Product Documentation

FairCom ISAM for C

Previous Topic

Next Topic

I/O Management


In some environments where FairCom uses native operating system threads, it may be possible to allow FairCom DB to use more than one file handle or I/O channel for a given file or index. If the operating environment supports this, it can significantly improve the file access performance of FairCom DB. For instance, if two users read from and write to the same file at the same time, the FairCom Server can improve the performance of the system by using multiple handles into the same file, up to #define NUMCHANEL, presently set at 2.

Once established using the ctDUPCHANEL file mode, the operation is transparent to the client. FairCom Server manages it automatically.

Specify ctDUPCHANEL for files that have heavy simultaneously use by multiple users. The benefits may decrease if a large number of files are open with this mode. In addition, with a large number of files and a restricted number of file handles available from the operating environment, you may not see an improvement.