Use flush latency to run a session in real time. Flush latency determines how often the Integration Service flushes data from the source. For example, if you set the flush latency to 10 seconds, the Integration Service flushes data from the source every 10 seconds.
For change data from a PowerExchange change data capture source, the flush latency interval is determined by the flush latency and the unit of work (UOW) count attributes. For more information, see
PowerExchange Interfaces for PowerCenter
The Integration Service uses the following process when it reads data from a real-time source and the session is configured with flush latency:
The Integration Service reads data from the source.
The flush latency interval begins when the Integration Service reads the first message from the source.
At the end of the flush latency interval, the Integration Service stops reading data from the source.
The Integration Service processes messages and writes them to the target.
The Integration Service reads from the source again until it reaches the next flush latency interval.
Configure flush latency in seconds. The default value is zero, which indicates that the flush latency is disabled and the session does not run in real time.
Configure the flush latency interval depending on how dynamic the data is and how quickly users need to access the data. If data is outdated quickly, such as financial trading information, then configure a lower flush latency interval so the target tables are updated as close as possible to when the changes occurred. For example, users need updated financial data every few minutes. However, they need updated customer address changes only once a day. Configure a lower flush latency interval for financial data and a higher flush latency interval for address changes.
Use the following rules and guidelines when you configure flush latency:
The Integration Service does not buffer messages longer than the flush latency interval.
The lower you set the flush latency interval, the more frequently the Integration Service commits messages to the target.
If you use a low flush latency interval, the session can consume more system resources.
If you configure a commit interval, then a combination of the flush latency and the commit interval determines when the data is committed to the target.