he emergence of the Internet as an application development platform has displaced some technologies and given others a new lease on life. The online transaction processing monitor is an example of the latter. OLTP has been used in mainframe and high-end client-server environments for years. TP monitors help preserve data integrity, ensuring that information from multiple data sources is processed quickly and accurately. TP monitors bring load balancing, message control, and application recovery to the Web environment.
Enter the World Wide Web. As companies start transacting their core business over the Web, they want to ensure data integrity, and they don't want to create a whole new system to do it. Banks such as Wells Fargo and Bank of America offer online banking to customers. Utilities and credit-card companies want to offer Web services as well. BMG Entertainment in New York wants to sell CDs on the Web, and Data Broadcasting Corp. in San Mateo,
Calif., wants to sell stocks.
Until now, the chosen method of database access via the Web has been Common Gateway Interface (CGI) scripts written in the Perl programming language. This has proved to be a less-than-optimal solution, because Perl scripts are not high performance or highly scalable compared with the client-server environment. The use of CGI can also entail significant reengineering to make data available on the Web, because the CGI gateway works only on the Web server-it can't go out to other machines. The Web server can become bogged down with requests when a lot of users hit the system.
"CGI is a very inefficient way to deal with a large number of clients," says Chris Horak, director of product marketing for BEA Systems Inc. in Sunnyvale, Calif., developer of the Tuxedo TP monitor. The solution from the TP monitor vendors, such as BEA and IBM's Transarc Corp. in Pittsburgh, which makes the Encina transaction monitor, has been to produce middleware that can forward Web requests to TP m
onitors, which in turn send the request to one or many application servers. By doing this, corporate developers can offer a more scalable interface to their existing systems without having to perform significant reengineering.
This process or middleware layer is what offers the bandwidth and scalability that CGI-based programs don't offer, says Charles McGuinness, director of technical marketing at Prolifics, developer of the Prolifics 3.0 development tool for building enterprise-scale transactional database applications. The middleware also acts as a funnel, keeping open a few connections to application servers or databases rather than giving a direct connection to every user making a query. This eases the crunch on the database server by offloading processing.
The need for TP monitors stems from the unpredictable nature of Internet traffic. "The Web has made application usage unpredictable," says Frank Vafier, president of Prolifics, in New York. Prolifics licensed the Tuxedo TP monitor from BEA Sys
tems for inclusion in Prolifics 3.0. Internet use "gives these systems spikes of usage that they have to be architected to support. You have no choice but to build these things with a TP monitor," he says.
RockPort Trade Systems Inc., a Gloucester, Mass., developer of global supply-chain-management software, used the Prolifics tool to build its RockBlocks client-server network application. It's being modified to support Web queries. "The Web all of a sudden adds a lot more transactions and queries to our database environment. It puts a strain that we've never seen," says Jack Zakarian, chief technology officer at RockPort.
Prolifics provided RockPort with a complete solution-programming language, TP monitor, and Web connectivity support. "It's easier to maintain and train people, rather than have a bunch of pieces you have to integrate and try to keep in sync," says Zakarian.
Distrib
uted Load
The second benefit of using a TP monitor is that administrators can distribute computing and data over multiple servers. Under the CGI-based Web database structure, the database had to reside on the same server because the Web server and the load could not be distributed. Nor could data in other, remote databases be searched.
Nortel Technology in Ottawa, the IT arm of Northern Telecom, chose a TP monitor for its Web applications so it could multiplex database connections and offload query processing. "It allows the Web server to act as just an HTML server rather than as an application server," says Sean Boers, a software designer at Nortel Technology. His group is developing a number of intranet applications in Jam, Prolifics' Java-based application development environment.
TP monitors lighten the burden on Web servers, too, says Boers. He's not sure how many more users his company's system can handle, but he has the option of adding transaction servers as necessary for increased lo
ad. An added benefit: Transaction servers can be located in different locations. None of this could be done in CGI without a lot of headaches, Boers says.
But one analyst says using a TP monitor, which costs in the six-figure range, is overkill for what is being done on the Web. "They're trying to dig a little hole with a backhoe," says Ted Schadler, a software analyst with Forrester Research in Cambridge, Mass. "Half the people who've installed Tuxedo are using it for a messaging backbone to bring together applications, rather than using it to do things you need a TP monitor for, like two-phased commits and audits and logging."
However, Schadler acknowledges that cheaper and less-complex alternatives are still in the future. Microsoft's Transaction Server-code named Viper-is good for department-level transactions, but not for supporting the traffic crush from Internet users. The Object Management Group's Object Transaction Services standard hasn't been finalized, and vendors of object request brokers
, such as Iona Technology Ltd. in Dublin, Ireland, and Visigenic Software Inc. in San Mateo, Calif., are doing their own implementations before the release of the formal specification.
Users need a new generation of tools to build robust Internet applications, says Schadler. He recommends that developers consider application servers, such as NetDynamics' NetDynamics tool, SilverStream Software's Web Application Platform, and Kiva Software's Kiva Enterprise Server. These comprehensive development environments support high-volume transactions using application partitioning and load balancing.
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he emergence of the Internet as an application development platform has displaced some technologies and given others a new lease on life. The online transaction processing monitor is an example of the latter. OLTP has been used in mainframe and high-end client-server environments for years. TP monitors help preserve data integrity, ensuring that information from multiple data sources is processed quickly and accurately. TP monitors bring load balancing, message control, and application recovery to the Web environment.
