Nice animated graphs, weex.

Here's a plot of the mempool size for the past day, for comparison to normal levels.  

http://i.imgur.com/tEPlmCr.png

Also note the spike in required fees, brought about by the higher-than-average fees being paid by the spammed transactions.

Live graphs are available here.

Thanks Jorge for the mini-analysis.  I'm the developer of that site.

The plot you linked is a dynamic one; so here is the static plot of that time interval:

http://i.imgur.com/dVzx0BL.png

And the same graph, but scaled for viewing of the tx byterate:

http://i.imgur.com/MEfBHg7.png

Some things to note (I should have added this on the site, ideally):

1. The tx byterate estimation is done using a exponential moving average, with a halflife of 1 hour.

2. The capacity byterate is given by

blockrate * expected max block size

where expectation is taken over the mining pools; estimates for pool max block size policies can be found here.

Just a comment on the following:


I don't think you can say that - that would be like saying, queues are never a problem as long as utilization is < 1 (which of course is required for stability). But long queues do in fact develop when utilization is < 1, due to variability in service / arrival times (re: bitcoin, the dominant source of variability is in inter-block times).

As long as there are queues, fee tension will be present, as mempool transactions are largely prioritised by feerate. Empirically, we are observing periods of fee tension (i.e. busy periods, when pools' max block size is reached) quite often these days.

Otherwise I like this perspective on the block size problem (even though I can't really comment on the proposed solution), in particular the observation that in the short term transaction demand is inelastic. (Upon further thought, however, proponents of increasing block size would say that the inelastic demand problem doesn't really apply if the block size cap is sufficiently higher than the average transaction rate.)