Topic: Block Size soft-limit maxing out this AM 6/3/13 - page 2. (Read 6176 times)

question for Jeff Garzik or misterbigg, or any defenders of artificially constrained blocks...
is this considered to be of no real concern?

3000+ transactions waiting
$100 in fees alone to be mined (Incentive not yet enough?)
Pending size of 2.37Mb = 90 minutes at 250Kb blocks!

http://blockchain.info/unconfirmed-transactions

Everybody saw what happened when Mt Gox was unable to process transactions in their system as quickly as they were being initiated, right?

You are missing the point. If Bitcoin can only support a million people, no amount of fee will allow it to support a million and one. Limiting block space to keep the fee up is like limiting food production to keep food prices up.

The hard block limit is no different than, for example, a government-imposed food production ban to support farmers. Even farmers who want to produce more food, because they earn more that way (compare with miners earning more by ignoring the limit), cannot because of the restriction. And the people who eat, starve. Nobody benefits from this scenario.

What we should be doing instead is letting the market decide the fee. Make block space unlimited, but expensive to produce. There are a few ways of accomplishing this:

1. Pay-for-space. For every kB a block takes up, the miner loses a certain amount of reward. Even malicious miners lose this reward, as it doesn't go to anyone. The reward could be adjusted like difficulty, or some other method, to allow growth in the network. This ensures there is no limit to block size if it becomes necessary, and ensures the blockchain will not be too big, as there is significant financial cost in doing so.

2. Prioritize-small-blocks. Currently, block length and orphans are determined through sum of block difficulty. This could, through a hard fork, add a risk to making bigger blocks, as they are more likely to be orphaned. If transaction fees are high enough that this risk is manageable, then the block sizes will increase. The only problem with this approach is the increased threat of a 51% attack by someone mining empty blocks. Hopefully the financial incentive of mining full blocks will counteract that.

People complain about how low the transaction fees are. I like to pose them this question below. If this isn't an argument for killing the block size limit, I don't know what is.


There are so many elegant solutions to this block size problem. Keeping the current limit isn't one of them.

Other way to look at it is if you can't be bothered to include a decent fee then you don't really care about when will your transaction be included.

Higher fees is not the solution to this. At present the miners are already massively profiting; their electricity costs are far below the income from solving a block, even for GPU miners, and even if you include depreciation of equipment.

Quick estimate:  4xGPU = $1000, lifetime 12 months, equals a cost of roughly $0.02 per block.

Current difficulty, roughly 4 million, meaning you need to perform 17x10^15 = 17 PetaHashes PH to solve a block. The card will perform 1.5MH/J, meaning you need about 10GJ of energy to perform all those 17 PH.  10 GJ of energy is equal to about 2700 kWh which, at $0.20 each, will cost maybe $550.  The 25BTC reward from the block, right now, gets you over $1000. Leaving a profit of $1000 - $550 - $0.02 = $449.98 per block solved, which you can expect roughly every 150 days (17 PH per block divided by 1.3 GH/sec for the 4 GPUs). Data from https://en.bitcoin.it/wiki/Mining_hardware_comparison

Naturally a clever miner will have 40 GPUs instead of 4, and earn those $449.98 every 15 days instead. Or maybe 400 GPUs.

Of course, a clever *and* lucky miner, will be running an ASIC, say, a BFL minirig, churning out 1.5TH/s (no consumer versions online yet, supposedly), solving perhaps 7 blocks per day but requiring only 17 MJ per block solved, roughly 5 kWh or $1.00. Depreciation of the minirig ($35000) over, say, 36 months will cost $0.22 per block.  So the BFL minirig miner would profit by $1000 - $1.00 - $0.22 = $998.78 per block solved, or roughly $7,000 per day. How bad!

I did ignore the fact that the difficulty will increase in these estimates. If I made any other glaring mistakes, please point them out.

Typical Tx fees per block are now maybe 0.3BTC. So even if that were to go up by a factor of 10, it would still be far less significant than the block reward.

Bearing in mind that the purpose of the transaction fee is to attract miners and secure the network, it should be clear that increasing fees at this time is not going to achieve its designated purpose. The block reward is already much more than sufficient for that. And it certainly won't create more block space. What it *will* do, however, is alienate users.

Insisting on higher fees because miners have a monopoly on a commodity (block space) with an artificially imposed scarcity... well, really just sounds like the big boys club all over again, doesn't it?

Yes! Concisely put.

This is of course, patent nonsense.

Bitcoin's merit is in its decentralization. If the block size stays at its current level, it stands that only the current level of users can use it. The ~1000000 people who use Bitcoin today will serve as the centralizers of tomorrow's Bitcoin. That's still 7000 people per centralized authority.

Block size limit should be removed entirely and replaced with a "prefer-small-block" system.

Who let the shill for Paypal/Visa into the Bitcoin forum?

Exactly. If you want your transactions processed quickly, attach a nice healthy fee with them. If you can't be bothered to include a decent fee then your transaction deserves to be left behind.

Bitcoin's design has miners serving the role of filters. For the majority of flooding attacks, the planned deterrant of transaction fees work pretty well: an attacker would need to waste a bit of their own money to successfully flood. Unfortunately, SD is the exception that has managed to make use of social engineering to get someone else to cover the expense of getting around the fees. Not only that, but because SD's enablers are gamblers, they are throwing their money away anyway so are willing to ignore fees higher than rational users of Bitcoin who just want to send money. Thankfully, detecting and blocking SD specifically is also fairly easy.

LOL who is the midget?

i have read some of the threads about SD generating tons of 'spam' tx and it seems clear that it is difficult to prevent this sort of flooding.

are there any countermeasures planned for such flooding attacks?

ok, fine. As long as miners are aware and can increase easily when it's considered necessary...

Bet at least most of those blocks were by pools neglecting their duty to filter out flooding attacks.

The "soft" limit is set by each miner.

When I mined using vanilla, unmodified bitcoind + p2pool, it was a simple configuration setting to change the limit to 900k.

My first block was over 400k.

Soft limit "maxing out" is a non-event.

Even with higher fees, if blocks are full then transactions will be left behind.


How does the 250 limit go away? I thought is up to each miner.

If a miner fills a block higher than 250Kb and less than 1Mg will it be rejected by the other miners?
EDIT - Ok just saw an 487Kb transaction

http://blockchain.info/charts/transaction-fees-usd?showDataPoints=false×pan=&show_header=true&daysAverageString=7&scale=0&address=

Yes, so obvious that higher fees haven't started happening already...

It is very good. Now people will start including larger fees with their transactions.

http://blockchain.info/unconfirmed-transactions

This is an unusually high number. (Call me whatever, but I keep an eye on this as it is the beating heart of Bitcoin).
In conjunction with saturated blocks - it is unique and not good...

Where do you find this info on pending transactions?

Is this the first time this "maxing out" happens?