Appendix F: CMX Replication Server transfer queue tuning

When the Hot and Standby servers take a long time to synchronize and the following messages appear repeatedly in the %DNADataRoot%\RealTime\Log\cmxrepsvr.log file, you will need to increase the value of the DEF_XFRQ_STALE_UPDATELENGTH key to improve the synchronization timing (refer to Appendix A: CMX replication configuration settings):

022-03-11 09:11:07.388 [TID=0xff8] DEBUGLOG: Transfer Queue: Queue is stale. Disabling all subscriptions, deleting all updates {C:\Agents\C2\_work\267\s\Service\source\Replication\CmxRepSvr\transferq_service_support.cpp:97}

2022-03-11 09:11:07.388 [TID=0xff8] DEBUGLOG: Transfer Queue: TIME: elapsed 127, minimum required 1500 {C:\Agents\C2\_work\267\s\Service\source\Replication\CmxRepSvr\transferq_service_support.cpp:99}

2022-03-11 09:11:07.389 [TID=0xff8] DEBUGLOG: Transfer Queue: UPDATES: current # 420288386, maximum allowed 409715200

It is unlikely that you will need to change the value of the DEF_XFRQ_STALE_UPDATELENGTH key for small-sized systems. However, for a large-sized system consisting of three RealTime load-balanced systems with a total database size of over 1,000,000 points, change the value to 509715200 (refer to Improve the synchronization time of the Hot and Standby servers). AVEVA has found that this value improves the Hot and Standby synchronization time. You can also apply this setting to other large-sized systems with different system topologies.