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From "Johnny Kewl" <j...@kewlstuff.co.za>
Subject Re: Thread Interruption in large Database
Date Mon, 16 Jun 2008 22:03:46 GMT

----- Original Message ----- 
From: "PhilCope" <phil1.cope@ge.com>
To: <derby-user@db.apache.org>
Sent: Monday, June 16, 2008 3:58 PM
Subject: Thread Interruption in large Database

> I have a large cloudscape 5 database (over 5million records) and I have 
> found
> that when a ResultsSet includes all or many of these records, the initial
> call to ResultsSet.next() takes a very long (but finite) time (I would
> estimate about 10-15mins) . I can (indeed have) arrange the code so that
> this call occurs in a separate java thread which can be interrupted from 
> the
> UI thread. BUT, as you may know, java threads that are set to as 
> interrupted
> continue to execute until either application code or some "system" calls
> actually check the interrupted state of the running thread.
> So, given this background info, my questions on Derby are
> 1. Have any significant performance improvements been made such that, for
> databases of this size, migrating from cloudscape to Derby would provide a
> significantly better response time ?
> 2. If not, are there any improvements to the responsiveness of the
> timeconsuming call to .next() to the setting of the interrupted flag on 
> the
> current thread in Derby ?
> Thanks
> Phil Cope

Phil, it actaully sounds like a design issue... are the fields are indexed 
and do you have to bring back all 5 mil records and a step through them... 
why not 10 at a time or something.
I think any dB (machine mem, heap whatever) will start to take strain with a 
5 million recordset.
Whats going to happen when the dB has 50 million records? The design should 
not depend on it.
ie if the search fields are indexed and you bring back 50 at a time, it 
should be pretty quick.
Sooner or later you going to get out of mem errors from Java... sounds like 
it anyway.

Good luck ;)

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