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From "Dag H. Wanvik" <dag.wan...@oracle.com>
Subject Re: When to shut down a database
Date Wed, 09 Apr 2014 21:32:16 GMT

On 09. april 2014 17:51, Rick Hillegas wrote:
> On 4/8/14 2:00 AM, Chux wrote:
>> Hey Dag,
>> Thanks for your insight.
>> I'm using this as an embedded DB in a Java FX desktop application. 
>> This is a dumb question but would you recommend shutting down the 
>> database ever after a transaction? Like after you create a record 
>> then you shut it down after commit.
> Depends on the application. If the database holds some kind of 
> infrequently referenced metadata, so that say, it is only queried or 
> updated once a day, then you could consider an "on demand" model where 
> the database is booted for each query/update, then the query results 
> are returned, then the database is shut down so that it doesn't 
> consume any resources. The big extra cost of an "on demand" database 
> would be this:  query/update time would be substantially longer since 
> every query/update involves booting the database, compiling the 
> query/update, and gracefully closing the database; that cost is on top 
> of the steady-state cost of running a pre-compiled query/update.
In such a scenario one might want to shut down the engine, too, not just 
the database.
Note that shutting down the database will resources, but if the engine 
is still running, one can further release resources by shutting that 
down as well.

Cf. http://db.apache.org/derby/docs/10.10/devguide/tdevdvlp20349.html 
(engine shutdown)
and http://db.apache.org/derby/docs/10.10/devguide/tdevdvlp40464.html 
(shutdown database)


> Hope this helps,
> -Rick
>> Best,
>> Chux
>> On Tue, Apr 8, 2014 at 12:32 AM, Dag H. Wanvik <dag.wanvik@oracle.com 
>> <mailto:dag.wanvik@oracle.com>> wrote:
>>     On 06. april 2014 21:02, George Toma wrote:
>>>     Hi Chux,
>>>     In my opinion  the example from  app.  referred at commit the
>>>     transaction OR close the connection ( a connection could be
>>>     transacted too ), and not to shutdown the db. If the business
>>>     rule specifies that the db. needs to be shutdown when the app. is
>>>     shutdown, then so be it.
>>>     Normally the db is not shutdown, not even when the app is down.
>>     This is true for a client/server application. For use with
>>     embedded Derby, one would normally close down the database (and
>>     the database engine) before exiting the application. If one
>>     neglects to do so,
>>     one would see longer start-up times as Dyre indicated.
>>     Thanks,
>>     Dag
>>>     Cheers,
>>>     George
>>>     On Sunday, April 6, 2014 7:14 PM, Chux <chux18@gmail.com>
>>>     <mailto:chux18@gmail.com> wrote:
>>>     Hello guys,
>>>     I read in a sample app that you've got to shutdown a database. I
>>>     was just confused if you need to shut it down on every connection
>>>     transaction or just shut it down on application close, in my case
>>>     a desktop applicaiton.
>>>     Best,
>>>     Chux

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