Global Connection Pool?

Question

Hello,
Maybe this is not a specific OCCI question, sorry if this is not the best place to post this.
Well, the point is I wanted please an opinion on witch is the best way to optimize (ie, limit the number of) the connections to the server in the following scenario: we have one database, multiple (in the order of hundreds) of clients that use many different applications and keep them open for most of the time (and in fact this is the problem, there are too many connections...);
Most of the applications use the same business-logic component, that makes the connection to the database. I wanted to implement something like a timeout for the idle connections, but Ithink that disconnecting/reconnecting all the time would be slow. Then I came to the topic of a connection pool, but from what I understood a connection pool applies to only one process, right? What I wanted to achieve is something like a "global" connection pool, since all applications use the same component to access the data it just this component needs to be altered.
My idea was then this: create another component (exe) that maintains a connection pool that is shared by many applictions (sure, I would write this in COM/ATL and it has to be a free threaded component); Then when some application needs to query for some data it simply instantiates a connection, uses it and releases it. The only real "operations" we need is query and update/insert of data, so it wouldn't be so difficult to implement a connection and a resultset objetct. Sure, we in this case there would be a constant communication between both applications (via COM), maybe it would slow it down a bit but since our applications are not so "real-time" and the bottleneck resides more in the server I thnk this wouldn't be an issue...
My question is: is this a good idea, is it insane, or there exists another easier-better way to optimize our scenario, ie, reduce the number of connections used by multiple processes?
Thanks,
Tiago Gehring

Answer 1

Hi everbright,
I prefer NOT to make a JDBC connection pool a global resource. After all, if you have several applications on the same Tomcat instance you might not want them all to hit the same database. Better to make it a context-specific thing.
I don't edit the server.xml - ever. I create the context XML in a separate file and deploy it with my WAR file. Tomcat picks it up automatically. Now my apps are nice and self-contained, and I don't have to ask a server admin to modify anything.
Got the DBCP JAR in your WEB-INF/lib?
This URL looks incorrect to me if you're using the Oracle JDBC driver:
jdbc:oracle:thin:[email protected]:1521:DEVI think it should be:
jdbc:oracle:thin:@127.0.0.1:1521:DEVLooks like you're trying to do this in a JSP. Have you tried moving the database code out of the JSP and into a JavaBean, where it belongs? You can test the database connection offline that way. Get it working and then worry about Tomcat.
When I do a JNDI lookup, the Java code looks like this:
    /** Default JNDI lookup name for all data sources */
    public static final String DEFAULT_LOOKUP    = "java:comp/env/jdbc/APIPrototype";
     * Create a DatabaseBroker
     * @param lookup for data source
     * @throws NamingException if the lookup fails
     * @throws SQLException if the connection fails
    public DatabaseBroker(String lookup) throws NamingException, SQLException
        Context context = new InitialContext();
        DataSource ds   = (DataSource)context.lookup(lookup);
        this.connection = ds.getConnection();
        context.close();
    }I know this works, because it's been running in production under Tomcat 4.1.30 connecting to Oracle 9i for over a year.
You can do this.
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