Re: BUG #7885: postmaster panic on startup does not release shared memory

When we panic, we PANIC, meaning we don't jump around looking for
cleanup stuff, which might make things worse. Postgres should never
panic, so it would be good if you found the cause of the panic.

Does restarting the server remove the old shared memory stuff?

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On Fri, Feb 15, 2013 at 06:33:21PM +0000, david(dot)thomas(at)enterprisedb(dot)com wrote:
> The following bug has been logged on the website:
>
> Bug reference: 7885
> Logged by: David Thomas
> Email address: david(dot)thomas(at)enterprisedb(dot)com
> PostgreSQL version: 9.2.3
> Operating system: CentOS 6.3
> Description:
>
> It seems that if the postmaster encounters a PANIC condition during startup,
> it leaves it's allocated shared memory segments around:
>
> -bash-4.1$ ipcs -a
>
> ------ Shared Memory Segments --------
> key shmid owner perms bytes nattch status
>
> ------ Semaphore Arrays --------
> key semid owner perms nsems
>
> ------ Message Queues --------
> key msqid owner perms used-bytes messages
>
> -bash-4.1$ /usr/pgsql-9.2/bin/postmaster --single -D
> /var/lib/pgsql/9.2/data/ test
> PANIC: could not locate a valid checkpoint record
> Aborted
> -bash-4.1$ ipcs -a
>
> ------ Shared Memory Segments --------
> key shmid owner perms bytes nattch status
> 0x00000001 753664 postgres 600 41279488 0
>
> ------ Semaphore Arrays --------
> key semid owner perms nsems
> 0x00000001 5439490 postgres 600 17
> 0x00000002 5472259 postgres 600 17
> 0x00000003 5505028 postgres 600 17
> 0x00000004 5537797 postgres 600 17
> 0x00000005 5570566 postgres 600 17
> 0x00000006 5603335 postgres 600 17
> 0x00000007 5636104 postgres 600 17
>
> ------ Message Queues --------
> key msqid owner perms used-bytes messages
>
> Considering that it was able to allocate this memory before the panic
> occurred, it should remove them before exiting.
>
>
>
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--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ It's impossible for everything to be true. +