Performance

Database Size

Database size depends on the number of records or files in the database. The size determines the overall storage requirement for the database. Most database management systems can handle relatively small databases of less than 100 million bytes; fewer can manage terabyte-sizeddatabases.

Today, companies are trimming the size of their databases to maintain good performance and reduce costs. According to a project manager at Kennametal, "Our overweight database was months away from crashing due to exceeding our production disk-space capacity." The company was able to save about $700,000 in additional hardware and storage costs by trimming its database.

Number of Concurrent Users

The number of simultaneous users that can access the contents of the database is also an important factor. Clearly, a database that is used by a large workgroup must be able to support a number of concurrent users; if it cannot, then the efficiency of the members will be lowered. The term scalability is sometimes used to describe how well a database performs as the size of the database or the number of concurrent users is increased. A highly scalable database management system is desirable to provide flexibility. Unfortunately, many companies make a poor DBMS choice in this regard and then later are forced to convert to a new DBMS whenthe original does not meet expectations.

Performance

How fast the database is able to update records can be the most important performance criterion for some organizations. Credit card and airline companies, for example, must have database systems that can update customer records and check credit or make a plane reservation in seconds, not minutes. Other applications, such as payroll, can be done once a week or less frequently and do not require immediate processing. If an application demands immediacy, it also demands rapid recovery facilities in the event that the computer system shuts down temporarily. Other performance considerations include the number of concurren users that can be supported and the amount of memory that is required to execute the database management program. One database was able to process 1,184,893 transactions per minute on average, setting a new world record for speed. Organizations often undergo performance tuning to increase database speed and storage efficiency. Performance tuning involves making adjustments to the database to enhance overall performance.

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