[Objectbridge-developers] AW: [Fwd: Re: ConnectionManager]

[Mahler T. <tho...@it...>]

Hi Satish,

> 
> Hi Thomas,
> 
> I will do that right away. Thank you!!
> 
> I noticed another problem. Basically, if the database is
> down when I do a query using PersistenceBroker, I do not
> get a PersistenceBroker exception. It seems that the SQL
> exceptions are caught and handled but not rethrown. At the
> app layer, It makes it very hard to report errors or do
> any error handling. For example, a broker.getCollectionByQuery
> will return an empty iterator. So, for the app, it seems like
> there are no elements that match the query in db.
> 

In it's early days OJB caught most exceptions. There are still places where
exceptions are not properly reached to the client app.
I will have a code walkthrough to improve this situation.

> Hope my feedback is useful and doesn't sound like whining.

As always: thanks for your carefull observance. Each reported bug will
improve OJB so it's definitely useful!

thanks,

Thomas

> 
> Thank you,
> Satish.
> 
> 
> On Wed, 01 Jan 1997 01:07:56 +0100 Thomas Mahler
> <tho...@ho...> wrote:
> >Hi Satish,
> >sa...@na... wrote:
> >> 
> >> Hi Thomas,
> >> 
> >> I have been noticing that lots of JDBC connections were getting
> >> created for simple queries using the same broker instance.
> >> 
> >> Then I noticed that new ConnectionManager
> >> instances were getting created for each query using the same broker
> >> instance. I inserted some debug statements and I think I might be
> >> seeing a bug.
> >> 
> >> Basically, since the connectionTable is empty for a new 
> ConnectionManager
> >> (created in StatementsForClass), getNewConnection is called in
> >> ConnectionManager. Also curious is why the 
> connectionManager object in
> >> PersistenceBroker was not being used?
> >> 
> >> I haven't had the time to put together a simple case that 
> you can use.
> >> But, if you need, I will do so.
> >> 
> >> Please let me know.
> >> 
> >> If you do have a fix for this, can you mail it to me since 
> I need to get
> >> this software out as soon as possible.
> >> 
> >Yes, this is definitely a bug. Sascha reported it some days ago and I
> >already prepared a fix.
> >As I did a lot of other internal changes in the meantime 
> that won't be
> >compatible to your sources I can't send you the patched files.
> >But fortunately it's not difficult to do:
> >1. provide PersistenceBrokerImpl with a public method
> >getConnectionManager():
> >public ConnectionManager getConnectionManager()
> >{
> >   return m_ConnectionManager;
> >}
> >
> >2. in the StamentsForClass constructor change the line
> > ConnectionManager manager = new ConnectionManager(broker);
> >
> >to:
> >
> > ConnectionManager manager = broker.getConnectionManager();
> > 
> >3. That's it! 
> >
> >> Also, did you get a chance to look at my previous email regarding
> >> mysql wait_timeouts on idle connections and hence you can 
> be left with
> >> stale connections in the pool (the server pool).
> >> 
> >
> >Yes, but it's not easy to simulate this behaviour with instantdb. I
> >assume that the method java.sql.Connection.isClosed() will 
> return true
> >or throws an SQLException in this case.
> >I will write some code that will use isClosed() to check if the
> >connection is still valid and will acquire a fresh one if 
> necessary. The
> >fix will be in the next release. (by the end of the week)
> >
> >HTH,
> >
> >Thomas
> >
> >> Thanks for all your help,
> >> Satish.
> >> 
> >> --
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>


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