Thanks max for your suggestions,
Yah, there was a connection leak in a mthod, so that leades to system slow
down.
Now it's OK, I am monitoring my application performance ,
then, we are using Resin connection pool class. any more suggestions?
Regards,
Viru
----- Original Message -----
From: "Max Cooper" <[EMAIL PROTECTED]>
To: "Struts Users Mailing List" <[EMAIL PROTECTED]>
Sent: Wednesday, January 14, 2004 4:04 PM
Subject: Re: Database pool full.
> We were using the Oracle connection pool implementation, and it is a
> configurable item on there. There is no config file, so we used a method
> call to set the strategy in that case. I would expect that other pool
> implementations might have different options and different configuration
> procedures. I'm not familiar with the MySQL config, or even if the pool
you
> are using is part of the MySQL driver package (or perhaps the pool is part
> of Resin?). What is the fully-qualified class name of the DataSource class
> you are using?
>
> -Max
>
> ----- Original Message -----
> From: "virupaksha" <[EMAIL PROTECTED]>
> To: "Struts Users Mailing List" <[EMAIL PROTECTED]>
> Sent: Tuesday, January 13, 2004 9:02 PM
> Subject: Re: Database pool full.
>
>
> > 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
> > >
> > >
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> > >
> > >
> >
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> >
>
>
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