RE: time out mechanism for QO/QE

["Douglas Olson" <dlolson@lbl.gov>]

I like the "swap to disk" model. I think the following scenario
may turn out to be a popular one:
1. Physicist runs some GUI with QO in it, makes
   a new query, possibly even does execute on it.
   Gets query token, then exits GUI.
2. Some time later physicists submits batch jobs
   using this query token.  Parallelism is acheived
   by multiple batch jobs with single query token.
   When some iterator gets the message that the final
   event in the query has been delivered, it should
   issue the done message back to QM.

There could be a long time between 1 and 2, with no
active QO in existance but the query is still valid.
It would be useful for the persistent query to have
info like owner, date/time created  that an administrator
could use to clean up "dead" queries, but I don't think
there should be any automatic timeout.  It could be
implemented that the QO could specify a lifetime for
a specific query when it is created, but that seems
like an unnecessary refinement for now.

Doug

> -----Original Message-----
> From: Henrik Nordberg [mailto:hnordberg@lbl.gov]
> Sent: Wednesday, November 11, 1998 2:15 PM
> To: gcdev
> Subject: time out mechanism for QO/QE
> 
> 
> Hello,
> 
> since QE is keeping information in memory for each query, it's desirable
> to get rid of "dead" queries. How about having the QO ping the QE
> every now and then. If a query has been idle for a certain time, then
> QE could delete it and abort() it. An alternative would be to swap it
> to disk.
> 
> ?
> 
>  - Henrik
> _________________________________________
> Henrik Nordberg       <hnordberg@lbl.gov>
> Scientific Data Management Research Group
> Lawrence Berkeley National Laboratory
>