Polling requests are supported for clients that require periodic updates for a request. Instead of the client re-submitting the same request on a timer, the request can be registered with the QR to poll. The client registers the request once and receives results asynchronously each time the request executes. The benefits of this are;
- Reduced load on the client: single request to register and then only needs to process results
- Multiple end-clients can share the same request: reduced number of queries hitting the databases
- Supports all one-shot request features: including routing and paging
- New poll requests are only scheduled after the previous poll completes. Meaning slow-running requests aren't queued against an already busy database.
Polling requests by default are uniquely defined by the query, target, frequency and user. This differs from the managed query functionality in the DS_QM process where different users would share the same request. The QR can be configured to support this mode and share requests across users by excluding the user from the uniqueness check.
To enable this mode,
.qr.poll.byUser should be set to
false in the
INSTANCE_CONFIG config parameter override/DEFAULT set for the QR.