# Configuration

By default, you can use two guaranteed queues (TDQ type R) and TSQ (type S) and one reliable queue (TDQ type G) even if Substation ES has not been connected.

You can configure the Substation ES startup to use more than the defaults, depending on the number of CICS applications that write to those queues. If you have a high volume of Guaranteed type messages to deliver or a large volume of data to process, it is recommended that you set the HVT-WORKERS parameter value to the maximum of 10.

For additional information on setting up and configuring Substation ES, see the TIBCO Substation ES Installation manual.

When a transaction links to `SXCQWRIT` the first time, `SXCQWRIT` is allocated to one of the queues. All subsequent links to `SXCQWRIT` by that task use the same allocated queue. A transaction can link to `SXCQWRIT` multiple times, but there is no switching between queues for that transaction (task). For example, if the TDQ `SXQ0` is selected on the first link to `SXCQWRIT`, all further links to `SXCQWRIT` use `SXQ0`. When another task first links to `SXCQWRIT`, `SXCQWRIT` is allocated a different queue. That way, the number of “CICS enqueues” due to tasks with the same TDQ is greatly reduced. Links to `SXCQWTSQ` for the TSQ facility do not have an enqueue problem.

`SXCQWRIT` can handle data lengths and container information of sizes greater than 32 KB. Remember that many large data records occupy huge storage areas and can impact performance. Large records are broken up into multiple Transient Data Records before they are sent to the Substation ES trigger server. User data located in TSQs are still limited to the CICS limitations of 32,767, which is the maximum for a signed halfword. Using containers is far more efficient.

Programs can combine both links to `SXCQWRIT`, `SXCQWTSQ`, and `WRITEQ` to `SXQT` or `SXQG` in them. `SXCQWRTSQ` can handle data lengths and Container information of sizes up to 32,000.

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