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From Rick Hillegas <rick.hille...@oracle.com>
Subject Re: When to shut down a database
Date Fri, 11 Apr 2014 13:41:39 GMT
Hi Chux,

The default (and maximum) size for a CLOB is 2,147,483,647 characters. 
See http://db.apache.org/derby/docs/10.10/ref/rrefclob.html. If you have 
found a place in the documentation where some other limit is stated, 
could you let us know where that is so that we can correct that 
misleading statement?

Thanks,
-Rick

On 4/10/14 9:09 PM, Chux wrote:
> 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 
> <mailto: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>
>             <mailto: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>>
>                 <mailto: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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