Database Files

The database resides in the message server folder on the Logical Host. The database consists of a number of database files called segments. A segment is a disk-space store that is memory-mapped on the server. The segments act together to form the equivalent of a sequential database. By default, these files are named stcms*.dbs.

The JMS IQ Manager creates four segments in the database when it starts up initially. The default size of a segment is 8 MBytes on Windows and 16 MBytes on UNIX. The JMS IQ Manager creates as many segments as necessary. Before running your Java CAPS Project, it is important to set the segment size to a larger value than the largest transaction the JMS IQ Manager may need to process, since the JMS IQ Manager cannot accommodate a transaction that is larger than the segment size.

The transaction size is the sum of the sizes of the individual messages involved.

You can configure such properties as database filenames, segment size, and the maximum and minimum number of segments created. For more information, refer to Segment Properties.