AdSense Facts & Fiction Part III: The stats pipeline

Fiction: Site maintenance periods and delays in my AdSense reports mean that data isn’t being recorded properly.

Fact: Although there can sometimes be delays in the stats pipeline, all data is still tracked accurately.

We call the process of tracking your clicks, impressions, and earnings the “stats pipeline.” The stats pipeline runs continuously, reviewing the logs of activity written by our ad serving system, aggregating them, and updating the storage system. So that we can generate these statistics quickly and reliably, without losing any information, the process of aggregating your statistics spans several data centers.

Sometimes in rare cases, the process for aggregating stats can be delayed for several hours. This can happen for a few possible reasons:

• We sometimes make updates to our datacenter to make use of the latest technologies. However, these don’t affect how your clicks are tracked or how much you earn. Depending on the time it takes for the updates to complete, you may notice that stats are delayed by several hours.
  
  
• We have scheduled database down-times, generally on Saturday mornings (Pacific Time). Since the process of aggregating your statistics depends on database data, any such downtime also leads to delay in statistics. I’d recommend reading this Inside AdSense post for more information about these downtimes.
  
  
• On rare occasions, data centers can have unforeseen problems, causing unplanned delay in updating statistics.

These downtimes only delay your statistics -- they don’t impact the actual tracking of your statistics. We make sure that all events are processed exactly once, and we have implemented a number of internally and externally audited verification procedures to ensure that this is the case. Also, events in the aggregation pipeline are processed in a way that’s not specific to a particular publisher, so all of you should get your stats updates at the same time.

When downtimes occur, we work to notify publishers in advance and as quickly as possible using this blog, the AdSense Help Forum, and our Known Issues page. We understand how important it is for you to have up-to-date statistics, and continue to work towards making sure that the delays are kept to a minimum.

Posted by Dia Muthana - Inside AdSense Team