Orchestrator can benefit from a setup based on a read-only replica of its read-write operational database, with the main purpose of improving performance. Some read-only workloads are directed towards the read-only replica, so as to optimize write-replica consumption. This allows data to be read and loaded faster, which, in turn, ensures the performance of your system.

As a result of this implementation, a slight delay between the write and read actions might occur. This is to be expected, and has no impact on data becoming available.

Retrieving queue items

This can be enabled through the Features.Queues.QueryUseReadOnlyReplica parameter.
Please be aware that, when the workflow tries to retrieve queue items as soon as they were added, they might not be displayed instantly, as there is a slight millisecond-level delay between the operational database (where the item is written) and the replica (which is called for reading the item).
You can, however, avoid this by using the Get transaction item activity instead of Get queue items, since the former includes the queue item in its response.

Orchestrator monitoring

Can be enabled through the Monitoring.UseReadOnlyReplica parameter.
The same mechanism applies when retrieving data used to display your monitoring views.