Reporter is missing data when processing a very small log
Flushing Reporter Log Data
When running a Reporter evaluation you may notice when processing a very small log with specific known data, not all of the log data is seen. This is because Reporter is designed to continually process large volumes of log data, and as a result the session data in the report lags slightly behind the actual log data being processed. When processing a specific, small set of logs, the administrator must manually force a data flush in order to see all of the session data. This is true of other counter data as well, but is much less obvious because other data is typically flushed more often. For example, it is very common for the last 5 seconds of log data to still be in the buffer and be missing from reports after processing log data.
In general, if you want to process a specific set of logs and it is imperative that you see all log data reflected in a report, force a full flush by either restarting the Reporter service or unloading and reloading the profile. Otherwise, for continuity between log files, reporter assumes it is just waiting for the next log file, and holds on to some log data so that arbitrary log breaks do not affect session data or page view combining.