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From Matt Chambers <chamb...@imageworks.com>
Subject Re: top N reporting with derby
Date Wed, 14 May 2008 15:52:47 GMT

That is a possibility.  I could select out the oldest date add an hour 
to that and grab packets in that range.

Suavi Ali Demir wrote:
> If 100 is not absolute necessity, you can give datetime ranges. For 
> example select 1 hour of logs at a time.
> Ali
> --- On *Tue, 5/13/08, Matt Chambers /<chambers@imageworks.com>/* wrote:
>     From: Matt Chambers <chambers@imageworks.com>
>     Subject: top N reporting with derby
>     To: derby-user@db.apache.org
>     Date: Tuesday, May 13, 2008, 6:11 PM
>     Hi guys, new to the list.   I'm a new Derby user, just grabbed the 
>     latest version.
>     I have a Tomcat application that sends some statistics to a server for 
>     processing.  The statistics are not mission critical or anything, they 
>     are just nice to have, so if the statistics server goes down, no big 
>     deal.  Its actually never gone down but in case it does, I would like to 
>     spool the updates into a Derby DB.  So I changed the code around a bit 
>     to always store and forward instead of sending directly to the stats 
>     server using Derby but I'm stuck.
>     I have two requirements.
>     1. that if the stats server is down for days that I should be able to 
>     process the spool in small chunks over time when it comes back up.
>     2. each row has to be processed in the order in which i was placed in 
>     the table or else the stats server could drop them anyway.
>     Normally, I would do a SELECT * FROM spool_table ORDER BY date_inserted 
>     ASC LIMIT 100 to grab the oldest entries but Derby can't do limit and 
>     you can't user ORDER BY in sub selects.  So how do I get my data out of 
>     the table in small chunks in the same order it went in?
>     Any ideas?
>     -Matt


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