Dear Max,
Yah, this problem occures after visiting some pages,
to use #1 strategy, whether I need to do any changes in configuration or is
there any other way?
Thanks for your suggestions & immediate response,
Regards,
viru
----- Original Message -----
From: "Max Cooper" <[EMAIL PROTECTED]>
To: "Struts Users Mailing List" <[EMAIL PROTECTED]>
Sent: Wednesday, January 14, 2004 12:30 PM
Subject: Re: Database pool full.
> My guess is that you have a connection leak somewhere. Does this problem
> start occurring immediately, or does it only show up after visiting a
number
> of pages in the site?
>
> Various db pools have different ways of dealing with no connections being
> available. Often, you can configure which strategy to use. Here are 3
> different strategies:
>
> 1. Wait until a connection becomes available.
> 2. Fail if no connections are available (i.e. return null or throw an
> exception).
> 3. Grow the pool temporarily if there are no free connections.
>
> It is clear from the errors you are getting that your pool is currently
> using strategy #2. I like #1 the best, because it is less likely that
> requests will fail under load. But, you must be sure that you don't have
any
> connection leaks, because the app will eventually hang if you have
> connection leaks and use strategy #1. Strategy #3 works, but you can run
> still run out of connections in the database itself, so it can start to
act
> like strategy #2. This is one aspect of connection pooling that important
to
> consider when developing web apps.
>
> But, it seems likely that you have leaks somewhere. Some of your requests
> are probably not returning their connections to the pool. It could be that
> you have exceptions that are being thrown and not releasing the
connection,
> or it could just be that you have non-exception logic paths that don't
> return the connections. Some combination of code reviews, debugging, etc.
is
> needed to track them down.
>
> Another thing to watch out for is requests that require more than 1
> simultaneous connection. For instance, consider the situation where you
have
> a pool of 30 connections, 15 request handler threads, and a request that
> requires 3 connections. If 15 of those requests come in at once, and each
> request handler thread grabs 2 connections, you will have deadlock as all
> the request handler threads wait forever for a third db connection to
become
> available (assuming you are using pooling strategy #1 above). The solution
> to this problem is to make sure that you don't have any requests that
> require more than one simultaneous connection, or at least that your db
> connection pool has enough connections to survive a flood of connection
> hungry requests (e.g. have a pool of 45 connections in the example
scenario
> described above -- 3 conn/req * 15 threads = 45 connections in the pool).
> This may seem unlikely, but it is a problem I have faced in a production
> system (and it wasn't easy to track down!). Another lister here suggested
a
> good technique for ensuring that none of your requests require more than 1
> simultaneous connection -- test your app with a pool of 1 connections.
>
> -Max
>
> ----- Original Message -----
> From: "virupaksha" <[EMAIL PROTECTED]>
> To: "Struts Users Mailing List" <[EMAIL PROTECTED]>
> Sent: Tuesday, January 13, 2004 7:14 PM
> Subject: Database pool full.
>
>
> Dear All,
>
> I am developing an application on resin-2.1.9 web server.
> Connection to MYSQL Database is using JNDI. JNDI connection code is
written
> in a class called DBService.
> I am instantiating DBService class where ever i need database connection
and
> getting connection using getConnection() method.
>
> when user start working on application, i m getting following errors,
>
> Class:DBService. Method:getConnection() cann't open connection with full
> database pool(30)
> Class:MonthReport. Method:SelectReportDetailNull() cann't open connection
> with full database pool(30)
>
> it sounds like database pool is full, Whether i need to increase the pool
> size or optimize code in DBService database connection class.
>
> for your reference below code performs database connection.
>
> --------------------------------------------------------------
> public Connection getConnection()
> {
> java.sql.Connection con = null;
> javax.sql.DataSource ds=null;
>
> try{
>
> Context initCtx = new InitialContext();
> Context envCtx = (Context) initCtx.lookup("java:comp/env");
> ds= (DataSource)envCtx.lookup("jdbc/training");
> con = ds.getConnection();
>
> }catch(Exception e){
> System.out.println("Class : DBService, Method :
> getConnection()"+e.getMessage());
> }
> return con;
>
> }//end of getConnection method
> -------------------------------------------------------------------------
>
> Your advice will be great help to optimize my application.
>
> Thanks in advance.
>
> Regards,
> Viru
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: [EMAIL PROTECTED]
> For additional commands, e-mail: [EMAIL PROTECTED]
>
>
---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
