Configuring Fast Communication Manager

The Fast Communication Manager (FCM) is an internal component of DB2 that plays a crucial role in inter-partition communication and parallel execution. On non-partitioned databases, it is activated if the INTRA_PARALLEL database manager parameter is set to YES. Depending on the database partition configuration, it can use shared memory or socket communication. The first case is applicable if we have logical partitioning (every partition is located on the same server); socket communication is used if we have separated servers or physical partitions. It being an important performance factor, you should be careful with setting FCM-related parameters.

Getting ready

An important component of FCM is the FCM buffer. An FCM buffer is actually a structure that holds data that is going to be passed between agents. The communication ports used by FCM are defined in the /etc/services file. For example, in our case, we have defined a maximum of four logical ports...