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A Session Data Management Method for Web Applications

IP.com Disclosure Number: IPCOM000013893D
Original Publication Date: 2000-Aug-01
Included in the Prior Art Database: 2003-Jun-19
Document File: 3 page(s) / 73K

Publishing Venue

IBM

Abstract

Disclosed is a system for efficient session management of Web applications. In particular, it contributes both to the reduction of system memory usage and to ease of use during the navigation among transactional Web applications, which require consistent session management with comparatively large memory requirements in many cases. Accordingly, the disclosed algorithm enables scalable transactional systems using Web infrastructure.

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A Session Data Management Method for Web Applications

    Disclosed is a system for efficient session management of Web applications. In
particular, it contributes both to the reduction of system memory usage and to
ease of use during the navigation among transactional Web applications, which
require consistent session management with comparatively large memory
requirements in many cases. Accordingly, the disclosed algorithm enables scalable
transactional systems using Web infrastructure.

The basic idea consists of (1) watching the access history of URLs which the user
visits by indirectly accessing external URLs, (2) defining hierarchical classes
of URLs, which are used to select an appropriate session management strategy
according to the currently accessed URL, and (3) storing the session data into
different parts of memory with different life times which are determined by the
session management strategy.

When a user starts a session, some session information is stored in the server's
main memory. In the processing, the user may access internal or external URL's
outside of the session-related pages. The user may return to the session soon or
much later or may not return at all. The likelihood of return can be calculated
from the URL class of the currently accessed URL. According to this probability
estimate, the session data is swapped out of the main memory to secondary or
other complementary stores, which have larger capacity but require expensive
costs to access the data. In addition, if the user does not return to the session
within a determined expiration time, the swapped session data will be expired to
release the resources, where the expiration time is also determined based on the
probability of the session being resumed.

Web Application Web Server

Controller

Main memory

Secondary storage

Access watcher

3rd level storage

....

Client

(Browser)

HTTP

HTTP

HTTP

HTTP

(Watchable) Ext. URLs

(Unwatchable) Ext. URLs

....

Figure 1

Figure 1 shows a system diagram related to this disclosure. The Web server
contains the application which performs transactions and requires session
management. Clients connect to the server by using HTTP and display the
information from the server and send the transaction data to the server. The user
may access external URLs which are served by some other Web server during the
transaction. There are two types of external URLs: (1) watchable URLs and (2)
unwatchable URLs. Unwatchable URLs are directly accessed from the client and the
server cannot be aware of the access. In this case, the algorithm treats
unwatchable URLs as greatly lowering the likelihood of session resumption. On the
other hand, watchable URLs are not accessed directly from the client, but
accessed indirectly through the module named access watcher in the server. The
access watcher receives the document from the external server and sends it to the

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client, and reports the user's current URL to the c...