How to tell which IPC resouces belongs to which instance

Chunyu Hu's Weblog - How to tell which IPC resouces belongs to which instance: It's quite common that there are more than 1 Oracle instance on 1 host. For example,we run many standby databases instances on 1 host for cost reason.

Sometimes, we fail to restart some Oracle instance because the IPC resources allocated for it are not cleared up. We can run ipcs to list all the IPC resouces on the host, but the problem is that we have to find only the IPC resources allocated to the specific instance and remove them manually before we restart the specific instance.

sysresv
Oracle provides sysresv to tell out which instance has which IPC resources. Unfortunately, we find sysresv is not reliable many times.

oradebug ipc
SQL>oradebug ipc
On Solaris, if you run this command, it will generate a trace file under the user_dump_dest directory. The trace file will list all the shared memory segment and semaphores. By checking all the in-use IPC resouces for all running Oracle instances and the result from ipcs command, you can know which IPC resouces you can safely to remove.