Latency is the interval value, expressed in seconds, between the flushing of stale buffers. Latency interval is an option that is exclusively used by the Stream operator.
In normal operations (without latency), the Stream operator reads data from the data stream until its buffer is full, then it writes all buffered rows to the Teradata Database. The data is written to the Teradata Database only when the buffer is full or when a checkpoint is taken. However, a latency interval (for example, set to 5400 seconds) causes the following:
- The Stream operator reads data from the data stream, and empties its buffer, writing the contents to the Teradata Database every 90 minutes (5400 seconds) regardless of whether it is full.
- If the buffer fills up within the time period (in this case, 90 minutes), it writes to the Teradata Database as it would during normal operation.
To set the latency interval, use the following syntax:
tbuild -l <LatencyInterval> -f <filename>
The value used for the latency interval must be a non-zero unsigned integer. The guiding factor is how stale you are willing to allow data to be.
For example, to run a continual load script with a latency interval of two hours, enter:
tbuild -l 7200 -f continualload