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Re: About these IPC parameters

From: The Hermit Hacker <scrappy(at)hub(dot)org>
To: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
Cc: Peter Eisentraut <peter_e(at)gmx(dot)net>, PostgreSQL Development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: About these IPC parameters
Date: 2000-07-27 15:27:00
Message-ID: Pine.BSF.4.21.0007271225560.2474-100000@thelab.hub.org (view raw or flat)
Thread:
Lists: pgsql-hackers
Peter ...

	Here is the 'latest and greatest' NOTES that one of the FreeBSD
guys has been working on for shared memory/semaphores ... not sure if it
helps or not, but I believe it was you that was working on "organizing
this"?

=============================
#####################################################################
# SYSV IPC KERNEL PARAMETERS
#
# Maximum number of entries in a semaphore map.
options         SEMMAP=31

# Maximum number of System V semaphores that can be used on the system at
# one time.
options         SEMMNI=11

# Total number of semaphores system wide
options         SEMMNS=61

# Total number of undo structures in system
options         SEMMNU=31

# Maximum number of System V semaphores that can be used by a single
process
# at one time.
options         SEMMSL=61

# Maximum number of operations that can be outstanding on a single System
V
# semaphore at one time.
options         SEMOPM=101

# Maximum number of undo operations that can be outstanding on a single
# System V semaphore at one time.
options         SEMUME=11

# Maximum number of shared memory pages system wide.
options         SHMALL=1025

# Maximum size, in bytes, of a single System V shared memory region.
options         SHMMAX="(SHMMAXPGS*PAGE_SIZE+1)"
options         SHMMAXPGS=1025

# Minimum size, in bytes, of a single System V shared memory region.
options         SHMMIN=2

# Maximum number of shared memory regions that can be used on the system
# at one time.
options         SHMMNI=33

# Maximum number of System V shared memory regions that can be attached to
# a single process at one time.
options         SHMSEG=9
========================================

On Thu, 27 Jul 2000, Bruce Momjian wrote:

> > So, SEMMNI and SEMMNS seem to be the most promising settings to change.
> > 
> > Is there any noteworthy relevance of some of the other parameters? I see
> > FAQ_BSDI talks about SEMUME and SEMMNU.
> 
> I wrote FAQ_BSDI because it was not trivial to figure out how to modify
> those parameters.  I figured other OS's either don't need to do it, or
> have an easier way of doing it.
> 
> -- 
>   Bruce Momjian                        |  http://candle.pha.pa.us
>   pgman(at)candle(dot)pha(dot)pa(dot)us               |  (610) 853-3000
>   +  If your life is a hard drive,     |  830 Blythe Avenue
>   +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026
> 

Marc G. Fournier                   ICQ#7615664               IRC Nick: Scrappy
Systems Administrator @ hub.org 
primary: scrappy(at)hub(dot)org           secondary: scrappy(at){freebsd|postgresql}.org 


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