Re: [Classifier4j-devel] Update Word Probability Break Down

[Peter L. <pe...@le...>]

Hi Matt,

         There are many open source implementations of JDBC connection pooling, there's no need to
implement our own. eg:

http://jakarta.apache.org/commons/dbcp/
http://sourceforge.net/projects/c3p0/

         Nick? I know you like to keep your dependencies down :)

Regards,
Peter

> After I reconstituted dbTest.java (attached) to open and close the database 
> connection each iteration as updateWordProbability does, the exact same error 
> occurs at exactly the same time (around 3900 iterations).  This is without 
> using any classifier4J code.
> 
> So, now the questions arise...
> 
> 1) Is this problem still somehow isolated to my configuration.  I would love 
> it someone could reproduce this problem.
> 
> 2) is this behavior somehow by design and if so, is there a setting to be 
> altered.
> 
> 3) if this problem is not isolated to my environment, how has gone 
> undetected.  Seems doubtful that no one has attempted to classify teachMatch() 
> a 4000+ word document, or maybe it is possible.
> 
> 4) if this problem is not limited to my configuration, what is to be done 
> about it.  It was suggested that I "might" want to implement connection 
> pooling in my own code.  It seems to me, in light of this issue, classifier4J 
> needs to implement connection pooling internally?  Is this possible? 
> 
> 5) Meanwhile, any hints on implementing connection pooling in conjunction with 
> classifier4J would be greatly appreciated.
> 
> I really wish I had some idea what I was talking about...
> 
> Matt Collier
> RemoteIT
> mco...@my...
> 877-4-NEW-LAN
> 
> 
> -----Original Message-----
> From: "Matt Collier" <MCo...@my...>
> To: cla...@li...
> Date: Wed, 12 Nov 2003 11:07:04 -0600
> Subject: Re: [Classifier4j-devel] Update Word Probability Break Down
> 
> > Is it correct to say that our database connection is getting setup and torn 
> > down each time updateWordProbability is called?
> > 
> > From what I gather, this is not good practice to begin with.  Opening and 
> > closing a database connection 60-80 times per second has to be taxing.  As I 
> > understand it, this is where connection pooling comes in.
> > 
> > I wonder if JDBC might have some protection mechanism build in for clients 
> > that go haywire.  Perhaps it closes connections for processes that open and 
> > close connections too many times.  Maybe it just fails.
> > 
> > AH HA!  This is a diffence between my dbTest.java and connect.java.  I am not
> > connecting and disconnecting on each record.  I will rebuild this to test.
> > 
> > I don't know the first thing about how to implement connection pooling to 
> > begin with, much less in this conext, but I guess that's what I'll start 
> > working on!
> > 
> > BTW, I've narrowed the error to the call to connectionManager.getConnection()
> > in updateWordProbability.  I have increased the exception handling to produce
> > the following information:
> > 
> > SQLState: 08S01
> > VendorError: 0
> > NextException: null
> > 
> > SQLState 08S01 = mySQL error ER_BAD_HOST_ERROR according to:
> > 
> > http://mysql.mirror.trueserver.nl/doc/en/Error-returns.html
> >