NAME

ResourcePool::BigPicture - ResourcePool introduction

DESCRIPTION

The ResourcePool package consists of two major parts:

• ResourcePool

• LoadBalancer

ResourcePool

The ResourcePool is used to manage a pool of persistent connections (or more generally "resources"). Every resource in a pool is exactly equivalent to the others since all of them are created through the same factory.

If you want to make a pool of different resources (e.g. connections to different databases) you have to use the ResourcePool::LoadBalancer.

The ResourcePool uses two other classes to operate:

ResourcePool::Factory

used to create resources

ResourcePool::Resource

used as wrapper to implement a unique interface to all resources

To create a ResourcePool you need a ResourcePool::Factory which is able to create the ResourcePool::Resource's you want to use. The ResourcePool will then use this factory to create ResourcePool::Resource objects as required.

The ResourcePool::Resource itself creates the finally interesting objects like DBI or Net::LDAP and provides a standard way to perform the common operations required by ResourcePool to work with this resource.

The ResourcePool::Factory and ResourcePool::Resource classes are base classes to inherit the specialized classes for your resource from. The classes to handle DBI and Net::LDAP resources are included in the distribution.

After creating a ResourcePool you can use the get() method to obtain a resource. The get() method will return the DBI or Net::LDAP object which can be used as usually. Afterwards you have to hand the resource back into the pool by calling the free() method.

Please have a look to the ResourcePool documentation for further details.

ResourcePool::LoadBalancer

A ResourcePool::LoadBalancer can be used to configure a failover and/or loadbalancing behavior for ResourcePool users.

To construct a ResourcePool::LoadBalancer you need one or more ResourcePools. After construction a ResourcePool::LoadBalancer behaves like a ResourcePool, so you can call the get() method to obtain a resource.

The ResourcePool::LoadBalancer can be configured to use a different ResourcePool every time you call the get() method. The ResourcePool::LoadBalancer can also detect a problem with a ResourcePool (e.g. because the related server is down) and will hide such problems from you.

There are currently three "Policies" which change the way the ResourcePool::LoadBalancer uses the configured resources:

• RoundRobin

• LeastUsage

• FallBack

Learn More

You should have the big picture of ResourcePool and ResourcePool::LoadBalancer now, time to go into the details at the ResourcePool and ResourcePool::LoadBalancer documentation. If you loose track of all these modules consult the ResourcePool::UML diagram.

To learn more about how to implement your own resource extensions have a look to the ResourcePool::ExtensionGuide.

SEE ALSO

ResourcePool, ResourcePool::LoadBalancer, ResourcePool::UML

AUTHOR

    Copyright (C) 2002 by Markus Winand <mws@fatalmind.com>

    This program is free software; you can redistribute it and/or
    modify it under the same terms as Perl itself.