With the release of SQList version 8, it is now possible to run multiple instances of SQList on a single installation. This new features allows for a remarkable boost in parallelism and replication performance.
Important: to run multiple instances you will need a licence with this feature enabled. Instances are charges separately.
This article explains how to run multiple instances of SQList on a single installation.
1. Check that you licence allows multiple instances to be run
By default, SQList allows you to run it on a single instance which is called "(Default)". To check whether you can execute multiple instances, select the "Licence status" tab in SQList Manager and check the licence setting named MaxNumberOfInstances in the right-hand panel which indicates how many instances you are allowed to run on your current licence.
The screenshot below show a 30 day Trial licence of SQList that allows up to 3 instances to be run.
2. Spread your replications across instances
Each replication is assigned to an instance and a single instance can be assigned to multiple replications.
You can assign an instance to a replication in the last step of a replication configuration, where the name of the replication is also assigned. For existing replications, simply edit the replication and at the last step assign the instance.
A new dropdown is now available that you can use to assign an instance to the replication.
When an instance is assigned for the first time, the associated Windows Service is registered; the service appears in the Windows Services list as "AxioWorks SQList Service" followed by the instance name. Note that the "(Default)" instance does not append a suffix.
Assigned instances are visible in the Replication list in SQList Manager.
3. Starting and stopping SQList
In the "Service Monitor" panel in SQList Manager there are now two buttons to control the execution of SQList, one to start all instances and one to stop them.
Note that it is currently not possible to start or stop individual instances from SQList Manager, the "Start SQList" will start all non-running instances and the "Stop SQList" will stop all running instances.
However, individual instances can we started and stopped directly in Windows Services. The screenshot below show instance "Instance2" being the only instance running.
4. Monitoring running instances
Running instances can be monitored in the "Service Monitor" panel in which a column indicating the running instance has been added to both the replication monitor (top half of the screen) and the log monitor (bottom half).
The log monitor has also been enhanced with more detailed information about the messages (double-click a message to open the property window).
Note that each instance creates its own set of "system tables" in their assigned destination databases, prefixed with the instance names (with the exception of the "(Default)" instance).
The names of tables corresponding to replicated SharePoint lists are not affected instead.
5. Conclusion
Every instance operates as an independent process, unaffected by other processes in any way. As a result, lengthy replications running on one instance will not impede the progress of replications on other instances. This feature enables the fine-tuning of replications based on priority and workload, ensuring optimal performance.
There are no restrictions on the number of instances that can be executed, except for the limitations of the hosting machine.