Distributed Transactions, SQL, and Application Servers
By Ken North
As recently as 1997, some pundits had forecast that the Internet would cause the demise of SQL. That assertion was based on the argument that SQL was unable to scale up to support armies of users, very large databases (VLDBs), or high-volume online transaction processing (OLTP). If you examine world-class transaction processing (TP) systems and e-commerce sites, you'll quickly recognize that the argument lacks credibility. When you survey megasites such as Amazon.com, you find SQL databases. If you read Winter Corporation's 1998 VLDB Survey (see "
Online"), you'll see that several of the world's largest OLTP systems run with SQL databases. Organizations having the largest SQL databases for OLTP include UPS, Chase Manhattan Bank, Metromail, and TELSTRA (Australia's telecommunications provider). TELSTRA processes 300 transactions per second using a 4.3-terabyte database. UPS's massive OLTP system uses a DB2 database containing 324 million rows, or 16,800GB of data.
TP programs are used in business to prevent breakdowns in data integrity. An example is a funds transfer that partially completes by taking money out of one account without putting it in another. TP programs provide a safeguard against failures that create anomalies and data integrity problems. Commerce and business-related software are heavy users of databases and transactions.
