 |
 | Home | Contact Us | FAQ | Search & Site Map | Link to Us |
 | Sign In | Join | Other 45 Sites in Network |
Java Forum / General / February 2008connection pooling dilemma
Hi, I wrote an application that interact with a database and first every page like isert_db.jsp delete_db.jsp had the following code: Class.forName((String)session.getAttribute("driver_name")); conn = DriverManager.getConnection((String)session.getAttribute("db_url"), (String)session.getAttribute("username"), (String)session.getAttribute("pwd")) so every time I reloaded the driver and so on... so I learned some concepts to configure Tomcat to use connection pooling to improve my db application and now every page has the following code: Context initContext = new InitialContext(); Context envContext = (Context)initContext.lookup("java:/comp/env"); DataSource ds = (DataSource)envContext.lookup("jdbc/articoli"); conn = ds.getConnection(); but the mystery for me is that the first time I load the page I have a net speed measurement of 200 to 400 ms and then a speed of 10 to 20 ms. But the same I have with no connection pooling! How is possible? May be a JNDI lookup is the problem? How can I set only once the lookup in JNDI and have for every page a DataSource object? > Hi, I wrote an application that interact with a database and first > every page like [quoted text clipped - 12 lines] > > so every time I reloaded the driver and so on... You don't actually reload the driver, nor do you need to call the forName() for the driver more than once in an application. Subsequent calls to load a class that's already loaded through the same class loader do not reload the class. > so I learned some concepts to configure Tomcat to use connection > pooling to improve my db application [quoted text clipped - 9 lines] > and then a speed of 10 to 20 ms. But the same I have with no > connection pooling! How is possible? Do you mean the first time after the application has started in Tomcat? If so, then most likely you are seeing the overhead to translate the JSP into Java and compile it into bytecode. You might see this go away if you pre-compile the JSPs before executing the app. What is the mystery for me is why you have any Java code (a.k.a. "scriptlet") in your JSP at all.  SignatureLew > What is the mystery for me is why you have any Java code (a.k.a. > "scriptlet") in your JSP at all. Absolutely. There is another thread about passing on a "connection" through JSP's which shows similar bad pratices. I recommend all web developers to read and understand MVC, for example from this page http://www.ibm.com/developerworks/library/j-struts/ It's a bit dated but the concept part is pretty clear. Cheers robert >> What is the mystery for me is why you have any Java code (a.k.a. >> "scriptlet") in your JSP at all. [quoted text clipped - 6 lines] > > It's a bit dated but the concept part is pretty clear. <http://en.wikipedia.org/wiki/Model-view-controller> gives a good introduction and a host of links about MVC. The Struts implementation is really the Sun "Model 2" limited MVC model. Full-blown MVC is more complex and useful than that. Java Server Faces (JSF) is a more full-blown MVC implementation. SignatureLew > > Hi, I wrote an application that interact with a database and first > > every page like [quoted text clipped - 43 lines] > -- > Lew in every jsp file I make Context initContext = new InitialContext(); Context envContext = (Context)initContext.lookup("java:/comp/env"); DataSource ds = (DataSource)envContext.lookup("jdbc/articoli"); conn = ds.getConnection(); is there a way to init a DataSource one time only and than reuse it in all my pages? should it improve further on my appl? -- Josh > in every jsp [sic] file I make > [quoted text clipped - 7 lines] > > should it improve further on my appl? Yes, follow Robert Klemme's advice to look into MVC and take all the scriptlet out of your JSPs. This kind of thing is much easier to manage from a plain-ol' Java class. You could init() the DataSource from a static initializer or such. There are also a number of declarative ways to create a DataSource, e.g., via the context.xml of a Tomcat app. SignatureLew >> in every jsp [sic] file I make >> [quoted text clipped - 16 lines] > There are also a number of declarative ways to create a DataSource, > e.g., via the context.xml of a Tomcat app. And of course one can use listeners for various events, namely application startup, shutdown, session creation, destruction, request processing (filters) etc. But IMHO the best way is the declarative as you pointed out. Kind regards robert Free MagazinesGet these publications absolutely FREE for up to 12 months. There are no hidden fees and no obligation. Simply choose a title, complete the application form and submit it. Read more ...
|
Reply to this Message
|
 Sign In
 Join
 My Latest Posts My Monitored Threads My Blog My Photo Gallery My Profile My Homepage Start New Thread Enable EMail Alerts Rate this Thread
|
©2008 Advenet LLC Privacy Policy - Terms of Use
This website includes both content owned or controlled by Advenet as well as content owned or controlled by third parties.