Horton

Re: ERROR: invalid spinlock number: 0

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Michael Paquier <michael@paquier.xyz>
Cc: Thomas Munro <thomas.munro@gmail.com>, Fujii Masao <masao.fujii@oss.nttdata.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2021-02-15T21:28:05Z
Lists: pgsql-hackers 
Hi,

On 2021-02-15 19:45:21 +0900, Michael Paquier wrote:
> On Mon, Feb 15, 2021 at 10:47:05PM +1300, Thomas Munro wrote:
> > Why not initialise it in WalRcvShmemInit()?
> 
> I was thinking about doing that as well, but we have no real need to
> initialize this stuff in most cases, say standalone deployments.  In
> particular for the fallback implementation of atomics, we would
> prepare a spinlock for nothing.

So what? It's just about free to initialize a spinlock, whether it's
using the fallback implementation or not. Initializing upon walsender
startup adds a lot of complications, because e.g. somebody could already
hold the spinlock because the previous walsender just disconnected, and
they were looking at the stats.

Greetings,

Andres Freund

Commits

  1. Fix "invalid spinlock number: 0" error in pg_stat_wal_receiver.

  2. Display the time when the process started waiting for the lock, in pg_locks, take 2

  3. Display the time when the process started waiting for the lock, in pg_locks.

  4. Make pg_stat_wal_receiver consistent with the WAL receiver's shmem info