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Date: Thu, 07 Apr 2005 12:02:58 +0100
From: David Van Couvering <David.Vancouvering@Sun.COM>
Subject: Re: more background threads
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References: <424AA335.1090405@sun.com> <424C5BC6.10900@sbcglobal.net>
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So I suppose conceivably you could have multiple systems in a VM if you 
have multiple classloaders, each of which loads its own copy of the JDBC 
driver class...

David

Daniel John Debrunner wrote:

> David Van Couvering wrote:
> 
> 
>>OK...  I'm still trying to get clear on your concepts and terms -- how
>>is a "system" defined?  I'm thinking "all of Derby" within a given VM?
> 
> 
> Correct. A system corresponds to the loading of Derby's JDBC driver
> within a JVM, a system can have multiple databases open within that JVM.
> 
> 
> 
>>Before I spend a lot more time on this: are there other things that are
>>reasonable in scale and scope you could really use my help on that are
>>generally felt to be of higher priority?  I don't need to spend a lot of
>>time on this if it currently works pretty well and is not causing a lot
>>of pain or problems...
> 
> 
> Apart from fixing the issue of too many Java threads when a large number
> of databases are active, I see the cleanup in this area as a step
> towards supporting:
> 
>  - timed events - java.util.TimerTask integration, for setQueryTimeout
> at least
> 
>  - Serviceable items that can be executed during idle time, e.g.
> background data flushing, space reclaimation, background statistics
> gathering, etc.
> 
> While these items could be fitted into the current scheme, I think a
> cleanup would make it easier.
> 
> Dan.
>