I think it’s a clear upgrade to SIP-001 as well!
I’m going to boil down the above discussion into a few topics and then comment.
We plan to update SIP-007 with a discussion on discounted mining. I think “free mining” is a potentially misleading term for this because the discount is in the 10-20% range given no. of slots and the probability of the discount being 90% or whatever is negligible.
A miner’s main motivation to mine should be the STX coinbase, transaction fees (in STX), and Clarity contract fees (in STX). This decision to mine or not mine needs to be made by the miner for the vast majority of the blocks (where the miner does not have an address) and the miner will decide to mine if it’s profitable to do so.
No miner will mine at a loss, it’s about how much profit can a miner make. It’s a local decision that every miner makes, a miner will not even know if someone else is engaging in discounted mining or not.
If a miner decides that it only makes sense to mine in blocks where she has a payout addresses then that will likely result in sporadic mining where say that miner is participating only in a small subset of blocks.
First, I think the miner does not have the right incentives to participate in sporadic mining. The STX coinbase is not a guarantee but a probability. If you mine sporadically then you are potentially hurting your chances to get the STX coinbase vs mining regularly.
Secondly, you can make it harder for miners to participate in sporadic mining. You can introduce a minimum participation window. For example, if you don’t participate in at least 10 consecutive blocks as a miner then you don’t qualify for the STX coinbase at all. This takes the 10-20% discount to a 1-2% discount and can make it even smaller by increasing the size of the minimum participation window.
Interestingly, an earlier version of STX mining had a window and we got rid of it due to some potential unintended consequences. It might be worth exploring if a modification of a sliding window in the form of a “minimum participation threshold” makes sense.
Thanks for the discussion around discounted mining! It definitely opens interesting discussions and design tradeoffs.