Browse Prior Art Database

A Method and Apparatus Achieving High Performance, Reliable Shared HTTP Session State Through Shared Memory

IP.com Disclosure Number: IPCOM000016164D
Original Publication Date: 2002-Aug-15
Included in the Prior Art Database: 2003-Jun-21
Document File: 3 page(s) / 44K

Publishing Venue

IBM

Abstract

This invention describes a method to achieve high performance, yet reliable sharing of HTTP session state among application servers in a cluster, when the servers are all co-located on the same physical node. This invention significantly improves on the current state of the art of propagating session information from one application server to another in web application cluster.

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  A Method and Apparatus Achieving High Performance, Reliable Shared HTTP Session State Through Shared Memory

   This invention describes a method to achieve high performance, yet reliable sharing of HTTP session state among application servers in a cluster, when the servers are all co-located on the same physical node. This invention significantly improves on the current state of the art of propagating session information from one application server to another in web application cluster.

Background

HTTP (HyperText Transfer Protocol) is the underlying data transfer mechanism for web applications. HTTP is a stateless protocol. Therefore, to maintain conversational and application state between client requests session information must be stored and updated on each user. This is a critical function of any web application server.

One feature many major application servers provide is a mechanism to share this user session state between servers. This offers the advantage that if one application server suffers an unexpected failure, user requests can be routed to another application server without the user session and conversational state being lost. The failure is then transparent to the end user.

The methods and mechanisms currently employed to share HTTP session data are complex and inhibit application performance and scalability. Because they address the general case of app servers that may be located on multiple physical nodes, the implementation suffers from several performance and scaling overheads:

     - session state must be serialized on store and deserialized on load. This is known to be expensive

     - session state is stored in a central repository, typically a database. Thus storage and retrieval involves overhead associated...