I get this when I try to start up a freshly compiled beta4 on OS X 
10.2.6:

FATAL:  could not create shared memory segment: Invalid argument

I saw a previous thread on this for beta2. It sounded like this was a 
bug that was to be fixed in beta3, but I'm still having this problem 
with beta4.

Thanks,

John DeSoi, Ph.D.


Fri, 24 Oct 2003 08:43:10 -0400
John DeSoi <jd@icx.net>
shared memory on OS X - 7.4beta4

I don't know what this error is particularly, but just to say that 7.4beta5
compiles and starts up fine on my OSX 10.2.8 machine

Cheers

Adam



> I get this when I try to start up a freshly compiled beta4 on OS X
> 10.2.6:
> 
> FATAL:  could not create shared memory segment: Invalid argument
> 
> I saw a previous thread on this for beta2. It sounded like this was a
> bug that was to be fixed in beta3, but I'm still having this problem
> with beta4.
> 
> Thanks,
> 
> John DeSoi, Ph.D.
> 
> 
> ---------------------------(end of broadcast)---------------------------
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Fri, 24 Oct 2003 15:19:36 +0100
Adam Witney <awitney@sghms.ac.uk>
Re: shared memory on OS X - 7.4beta4
>>>>> "JD" == John DeSoi <jd@icx.net> writes:

JD> I get this when I try to start up a freshly compiled beta4 on OS X
JD> 10.2.6:

JD> FATAL:  could not create shared memory segment: Invalid argument


How much SHM are you requesting (shared_buffers), and does the system
allow for that much?  There's some bootup script you can modify in OSX
to up that limit if you need.  Check google and/or Postgres' techdocs
site.


-- 
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Vivek Khera, Ph.D.                Khera Communications, Inc.
Internet: khera@kciLink.com       Rockville, MD       +1-240-453-8497
AIM: vivekkhera Y!: vivek_khera   http://www.khera.org/~vivek/

Fri, 24 Oct 2003 11:26:13 -0400
Vivek Khera <khera@kcilink.com>
Re: shared memory on OS X - 7.4beta4
Hi all,
Just wanted to know how postgres handles semaphores. Was hoping that i can
can use the locks defined in lwlock.h and lwlock.c . If i create a new
lock and then use LockAcquire and
LockRelease when I want a process to start and stop will this work?

Nailah




Fri, 24 Oct 2003 11:41:56 -0400 (EDT)
Nailah Ogeer <ogeer@cs.queensu.ca>
Semaphores
Nailah Ogeer wrote:
> Hi all,
> Just wanted to know how postgres handles semaphores. Was hoping that i can
> can use the locks defined in lwlock.h and lwlock.c . If i create a new
> lock and then use LockAcquire and
> LockRelease when I want a process to start and stop will this work?

Uh, well, we usually try to get a lock via a test-and-set assembly
language call into shared memory, and if we fail, we then get a
semaphore and wait for someone to wake us up.

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073

Fri, 24 Oct 2003 11:49:06 -0400 (EDT)
Bruce Momjian <pgman@candle.pha.pa.us>
Re: [HACKERS] Semaphores

On Friday, October 24, 2003, at 11:26 AM, Vivek Khera wrote:

> How much SHM are you requesting (shared_buffers), and does the system
> allow for that much?  There's some bootup script you can modify in OSX
> to up that limit if you need.  Check google and/or Postgres' techdocs
> site.

I did a default configure and did not change anything in the .conf 
file. It requests 10444800 bytes. But even if I drop max_connections 
down to 10, it still won't start. Yes, I can modify SHMMAX for the 
operating system to make it work but I'm trying to understand why I 
need to do this when it was not necessary under 7.3 or an earlier 7.4 
development build (pre beta 1). I was hoping it is a bug, because I 
think it hurts the adoption of Postgresql if I have to worry about a 
lot of low level OS settings just to setup a simple database.

Best,

John DeSoi, Ph.D.


Fri, 24 Oct 2003 13:07:06 -0400
John DeSoi <jd@icx.net>
Re: shared memory on OS X - 7.4beta4

On Friday, October 24, 2003, at 10:19 AM, Adam Witney wrote:

> I don't know what this error is particularly, but just to say that 
> 7.4beta5
> compiles and starts up fine on my OSX 10.2.8 machine

OK, I compiled beta 5 and put my rest SHMMAX back to the default 
settings as provided by OS X. Still the same error:

FATAL:  could not create shared memory segment: Invalid argument
DETAIL:  Failed system call was shmget(key=5432001, size=10444800, 
03600).
HINT:  This error usually means that PostgreSQL's request for a shared 
memory segment exceeded your kernel's SHMMAX parameter.  You can either 
reduce the request size or reconfigure the kernel with larger SHMMAX.  
To reduce the request size (currently 10444800 bytes), reduce 
PostgreSQL's shared_buffers parameter (currently 1000) and/or its 
max_connections parameter (currently 100).
	If the request size is already small, it's possible that it is less 
than your kernel's SHMMIN parameter, in which case raising the request 
size or reconfiguring SHMMIN is called for.
	The PostgreSQL documentation contains more information about shared 
memory configuration.

Here is how I configured it:

./configure --prefix=/Unix/postgresql --enable-locale 
--without-readline --with-includes=/sw/include --with-libraries=/sw/lib 
--with-openssl=/sw/lib


Next I upgraded to 10.2.8. Same issue.

So you have not modified your memory settings in 
/System/Library/StartupItems/SystemTuning/SystemTuning and you don't 
get this error?

I'm using a PowerBook G4 with 512M of memory.

Thanks,

John DeSoi, Ph.D.


Sat, 25 Oct 2003 21:01:13 -0400
John DeSoi <jd@icx.net>
Re: shared memory on OS X - 7.4beta4
On 26/10/03 1:01 am, "John DeSoi" <jd@icx.net> wrote:

> 
> On Friday, October 24, 2003, at 10:19 AM, Adam Witney wrote:
> 
>> I don't know what this error is particularly, but just to say that
>> 7.4beta5
>> compiles and starts up fine on my OSX 10.2.8 machine
> 
> OK, I compiled beta 5 and put my rest SHMMAX back to the default
> settings as provided by OS X. Still the same error:
> 
> FATAL:  could not create shared memory segment: Invalid argument
> DETAIL:  Failed system call was shmget(key=5432001, size=10444800,
> 03600).
> HINT:  This error usually means that PostgreSQL's request for a shared
> memory segment exceeded your kernel's SHMMAX parameter.  You can either
> reduce the request size or reconfigure the kernel with larger SHMMAX.
> To reduce the request size (currently 10444800 bytes), reduce
> PostgreSQL's shared_buffers parameter (currently 1000) and/or its
> max_connections parameter (currently 100).
> If the request size is already small, it's possible that it is less
> than your kernel's SHMMIN parameter, in which case raising the request
> size or reconfiguring SHMMIN is called for.
> The PostgreSQL documentation contains more information about shared
> memory configuration.
> 
> Here is how I configured it:
> 
> ./configure --prefix=/Unix/postgresql --enable-locale
> --without-readline --with-includes=/sw/include --with-libraries=/sw/lib
> --with-openssl=/sw/lib
> 
> 
> Next I upgraded to 10.2.8. Same issue.
> 
> So you have not modified your memory settings in
> /System/Library/StartupItems/SystemTuning/SystemTuning and you don't
> get this error?

Ah, yes I did change these... Mine are set to

    sysctl -w kern.sysv.shmmax=4194304
    sysctl -w kern.sysv.shmmin=1
    sysctl -w kern.sysv.shmmni=32
    sysctl -w kern.sysv.shmseg=8
    sysctl -w kern.sysv.shmall=1024

> I'm using a PowerBook G4 with 512M of memory.

Same as me

Do you have many other applications running? Or an old version of
PostgreSQL... I found when running the regression tests I had to shut down
my 7.3.2 installation

Cheers

adam





adam


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Sun, 26 Oct 2003 15:16:54 +0000
Adam Witney <awitney@sghms.ac.uk>
Re: shared memory on OS X - 7.4beta4
Adam,

On Sunday, October 26, 2003, at 10:16 AM, Adam Witney wrote:

> Ah, yes I did change these... Mine are set to
>
>     sysctl -w kern.sysv.shmmax=4194304
>     sysctl -w kern.sysv.shmmin=1
>     sysctl -w kern.sysv.shmmni=32
>     sysctl -w kern.sysv.shmseg=8
>     sysctl -w kern.sysv.shmall=1024


OK, this is what I was after. I did not have to change any of this for 
7.3, but now 7.4 does not work unless on a standard OS X installation 
unless the user modifies these system settings. I can live with it, but 
I was hoping it might be a bug that could be resolved before the final 
7.4. Every person that installs on OS X is going to run into this. 
Tracking it down and understanding what you have to change is not 
simple for us OS X users that are not familiar with Unix :).

Best,

John DeSoi, Ph.D.


Sun, 26 Oct 2003 16:41:16 -0500
John DeSoi <jd@icx.net>
Re: shared memory on OS X - 7.4beta4
On Sun, Oct 26, 2003 at 04:41:16PM -0500, John DeSoi wrote:

> On Sunday, October 26, 2003, at 10:16 AM, Adam Witney wrote:
> 
> >Ah, yes I did change these... Mine are set to
> >
> >    sysctl -w kern.sysv.shmmax=4194304
> >    sysctl -w kern.sysv.shmmin=1
> >    sysctl -w kern.sysv.shmmni=32
> >    sysctl -w kern.sysv.shmseg=8
> >    sysctl -w kern.sysv.shmall=1024
> 
> 
> OK, this is what I was after. I did not have to change any of this for 
> 7.3, but now 7.4 does not work unless on a standard OS X installation 
> unless the user modifies these system settings.

Huh, this is strange.  IIRC during the installation process, initdb is
supposed to determine which values actually work; those are affected by
the shmmax operating system mostly, and the idea is to enable the
installation process to pick more reasonable values out-of-the-box for
memory usage that will work on your system.

How did you install Postgres, and what values did initdb pick for
shared_buffers and max_connections?

-- 
Alvaro Herrera (<alvherre[a]dcc.uchile.cl>)
"Puedes vivir solo una vez, pero si lo haces bien, una vez es suficiente"

Sun, 26 Oct 2003 19:51:37 -0300
Alvaro Herrera <alvherre@dcc.uchile.cl>
Re: shared memory on OS X - 7.4beta4
On 26/10/03 9:41 pm, "John DeSoi" <jd@icx.net> wrote:

> Adam,
> 
> On Sunday, October 26, 2003, at 10:16 AM, Adam Witney wrote:
> 
>> Ah, yes I did change these... Mine are set to
>> 
>>     sysctl -w kern.sysv.shmmax=4194304
>>     sysctl -w kern.sysv.shmmin=1
>>     sysctl -w kern.sysv.shmmni=32
>>     sysctl -w kern.sysv.shmseg=8
>>     sysctl -w kern.sysv.shmall=1024
> 
> 
> OK, this is what I was after. I did not have to change any of this for
> 7.3, but now 7.4 does not work unless on a standard OS X installation
> unless the user modifies these system settings. I can live with it, but
> I was hoping it might be a bug that could be resolved before the final
> 7.4. Every person that installs on OS X is going to run into this.
> Tracking it down and understanding what you have to change is not
> simple for us OS X users that are not familiar with Unix :).


Well I had to change this for 7.3 to run and I never set it back to try 7.4
with the defaults

But I think the 7.4 installation process checks for the best values of
max_connections and shared_buffers that for the current settings shmmax
settings

But someone else on the list is probably better to answer the technical
details of this

adam


Mon, 27 Oct 2003 00:07:52 +0000
Adam Witney <awitney@sghms.ac.uk>
Re: shared memory on OS X - 7.4beta4

On Sunday, October 26, 2003, at 05:51 PM, Alvaro Herrera wrote:

> Huh, this is strange.  IIRC during the installation process, initdb is
> supposed to determine which values actually work; those are affected by
> the shmmax operating system mostly, and the idea is to enable the
> installation process to pick more reasonable values out-of-the-box for
> memory usage that will work on your system.
>
> How did you install Postgres, and what values did initdb pick for
> shared_buffers and max_connections?

Here were my steps to install and attempt to run it:

Install (clean install to a new directory)

./configure --prefix=/Unix/postgresql --enable-locale 
--without-readline --with-includes=/sw/include --with-libraries=/sw/lib 
--with-openssl=/sw/lib
make
make install

Initdb:

initdb -D /data/pgtest --no-locale

Startup:

pg_ctl start -D /data/pgtest -l /data/pgtest/logfile -o '-i -p 5432'


the postgresql.conf has
max_connections = 100
shared_buffers = 1000

And here are are the default settings for OS X 10.2.6:

     sysctl -w kern.sysv.shmmax=4194304
     sysctl -w kern.sysv.shmmin=1
     sysctl -w kern.sysv.shmmni=32
     sysctl -w kern.sysv.shmseg=8
     sysctl -w kern.sysv.shmall=1024


Sun, 26 Oct 2003 22:17:50 -0500
John DeSoi <jd@icx.net>
Re: shared memory on OS X - 7.4beta4
On Sun, Oct 26, 2003 at 10:17:50PM -0500, John DeSoi wrote:

> On Sunday, October 26, 2003, at 05:51 PM, Alvaro Herrera wrote:
> 
> >How did you install Postgres, and what values did initdb pick for
> >shared_buffers and max_connections?
> 
> the postgresql.conf has
> max_connections = 100
> shared_buffers = 1000
> 
> And here are are the default settings for OS X 10.2.6:
> 
>     sysctl -w kern.sysv.shmmax=4194304

Well, I can only say that if I lower shmmax to that value, initdb picks
max_connections = 50
shared_buffers = 300

I remember there was a subtle bug in earlier versions corrected after
beta4.  Can you try beta5 and see if it works for you?  But with beta4 I
get 400/20 instead of 300/50, so this is probably not the same problem.

1000/100 are actually the largest probed values, so maybe initdb is
failing to probe or the postgresql.conf is not written correctly.  Does
the initdb output actually say that it is going to use 1000/100?  And is
the generated postgresql.conf by that initdb run the file that gets
actually used?

Maybe this is useless anyway, because I'm on Linux.  Someone with an
actual OS X system could probably be a lot more helpful.

-- 
Alvaro Herrera (<alvherre[@]dcc.uchile.cl>)
"Cuando no hay humildad las personas se degradan" (A. Christie)

Mon, 27 Oct 2003 01:13:01 -0300
Alvaro Herrera Munoz <alvherre@dcc.uchile.cl>
Re: shared memory on OS X - 7.4beta4

On Sunday, October 26, 2003, at 11:13 PM, Alvaro Herrera Munoz wrote:

>
> I remember there was a subtle bug in earlier versions corrected after
> beta4.  Can you try beta5 and see if it works for you?  But with beta4  
> I
> get 400/20 instead of 300/50, so this is probably not the same problem.

I mentioned earlier in the thread -- I did try beta5 -- same result.

>
> 1000/100 are actually the largest probed values, so maybe initdb is
> failing to probe or the postgresql.conf is not written correctly.  Does
> the initdb output actually say that it is going to use 1000/100?  And  
> is
> the generated postgresql.conf by that initdb run the file that gets
> actually used?
>

I don't recall seeing the initdb output, but I'm sure the generated  
postgresql.conf is the one being used. I lowered max_connections and  
saw lower numbers in the failed request when I tried to start the  
server.

Best,

John DeSoi, Ph.D.




#----------------------------------------------------------------------- 
----
# CONNECTIONS AND AUTHENTICATION
#----------------------------------------------------------------------- 
----

# - Connection Settings -

#tcpip_socket = false
max_connections = 100
	# note: increasing max_connections costs about 500 bytes of shared
	# memory per connection slot, in addition to costs from shared_buffers
         # and max_locks_per_transaction.
#superuser_reserved_connections = 2
#port = 5432
#unix_socket_directory = ''
#unix_socket_group = ''
#unix_socket_permissions = 0777	# octal
#virtual_host = ''		# what interface to listen on; defaults to any
#rendezvous_name = ''		# defaults to the computer name

# - Security & Authentication -

#authentication_timeout = 60	# 1-600, in seconds
#ssl = false
#password_encryption = true
#krb_server_keyfile = ''
#db_user_namespace = false


#----------------------------------------------------------------------- 
----
# RESOURCE USAGE (except WAL)
#----------------------------------------------------------------------- 
----

# - Memory -

shared_buffers = 1000		# min 16, at least max_connections*2, 8KB each
#sort_mem = 1024		# min 64, size in KB
#vacuum_mem = 8192	


Mon, 27 Oct 2003 00:46:48 -0500
John DeSoi <jd@icx.net>
Re: shared memory on OS X - 7.4beta4
On 27/10/03 5:46 am, "John DeSoi" <jd@icx.net> wrote:

> 
> On Sunday, October 26, 2003, at 11:13 PM, Alvaro Herrera Munoz wrote:
> 
>> 
>> I remember there was a subtle bug in earlier versions corrected after
>> beta4.  Can you try beta5 and see if it works for you?  But with beta4
>> I
>> get 400/20 instead of 300/50, so this is probably not the same problem.
> 
> I mentioned earlier in the thread -- I did try beta5 -- same result.
> 
>> 
>> 1000/100 are actually the largest probed values, so maybe initdb is
>> failing to probe or the postgresql.conf is not written correctly.  Does
>> the initdb output actually say that it is going to use 1000/100?  And
>> is
>> the generated postgresql.conf by that initdb run the file that gets
>> actually used?
>> 
> 
> I don't recall seeing the initdb output, but I'm sure the generated
> postgresql.conf is the one being used. I lowered max_connections and
> saw lower numbers in the failed request when I tried to start the
> server.

My current settings are

max_connections = 32
shared_buffers = 100

But the settings picked automatically by the installation were

max_connections = 50
shared_buffers = 300

But I found this would not always start as I often have lots of applications
open (this is my laptop) and I had trouble running both 7.3 and 7.4beta5 at
the same time

Cheers

Adam


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Mon, 27 Oct 2003 08:54:21 +0000
Adam Witney <awitney@sghms.ac.uk>
Re: shared memory on OS X - 7.4beta4
>> And here are are the default settings for OS X 10.2.6:
>> 
>>     sysctl -w kern.sysv.shmmax=4194304
>
>Well, I can only say that if I lower shmmax to that value, initdb picks
>max_connections = 50
>shared_buffers = 300

I just did a fresh install of 7.4b5 on a fresh install of MacOS 10.3, and initdb
picked those same values for postgresql.conf.  PostgreSQL started up the first
time successfully, but then refused to start again even after restarting the
computer until I reduced shared_buffers.

Now to figure out why sysctl -w kern.sysv.shmmax=<some_reasonable_value> doesn't
seem to work on 10.3...

Jim Crate

Tue, 28 Oct 2003 10:44:41 -0500
Jim Crate <jcrate@deepskytech.com>
Re: shared memory on OS X - 7.4beta4

Slightly off topic confirmations...

>>> And here are are the default settings for OS X 10.2.6:
>>>
>>>     sysctl -w kern.sysv.shmmax=4194304

Seems to be the default on 10.2.8 as well.

10.1.5 doesn't seem to have a kern.sysv.* section:

[broccoli:~] erics% sysctl kern.sysv.shmmax
second level name sysv in kern.sysv.shmmax is invalid

>>
>> Well, I can only say that if I lower shmmax to that value, initdb 
>> picks
>> max_connections = 50
>> shared_buffers = 300
>
> I just did a fresh install of 7.4b5 on a fresh install of MacOS 10.3, 
> and initdb
> picked those same values for postgresql.conf.  PostgreSQL started up 
> the first
> time successfully, but then refused to start again even after 
> restarting the
> computer until I reduced shared_buffers.

I've had cases in 10.1.x where after hammering on the database for a 
while and having to restart it, there was no longer enough shared 
memory to start postgres, requiring a restart of the computer. On 10.1, 
I couldn't even get it to change the shmmax value, necessitating some 
very low buffer numbers (nearly out of the box for pg 7.2, yes, that 
bad).



eric


Tue, 28 Oct 2003 10:20:06 -0800
Eric Soroos <eric-psql@soroos.net>
Re: shared memory on OS X - 7.4beta4
>>>>> "JC" == Jim Crate <jcrate@deepskytech.com> writes:

JC> Now to figure out why sysctl -w
JC> kern.sysv.shmmax=<some_reasonable_value> doesn't seem to work on
JC> 10.3...

I believe you must do it at boot time, not after.  ie, it must be done
by one of the startup scripts.


-- 
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Vivek Khera, Ph.D.                Khera Communications, Inc.
Internet: khera@kciLink.com       Rockville, MD       +1-240-453-8497
AIM: vivekkhera Y!: vivek_khera   http://www.khera.org/~vivek/

Tue, 28 Oct 2003 14:16:37 -0500
Vivek Khera <khera@kcilink.com>
Re: shared memory on OS X - 7.4beta4
John DeSoi <jd@icx.net> writes:
> OK, I compiled beta 5 and put my rest SHMMAX back to the default 
> settings as provided by OS X. Still the same error:

> FATAL:  could not create shared memory segment: Invalid argument
> DETAIL:  Failed system call was shmget(key=5432001, size=10444800, 
> 03600).
> HINT:  This error usually means that PostgreSQL's request for a shared 
> memory segment exceeded your kernel's SHMMAX parameter.  You can either 
> reduce the request size or reconfigure the kernel with larger SHMMAX.  
> To reduce the request size (currently 10444800 bytes), reduce 
> PostgreSQL's shared_buffers parameter (currently 1000) and/or its 
> max_connections parameter (currently 100).

There is something very wrong here.  On my OS X machine, initdb selects
non-default shared_buffers and max_connections (300 and 50 respectively,
when using 7.4beta5).  Why is that failing to happen on yours?  I can
see two possibilities: either initdb is failing to notice that it needs
smaller-than-default values, or it's somehow failing to insert those
values into the constructed postgresql.conf file.  You could determine
which is happening by looking at the output of initdb to see what it
reports.

[ thinks for a bit... ]  Hmm.  You *are* using the postgresql.conf file
that initdb built, aren't you?

			regards, tom lane

Tue, 28 Oct 2003 15:13:51 -0500
Tom Lane <tgl@sss.pgh.pa.us>
Re: shared memory on OS X - 7.4beta4 

On Tuesday, October 28, 2003, at 03:13 PM, Tom Lane wrote:

> There is something very wrong here.  On my OS X machine, initdb selects
> non-default shared_buffers and max_connections (300 and 50 
> respectively,
> when using 7.4beta5).  Why is that failing to happen on yours?  I can
> see two possibilities: either initdb is failing to notice that it needs
> smaller-than-default values, or it's somehow failing to insert those
> values into the constructed postgresql.conf file.  You could determine
> which is happening by looking at the output of initdb to see what it
> reports.

I set the memory parameters back to their defaults, and now: it works. 
I'm getting 300 and 50 with initdb. I don't recall what the output form 
initdb was from previous attempts, but the .conf file always had 1000 
and 100.


>
> [ thinks for a bit... ]  Hmm.  You *are* using the postgresql.conf file
> that initdb built, aren't you?

I have never changed anything in this file (or replaced it). I did not 
even know what the shared_buffers parameter was for until I ran into 
this problem.

What version of OS X are you running? I thought I replicated the 
problem after upgrading to 10.2.8, but now I'm not certain I ran initdb 
again (I may have just rebuilt beta 5). So possibly it could be a 
difference between 10.2.6 and 10.2.8. If not, I have no clue. I'll 
report back if I find anything.

Best,

John DeSoi, Ph.D.


Tue, 28 Oct 2003 21:38:29 -0500
John DeSoi <jd@icx.net>
Re: shared memory on OS X - 7.4beta4 
John DeSoi <jd@icx.net> writes:
> What version of OS X are you running? I thought I replicated the 
> problem after upgrading to 10.2.8, but now I'm not certain I ran initdb 
> again (I may have just rebuilt beta 5). So possibly it could be a 
> difference between 10.2.6 and 10.2.8. If not, I have no clue. I'll 
> report back if I find anything.

I'm running 10.2.6 (a pretty fresh install, see prior bellyaching about
hardware problems with my laptop ;-)).  IIRC, someone else reported
success with a clean 10.2.8 installation in this thread.  I have also
checked PG against a 10.3 beta recently, and so have other people.
It's fairly likely that there are problems with 10.1, if anyone still
uses that, but I have no reason to think that PG 7.4 will fail with
either 10.2.* or 10.3.

			regards, tom lane

Wed, 29 Oct 2003 00:07:59 -0500
Tom Lane <tgl@sss.pgh.pa.us>
Re: shared memory on OS X - 7.4beta4 