Re: Cause of "can't wait without a PROC structure"

On Wed, 2002-09-25 at 09:52, Tom Lane wrote:
> I've identified the reason for the occasional "can't wait without a PROC
> structure" failures we've seen reported.  I had been thinking that this
> must occur during backend startup, before MyProc is initialized ...
> but I was mistaken.  Actually, it happens during backend shutdown,
> and the reason is that ProcKill (which releases the PGPROC structure
> and resets MyProc to NULL) is called before ShutdownBufferPoolAccess.
> But the latter tries to acquire the bufmgr LWLock.  If it has to wait,
> kaboom.
> 

Great news that you've identified the problem. We continue to see this
every few days and it's the only thing that takes our servers down over
weeks of pounding.

> The ordering of these shutdown hooks is the reverse of the ordering
> of the startup initialization of the modules.  It looks like we'll
> need to rejigger the startup ordering ... and it also looks like that's
> going to be a rather ticklish issue.  (See comments in BaseInit and
> InitPostgres.)  Any thoughts on how to do it?
> 

Sorry I can't add any insight at this level...but I can say that it
would be significant to my customer(s) and my ability to recommend PG to
future "ex-Oracle users" ;) to see a fix make it into the 7.3 final.

ss


Scott Shattuck
Technical Pursuit Inc.