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When more than one FairCom Server was run on a Unix system, the shared memory keys used by different servers could have the same value, which prevented connections to the servers. In addition, it was possible for unrelated applications to collide with default keys generated by FairCom Server.
To address this key collision, it is possible for an administrator to specify specific shared memory keys for ISAM and SQL shared memory communication protocols ensuring the keys do not match existing keys already in use on the system.
FairCom Server configuration options are available to directly specify a shared memory key. SQL and ISAM each require separate shared memory support:
SHMEM_KEY_ISAM <isam_shared_memory_key>
SHMEM_KEY_SQL <sql_shared_memory_key>
Shared memory key values can be specified in either decimal or hexadecimal format. For example:
; Set shared memory key for ISAM connections to the specified decimal value:
SHMEM_KEY_ISAM 12345
; Set shared memory key for ISAM connections to the specified hexadecimal value:
SHMEM_KEY_ISAM 0xabcd
These server configuration options support specifying an environment variable, whose value is substituted for the configuration option value when the server starts up. For example, if the environment variable MY_ISAM_KEY is set to a numeric value such as 12345 or 0xabcdef before starting the server process, then the following option can be specified in the server configuration file to use this environment variable value for the SHMEM_KEY_ISAM configuration option value:
SHMEM_KEY_ISAM %MY_ISAM_KEY%
