incrediBILL - 7:22 pm on Jan 19, 2011 (gmt 0)

Whoops!

I was wrong, if you use a single page like "google_adsense_alt_ads.html" the browser caches it so even a single occurrence in the log file can mean NO ADS RUNNING.

To solve this problem, make a unique page per ad block such as:
google_adsense_alt_ads_skyscraper.html
google_adsense_alt_ads_linkunits.html
google_adsense_alt_ads_bigbox.html

etc.

Then change the command above to be:

grep "google_adsense_alt_ads_" -i access_log | awk '{print $11}' | sort | uniq -c

Leaving it open ended will catch all the variations.

This way you can easily see which individual units didn't display, or all.

Just when you think you have it under control you find something overlooked :)

Can't wait to share the story that started this after I'm sure it's fixed.