Re: Increasing size of SGA / Reducing Use of SGA

In article <CMtqtq.76x_at_encore.com> maldred_at_pinocchio.encore.com (Mark Aldred) writes:

>Newsgroups: comp.databases.oracle
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>From: maldred_at_pinocchio.encore.com (Mark Aldred)
>Organization: Encore Computer Corporation
>Date: Thu, 17 Mar 1994 19:44:13 GMT
>References: <1994Mar11.124410.978_at_gtewd.mtv.gtegsc.com>
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>SQLDBA> Connected.
>SQLDBA> ORA-07252: spcre: semget error, could not allocate semaphores.
>ULTRIX Error: 28: No space left on device
>Additional Information: 1
>SQLDBA>
>SQL*DBA complete.
>
>While you may still have enough shared memory available, Oracle may be trying
>to allocate the entire SGA in one shared memory region. If you kernel is
>configured so that a single shared memory region can not be as large as the
>SGA that you have configured then this problem would occur. There is a way
>to get oracle to use one or several shared memory regions for the SGA, but
>I am not sure what that is.
>
>Mark
A 7252 error means that oracle could not get enough semaphores from the operating system. The O/S kernel has to be reconfigured or the the "processes" parameter in $ORACLE_HOME/dbs/init$ORACLE_SID.ora must be reduced.

Oracle uses at least one semaphore per Oracle process. On some ports, such as Ultrix, it uses even more. Consult the port-specific documentation for instructions on how many semaphores need to be configured.

As to shared memory, Oracle automatically configures its shared memory segments to fit what is available. If the maximum size of a segment is smaller than what Oracle needs, Oracle allocates the number that are needed. The segments can be contiguous or disjoint.

                                    Rick
                                    Rick Wessman
				    Server Techologies - Network Products
				    Oracle Corporation
                                    rwessman_at_us.oracle.com