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From Fuzzo <mcucc...@gmail.com>
Subject Re: Embedded Derby and .dat files
Date Wed, 24 Sep 2008 09:03:53 GMT

Many many thanks for your help!

I've tried to do this:
- shut down ActiveMQ (derby checkpoint NOT done)
- opened the db with ij (slow, for recovery mode i suppose, checkpoint DONE)

The final size is now < 5 MB! :)

Now i'm trying to open derby debug query log file (1.17GB...) looking for
queries that may block checkpoint...

See you soon! :)

Knut Anders Hatlen wrote:
> Fuzzo <mcuccato@gmail.com> writes:
>> Thanks for the answer.
>> I've read these instructions in documentation but the Derby instance i
>> use
>> is embedded in ActiveMQ, not in my own application, and i don't wont
>> modify
>> the source code! :)
> You don't need to modify the source code to try it. Just start the ij
> command line tool, connect to the database and invoke the
> statements. That would give a better indication of what the problem is.
>> My questions are:
>> - can i override any ActiveMQ Derby properties to force default
>> checkpoint
>> (after 10MB of logs)?
> The default settings are:
> derby.storage.logSwitchInterval=1048576
> derby.storage.checkpointInterval=10485760
> That is, switch to another log file when the current log file exceeds 1
> MB, and checkpoint when you have 10 MB of log.
>> - why ActiveMQ shoud enable log archiving mode?
> No idea, it's just a guess. Checking if disabling log archiving helps,
> would be a quick way to find out if this is the case.
> Another possibility, also mentioned by others, is that there is a
> long-running transaction or a transaction that the application has
> forgotten to commit or abort. The checkpoint will keep all the log back
> to the start of the oldest active transaction, so that could explain the
> size of the log. In that case, most of the log should be deleted when
> the database is rebooted. Does that happen?
> -- 
> Knut Anders

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