How Prognosis gets the Pathway status information & statistical information and the configuration consideration
Prognosis gathers the Nonstop Pathway statistical (performance) information directly from the Pathway monitor process (PATHMON) by SPI (Subsystem Programmatic Interface).
Status information can be collected either directly from the Pathway monitor using SPI, or via EMS event messages. This choice is controlled from the PATHWAY Configuration at shorter interval than the statistical interval: if the STATUS-INTERVAL is set to 0, then EMS events will be used. Any other value will cause SPI to be used, so the status of monitored pathway can be updated in the PATHWAY record per the configured STATUS-INTERVAL.
This is to provide the most efficient and lowest overhead collection. This splitting of collections intervals enables statistical data, which is usually only reviewed periodically, to be collected on a relatively long interval, controled by INTERVAL setting in PATHWAY configuration.
If STATUS-INTERVAL (0) is specified, TP Manager (Transaction Processing) will monitor EMS events for the configured Pathway systems. If Pathmon is configured with a log destination of $0 (the default EMS collector), using the EVENTFORMAT, STATUS options (e.g. log1, EVENTFORMAT, STATUS), then any state change in a Pathway entity will be immediately visible in the relevant EVENT record. Typically, only the state field in these records will be updated based on events, all other fields will only be updated at every statistics interval. However, if this Pathmon configuration option is used and an EVENTFORMAT, STATUS log destination is NOT configured for a Pathway then the status information will only be updated for that Pathway at every statistics interval, in this case in order to get the pathway status in PATHWAY record the STATUS-INTERVAL needs to be set to a non zero value.