Slow DB / outstanding requests

[Alan DeKok]

Johan Meiring wrote:
> I am running 2.1.12 on a production server.
> The server is (was) severly underpowered and the database was straining.

  Don't do that....

> I was expenting the normal - "rejecting duplicate request".  (Cant remember exact error).

  Pretty much, yes.

> Then the server received about 30 access requests in about .1 second
> 
> It then went into a state where the following appeared over and over in the log:
> 
> Mon Sep 12 11:33:46 2011 : Info: WARNING: Child is hung for request 647 in component <core> module <queue>.
> Mon Sep 12 11:33:46 2011 : Info: WARNING: Child is hung for request 648 in component <core> module <queue>.

  Hmmm... it's *really* slow.  The requests are placed in a queue for
the child threads to pick up.  But... if the system is locked, they'll
sit in the queue for a long time.

> It never recovered.
> Had to be restarted.
> Even with no database queries outstanding.
> 
> Dont know if 2.1.12 has more "difficulty" with slow databases?

 It shouldn't.

> Unfortunately dont have more info, so this can probably be ignored.

  There are ways of addressing it...

  Alan DeKok.