| LOCK_SGA - Shared Memory Segments - Solaris 2.5 - ORA-27125 [message #70902] |
Fri, 09 August 2002 12:58  |
Toyn
Messages: 36
Registered: April 2001
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Member |
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Hi,
I'm doing some performance tuning to my system, and one parameter I've been working with is lock_sga. I've ensured that my sga is within the limits of the shmsys:shminfo_shmmax Solaris system OS parameter. When lock_sga is disabled, my database comes up fine, however, when it is enabled, I get the following error:
SVRMGR> startup
ORA-27125: unable to create shared memory segment
SVR4 Error: 1: Not owner
Below is an explanation of the error I've found:
ORA-27125: unable to create shared memory segment
Cause: A call to shmget() failed.
Do I have to be the owner of shmget in order to lock my sga in memory? I'm logged into svrmgrl as oracle (I can't access the utility as root). Is lock_sga even available for this version of Solaris 2.5? I'd like to store my entire sga in memory, what do I have to do in order to accomplish this? Thanks!
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| Re: LOCK_SGA - Shared Memory Segments - Solaris 2.5 - ORA-27125 [message #70905 is a reply to message #70902] |
Sat, 10 August 2002 13:39  |
TomazZ
Messages: 7
Registered: August 2002
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Junior Member |
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From metalink:
This problem is caused by an operating system limitation, and occurs
when
the following two conditions are true:
o When the parameter LOCK_SGA is set to TRUE in the init.ora file, and
o When you are running on the Solaris platform.
The setting of the parameter LOCK_SGA=TRUE is not supported on Solaris.
On Solaris the function calls that Oracle uses to fix the SGA in memory can
only be done by root, but the Oracle executable is normally owned by Oracle.
The Oracle user does not have the required privileges to call the OS function
to fix the SGA in memory. Other platforms do not have this problem. Oracle
includes this parameter on Solaris because it is part of the generic code.
This feature on Solaris will not work until Sun changes their code so that
memory can be accessed by non-root users.
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| Re: LOCK_SGA - Shared Memory Segments - Solaris 2.5 - ORA-27125 [message #71985 is a reply to message #70905] |
Fri, 14 February 2003 09:50 |
VISHNU
Messages: 14
Registered: November 2001
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Junior Member |
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Same issue with Linux. In fact, setting lock_sga explicitly (either true or false) gives error. With lock_sga set to false, the following error occurs:
ORA-27123: unable to attach to shared memory segment
Linux Error: 22: Invalid argument
It looks like the theory that only root is allowed access might be valid. At least there is consistency in behavior across the Unix variants.
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