Tuning for PostGreSQL Database

Terry Lambert tlambert2 at mindspring.com
Fri Jul 25 23:35:04 PDT 2003


Christopher Weimann wrote:
> So I have conflicting documentation.
> 
> I have machine with 4Gig of ram.  What is the maximum
> value of SHMMAX on FreeBSD?

Ideally, you would use memory mapped files for this, and not System V
shared memory, so that the OS could implement swapping policies as it
saw fit, and could actually swap the data, if nevcessary, instead of
it sucking up huge amounts of wired memory.

In any case, POSIX deprecated SysV shared memory years ago, and
recommends that all code utilize shm_open instead, these days, if
you insist on using an interface that sucks up huge amounts of
wired pages and KVA space.

-- Terry


More information about the freebsd-performance mailing list