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Scheduling Servers
You can control when Ingres Replicator propagates changes to the target databases. If it is not critical to have the CDDS synchronized, you can turn on the servers at slow or no usage times. The main benefit of this strategy is that it conserves processing capacity at critical times; Ingres Replicator consumes resources.
You control replication timing through the servers. If the Replicator Server for a given CDDS is started and active, it is continually propagating changes to the target databases. If the Replicator Server is stopped or started but quiet, changes to the CDDS accumulate in the distribution queue until the Replicator Server is started or activated.
You can use the following methods to schedule Ingres Replicator by starting the replication cycle:
At specific times using the -SGL flag
At specific times using the -QIT flag and raising an event from an application
At given intervals using the -QIT and -EVT flags
Note:  To stop a server to perform maintenance on your system, see the online help topic Status Page [Performance Monitor window, Replication branch] for details. You can also stop servers in a terminal monitor or through your own customized shut down script by issuing the correct event to the server. For more information, see Database Events.
-SGL Flag--Run Replication Once
The -SGL flag configures the server to process its replication queues once before shutting down. You can schedule the replication with your operating system’s job scheduling system—cron under UNIX, at on Windows, submit on VMS.
Place the -SGL flag in the server’s runrepl.opt file.
-QIT Flag--Run Server in Quiet Mode
The -QIT flag starts the Replicator Server in quiet mode.
You can schedule Replicator Server activity with database events by using the -QIT flag setting, and use an Ingres application or script to raise a dd_go_server[n] database event at specific times, where n is the number of the Replicator Server you want to start.
-EVTn Flag--Use Event Timeout
You can use the event timeout flag, -EVTn, to affect server activity. The way the -EVTn flag affects server scheduling depends on several factors. The most common scenarios for using the -EVTn flag to schedule servers are:
Replicator Server with the -NQT flag set
The -EVTn flag controls the duration of the replication cycle in an idle database. On a relatively active database, -EVTn has little effect.
Replicator Server with the -QIT flag set
The -EVTn flag specifies that the Replicator Server reads the distribution queue only every n seconds.
Note:  This configuration can cause significant backlogs because the Replicator Server does not take into account database activity or how large the backup is.
Last modified date: 11/28/2023