Understand Countdown global process settings

Note: For information on overriding default configuration settings, see Modify configuration settings.

The global settings for AVEVA Pipeline Operations for Liquids applications are set in the AVEVA Pipeline Operations for Liquids configuration JSON file located at %DNAInstallRoot%\RealTime\config\Settings\LMS.RealTime.Json. The Countdown settings content is within the "LMS" > "Countdown" section.

The settings from this file are installed as part of the AVEVA Pipeline Operations for Liquids installation process. You will not normally need to change these settings. If you do need to change this file, the RealTime service must be restarted for the changes to take effect.

The following example details the default settings in the file:

"Countdown": {

"CheckIn": true,

"CriticalProcess": false,

"RestartProcessOnUnexpectedExit": false,

"CheckinTimeout": 60,

"CheckinSleepInterval": 15,

"StartUpDelay": 60

"PubSubReceiveQueueSize": 50000

}

}

Where:

• "CheckIn" is a true/false value indicating whether or not Countdown should check into the RealTime Process Monitor at startup.

• "CriticalProcess" is a true/false value indicating whether or not Countdown should check into RealTime Process Monitor as a critical process (only applicable when CheckIn is true).

• "RestartProcessOnUnexpectedExit" is a true/false value indicating whether or not Countdown should restart and check into RealTime Process Monitor as a process to restart on unexpected exit (only applicable when CheckIn is true).

• "CheckinTimeout" is an integer value indicating the maximum number of seconds between check-ins before the Countdown process is declared dead (only applicable when CheckIn is true).

• "CheckinSleepInterval" is an integer value indicating the number of seconds between each attempted check-in by Countdown (only applicable when CheckIn is true).

• "StartupDelay" is an integer value indicating the number of seconds that the primary processing loop of Countdown will wait before beginning operations.

• "PubSubReceiveQueueSize" is an integer value indicating the size of the PubSub receive queue. The size of this queue is a function of the number of configured objects for each type and the number of topics associated with these types. The size can be calculated as follows:

  S =

  ((Number of countdowncfg records x 3) + (Number of multistate records x 1) + (Number of batchXfer records x 6) +

  (Number of rate records x 3) + (Number of tank records x 6) + (Number of virtualflowcomputer records x 3)) x 1.10

  PubSubReceiveQueueSize = S rounded up to the nearest 10,000

Notes: AVEVA recommends that the value of PubSubReceiveQueueSize be tested by performing a few failover scenarios to ensure connectivity between the standby and hot servers. An insufficient queue size will cause the system to disconnect from PubSub. A disconnected state is not recoverable and will trigger a failover to the standby server. When the disconnection from PubSub occurs, it is accompanied by the following log error message:

ERROR - Application Countdown (pid N) has been declared too slow.

If the above error log message persists after using the calculated value for PubSubReceiveQueueSize, multiply the calculated value by a factor of two, restart RealTime and retest the same failover scenarios. You may need to perform a few iterations of adjusting the value and testing the failover scenarios until no errors occur.

It is recommended that you perform this test again whenever a large number of assets are added to the system.