How does OpenX collect event data?
The collects event-level data, processes the events based on IAB-certified rules and procedures,
and then the Feed Server stores them as GZIP compressed files. Depending on your configuration, the Feed
Server generates files per minute (the default) or per hour, and stores them per event. That is, each minute
or hour, the Feed Server generates and stores up to four files (one for each event type). Each tab-delimited
file contains a header row and is UTF-8-encoded. Each row in the file contains a record for a single event,
where each column contains a piece of collected data. For example, each row of an event file
contains details about a single impression within the hour or minute for which data was collected.