections up to infinity Also the examples for FreeBSD are: options SYSVSHM options SHMMAXPGS=4096 options SHMSEG=256 options SYSVSEM options SEMMNI=256 options SEMMNS=512 options SEMMNU=256 options SEMMAP=256 How many connections is this supposed to support? Thanks in advance. ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to majordomo@xxxxxxxxxxxxxx
