Quote from: Andre# on January 25, 2016, 10:52:34 PM

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I have not yet seen a single cryptocurrency that hasn't resorted to dev intervention under circumstances of bloat/flood attack. Whether it is about fees or block size, something has to give in order to stop it or restrain it.

Which flood attack? The couple of "stress tests" that we had last year?

The network is in constant saturation by dust and spam that want to be processed for free or near zero cost. A stress test is just a more focused version of the same issue.

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Near-zero to zero fee txs equals near-zero to zero fee attacks. Attacks which do not have serious economic disincentives betray a broken underlying game theory.

If that's a problem, a minimum fee should be introduced.

It is a problem but we also face political pressure. You can get crucified for doing the right fee with populist bullshit like "ohhh the devs are raising the fees, they want to make BTC expensive for users" crap.

Ethereum, which is hot these days, says, you know Bitcoin is kind of ...idealistic in its approach, we'll just use fees to prevent abuse:

https://github.com/ethereum/wiki/wiki/White-Paper#fees

"Because every transaction published into the blockchain imposes on the network the cost of needing to download and verify it, there is a need for some regulatory mechanism, typically involving transaction fees, to prevent abuse."

Free or nearly free txs = free or nearly free abuse. If you allow that = you are a joke coin that can be attacked by script-kiddies.

In BTC the last line of defense, in absence of serious fees requirement, is the block size.

When you have scaling issues you can't allow abuse like that. Some people are like, who cares, let's make the blockchain a few TBs, make the limit as large as it gets, we can afford hard disks... and we don't even need to run full nodes, we'll all use SPV. Yet, even BTC "competitors" (supposing someone doesn't want to listen to arguments by "core" or "classic") say there is centralization danger when you bloat the blockchain:

https://github.com/ethereum/wiki/wiki/White-Paper#scalability

"Scalability

One common concern about Ethereum is the issue of scalability. Like Bitcoin, Ethereum suffers from the flaw that every transaction needs to be processed by every node in the network. With Bitcoin, the size of the current blockchain rests at about 15 GB, growing by about 1 MB per hour. If the Bitcoin network were to process Visa's 2000 transactions per second, it would grow by 1 MB per three seconds (1 GB per hour, 8 TB per year). Ethereum is likely to suffer a similar growth pattern, worsened by the fact that there will be many applications on top of the Ethereum blockchain instead of just a currency as is the case with Bitcoin, but ameliorated by the fact that Ethereum full nodes need to store just the state instead of the entire blockchain history.

The problem with such a large blockchain size is centralization risk. If the blockchain size increases to, say, 100 TB, then the likely scenario would be that only a very small number of large businesses would run full nodes, with all regular users using light SPV nodes. In such a situation, there arises the potential concern that the full nodes could band together and all agree to cheat in some profitable fashion (eg. change the block reward, give themselves BTC). Light nodes would have no way of detecting this immediately. Of course, at least one honest full node would likely exist, and after a few hours information about the fraud would trickle out through channels like Reddit, but at that point it would be too late: it would be up to the ordinary users to organize an effort to blacklist the given blocks, a massive and likely infeasible coordination problem on a similar scale as that of pulling off a successful 51% attack."

Now note that Ethereum is soaring these days despite "fees" and "more scaling issues" due to all the apps that will be running on top of it. The market says it's the "next big thing". Or that it's a pump & dump. We'll see.

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Let's hope, once we get to 2mb, miners will be more selective with the trash txs.

Will only happen once the subsidy is the same order of magnitude as the sum of fees in a block. As long as the subsidy is very high, you are left to chose from (1) hugely increasing the number of tx or (2) hugely increasing tx fees. For neither there's any demand now.

There's also the BTC price increase factor.

Subsidy of 25 BTCs at 500$ is the same as subsidy of 12.5 BTCs at 1000$.

The first miners mining 50 BTCs were getting paid much less (in usd) than the current miners at 25 BTC. Likewise for fees. ~0.3 BTC in fees today are, let's say ~120-130$, when it used to be ...nothing (in usd terms), even when people were using 0.01 for a fee.

I was thinking that an ideal way to eliminate spam would be for the miners/nodes to agree to not process txs that use a fee lower than 10 cents. We'd probably go down to 200-600kb blocks right away (depending the load) with plenty of room to spare - and probably everything would go in in the first block. But having prices in USD doesn't work in terms of code (which deals with BTC fractions).