There's clearly a 3 hour periodicity of txn volume.
Now, I'm aware that Geth nodes have a parameter
--txpool.lifetime which is set default to 3 hours. But this doesn't entirely explain the pattern. If each txn has a lifetime of 3 hours, we should see a smooth pattern in the chart (assuming there's a relatively uniform distribution re: txn creation).
I can't think of a good reason for the sharp drop-off every ~3 hours. It seems reasonable to think it's somehow related to the Geth txpool lifetime parameter, but beyond that I'm stumped.
Anyone have any good guesses?