Horton

Re: Unexpected "shared memory block is still in use"

Peter Eisentraut <peter.eisentraut@2ndquadrant.com>

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From: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Noah Misch <noah@leadboat.com>, pgsql-hackers@lists.postgresql.org
Date: 2019-09-05T12:28:08Z
Lists: pgsql-hackers 
On 2019-09-04 16:59, Tom Lane wrote:
>> A related point, perhaps we should change the key printed into
>> postmaster.pid to be in hexadecimal format ("0x08x") so that it matches
>> what ipcs prints.
> Hmm, that depends on whose ipcs you use :-(.  A quick survey
> of my machines says it's
> 
>                 key     shmid
> 
> Linux:          hex     decimal
> FreeBSD:        decimal decimal
> NetBSD:         decimal decimal
> OpenBSD:        decimal decimal
> macOS:          hex     decimal
> HPUX:           hex     (not printed)
> 
> There's certainly room to argue that hex+decimal is most popular,
> but I'm not sure that that outweighs possible compatibility issues
> from changing postmaster.pid contents.  (Admittedly, it's not real
> clear that anything would be paying attention to the shmem key,
> so maybe there's no compatibility issue.)

Let's just leave it decimal then.  At least then it's easier to compare
it to ls -i output.

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Commits

  1. Use data directory inode number, not port, to select SysV resource keys.

  2. Cope with EINVAL and EIDRM shmat() failures in PGSharedMemoryAttach.

  3. Consistently test for in-use shared memory.