One of the design decisions in RBF is deciding who pays for commitment transactions. It's quite feasible to have two different sets, taking the tx fees from different sides depending on who decides to broadcast.

...and the code for CPFP is already written!

Most important thing is to fix protocols to use better techniques. We're fortunate that RBF is about half the cost of CPFP in most cases.

Indeed.

I'm doing an analysis of covenant dependant layer two protocols right now, which I'm trying to finish ASAP, so I should have a better understanding of the issue soon.

Unfortunately the answer might be that there's no good answer.

How about I change #2 in the “Recommendations” section from:

“Ephemeral outputs should be strongly discouraged due to the above-mentioned miner decentralization risks; support for them should not be added to Bitcoin Core.”

to:

“Existing usage of anchor outputs should be phased out due to the above-mentioned miner decentralization risks; new anchor output support should not be added to new protocols or Bitcoin Core.”

And yes, maybe someone will come up with a way to modify V3 to make it worthwhile. But I agree that without ephemeral anchors the idea doesn't make sense.

Even with ephemeral anchors, for Lightning it's really not _that_ much of an improvement. The second anchors output in anchors channels is redundant. So if we get rid of that, the only savings in ephemeral anchors is the size of the signature/checksig, and that reintroduces tx pinning unless V3 has the tx pinning problem truly fixed.

https://petertodd.org/2023/v3-txs-pinning-vulnerability

All anchor/CPFP schemes have this problem. I singled out ephemeral anchors because they haven't been shipped yet; we should be phasing out anchors entirely whenever possible.

It's true that I could have gone even farther and argued that we shouldn't have CPFP or package relay at all. But I think arguing against CPFP is hopeless; arguing against package relay might be worthwhile still.

A problem is lots of more complex L2 protocols that people are excited about seem to need package relay. But maybe that's not true; I haven't thought enough about those details to be sure.

You know, I've actually had people send me pre-signed txs at multiple fee rates before when they wanted to transfer me large amounts of ₿ and wanted to give me the option of choosing what fee rate to pay.

It's easily automated; the code can do all the hard work behind the scenes.

No matter how often you try to keep fees up to date, the fact is they can change unexpected by the time that you actually need the transaction. This is especially true in cases where nodes go offline unexpected – one of the more common reasons to need to force close in the first place.

It's worse because of the purpose of Phoenix: a single channel end-user wallet where the channel is supposed to contain 100% of the wallet funds to minimize fees and maximize convenience.

With a routing node, keeping around some UTXOs for fee payment isn't as problematic, as you're probably doing more transactions anyway.

Notably, at the moment Phoenix does _not_ keep extra UTXOs around; they do in fact have this problem.

Exactly.

The slope of mempools is very flat, so the opportunity cost of the child is very close to that of the parent.

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Well, read the article. As I explain that's not hard to do in an automated system.

This is in the context of protocols like lightning, so adding RBF is something that code would do automatically.

BTW, I deliberately left a very small off-by-one error in my calculations. See if you can find it!

https://petertodd.org/2023/v3-transactions-review

My last post of the year: V3 Transactions review.

tl;dr: Replace -By-Fee is half the cost, and ephemeral anchor outputs pose a significant mining decentralization risk.

Happy New Year! 🎊

74.1 sat/vB mempool min fee!

It's possible that someone is setting up for an attack on lightning. The current Lightning protocol is kinda broken with respect to fees, as your commitment transaction (and refund transaction) isn't necessarily high fee enough to get propagated.

It's not quite as much of a problem as you'd expect, as many well connected nodes (rg mempool.space) have much bigger mempools. But anyway, lightning needs to get this fixed.

Not using RBF to begin with was a big mistake.

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Yes, that's exactly what I do with donations.

Accepting LN for speeding up transactions makes sense and I'll probably do it at some point. It does require a bunch of code to do well though.

Thanks guys! Between the lightning donations, and a large on chain donation, we've should have enough funds to keep all my OTS calendars running for a few more months.

Thanks!

Right now, it's averaging once every 28 hours. But that does change as feerates go up and down, as the calendars spend approximately a constant amount on fees per day.

If I get mode donations, I can potentially speed that up for better timestamps.

https://geyser.fund/project/opentimestamps

I setup a fundraiser on Geyser for tx fees for the OpenTimestamps calendars. One of them recently ran out entirely, and the other is close to running out. They cost about 100,000sats/week, $40/week, to run at the moment for a transaction every ~28 hours, so I'm hoping the community can chip in.

I do have funding for the server costs. Just need funds for the tx fees.

That benefit is something that a non-censoring pool can easily replicate.

Well I'm Craig Wright.

What do I pay?

Ah, yeah, sorry I misread what you said.

Technically you don't know if they contained PFAS. There are other ways to make paper straws waterproof.

Surfin' Bitcoin in France had decent bamboo(?) straws. I'm sure they're a lot more expensive than paper and bioplastics though.

Actually the EU seems to have significantly better straws than Canada now. I don't know if it's a legal difference. But in the EU I frequently see bioplastic straws that are basically identical to plastic straws, while in Canada you pretty much only seem to get true paper straws that just turn into mush.

Nope. They were talking about dogs their families had lost. Most of which had to be euthanized or otherwise had a vet involved. But one died naturally. Hence the line of questioning, if the vet doesn't report the death who does?

In the US even in places that have dog licensing, the supermajority of people ignore it.