LOCK_SGA Not Working (Doc ID 1274096.1)

Last updated on NOVEMBER 28, 2016

Applies to:

Oracle Database - Enterprise Edition - Version 10.2.0.1 and later
Information in this document applies to any platform.
***Checked for relevance on 19-Jul-2012***

Symptoms

LOCK_SGA is not working even if specified at the database startup.

Checking with the IPCS OS command we can see that the segment is not locked in memory:

Output of ipcs -m command:

------ Shared Memory Segments --------
key shmid owner perms bytes nattch status
0x60da43e0 2326528 oins 600 1579155456 27


From an OS trace of the startup we can see that the SHM_LOCK flag was set by the Oracle process:

10018 shmctl(2293760, IPC_64|IPC_RMID, 0) = 0
10018 shmget(0x60da43e0, 1579155456, IPC_CREAT|IPC_EXCL|SHM_HUGETLB|0600) = 2326528
10018 shmctl(2326528, IPC_64|SHM_LOCK, 0) = 0

Cause

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