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From Oyvind.Bakk...@Sun.COM
Subject Re: I need some advice to choose database for an upcomming job
Date Mon, 07 Nov 2005 12:17:28 GMT
Daniel John Debrunner wrote:
> Oyvind.Bakksjo@Sun.COM wrote:
> 
> 
>>Note A: You may want to create and use more than one connection to
>>increase performance if you have many simultaneous requests.
> 
> 
> I would not recommend a single connection for any simultaneous requests.
> 
> 
>>Note B: If you're running with autocommit OFF, you should definately not
>>use the same connection object in multiple simultaneous requests (either
>>use synchronization or create multiple connections).
> 
> 
> This is true even with automcommit on. Multiple threads using the same
> connection with ResultSets will mess with each other, as per the JDBC
> sprc. An executeQuery by one thread will close any ResultSet any other
> thread is processing.
> 
> If you are running Derby embedded then the cost of creating a connection
> per request will be much lower than traditional client server databases,
> and most likely will be a small fraction of the cost of the query or update.

That's true, as long as the database is not booted & shut down with each 
request. That was the case in the "prototype integration" described in 
the referred article.

As long as the database is booted & shut down only in the context 
listener class, it should be fine to create new embedded connections 
with each request.

-- 
Oyvind Bakksjo
Sun Microsystems, Database Technology Group
Trondheim, Norway
http://weblogs.java.net/blog/bakksjo/

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