How do you quantify how much data is coming in for a specific key-value pair?

[campbellj1977]

I am trying to find out just how much data is coming in for a specific key value pair?
So we have only two sourcetypes and I am trying to determine a recent spike in traffic, but I am having a difficult time quantifying where the spike came from using normal field values.

[sundareshr]

Perhaps something like this

index=foo earliest=-2mon@mon | eval mon=strftime(_time, "%b") | chart count over key by mon

[richgalloway]

Maybe this will help

index=foo key=value | eval size=len(_raw) | stats dc(_time) sum(size)