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From Chux <chu...@gmail.com>
Subject Re: When to shut down a database
Date Fri, 11 Apr 2014 04:09:28 GMT
Awesome insights guys, thanks for all your help.

BTW, I could not access the online documentation for some reason. Although
I read somewhere that 64k is the maximum size you can allocate a clob on
embedded mode. Is this correct? I would like to know what the limit is.

variable clob(64 K)

Thanks,
Chux


On Thu, Apr 10, 2014 at 5:32 AM, Dag H. Wanvik <dag.wanvik@oracle.com>wrote:

>
> 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)
>
> Thanks,
> Dag
>
>
>
>
>
>  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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