Performance considerations for number sequences in Dynamics AX

Consider the following information about how the configuration of number sequences can affect system performance before you set up number sequences.

Continuous and non-continuous number sequences

Number sequences can be continuous or non-continuous. A continuous number sequence does not skip any numbers, but numbers may not be used sequentially. Numbers from a non-continuous number sequence are used sequentially, but the number sequence may skip numbers. For example, if a user cancels a transaction, a number is generated, but not used. In a continuous number sequence, that number is recycled later. In a non-continuous number sequence, the number is not used.

Continuous number sequences are typically required for external documents, such as purchase orders, sales orders, and invoices. However, continuous number sequences can adversely affect system response times because the system must request a number from the database every time that a new document or record is created.

If you use a non-continuous number sequence, you can enable Preallocation on the Performance FastTab of the Number sequences form. When you specify a quantity of numbers to preallocate, the system selects those numbers and stores them in memory. New numbers are requested from the database only after the preallocated quantity has been used.

Unless there is a regulatory requirement that you use continuous number sequences, we recommend that you use non-continuous number sequences for better performance.

Automatic cleanup of number sequences

In case of a power failure, an application error, or other unexpected failure, the system cannot recycle numbers automatically for continuous number sequences. You can run the cleanup process manually or automatically to recover the lost numbers.

Carefully consider server usage when you plan the cleanup process. We recommend that you perform the cleanup as a batch job during non-peak hours.