For non-reusable Sequence Generator transformations, Number of Cached Values is set to zero by default, and the Integration Service does not cache values during the session. When the Integration Service does not cache values, it accesses the repository for the current value at the start of a session. The Integration Service then generates values for the sequence. At the end of the session, the Integration Service updates the current value in the repository.

When you set Number of Cached Values greater than zero, the Integration Service caches values during the session. At the start of the session, the Integration Service accesses the repository for the current value, caches the configured number of values, and updates the current value accordingly. If the Integration Service uses all values in the cache, it accesses the repository for the next set of values and updates the current value. At the end of the session, the Integration Service discards any remaining values in the cache.

For non-reusable Sequence Generator transformations, setting Number of Cached Values greater than zero can increase the number of times the Integration Service accesses the repository during the session. It also causes sections of skipped values since unused cached values are discarded at the end of each session.

For example, you configure a Sequence Generator transformation as follows: Number of Cached Values = 50, Current Value = 1, Increment By = 1. When the Integration Service starts the session, it caches 50 values for the session and updates the current value to 50 in the repository. The Integration Service uses values 1 to 39 for the session and discards the unused values, 40 to 49. When the Integration Service runs the session again, it checks the repository for the current value, which is 50. It then caches the next 50 values and updates the current value to 100. During the session, it uses values 50 to 98. The values generated for the two sessions are 1 to 39 and 50 to 98.