Mining pools publishing lists of transactions

[leijurv]

Why don't the 5 biggest mining pools (ghash.io, btc guild, eligius, slush and bitminter) publish what transactions they are including in the block they're mining? (The transactions that will be included in the next block if they mine it) That way you could be relatively sure that your transaction will (probably) be included in the next block. If you're a merchant, you can be reasonably sure there won't be a double spend, if all 5 of them include the correct transaction. (If some of them have a conflicting transaction you know that a double spend was attempted). This seems like a really useful feature. Why don't they provide it? I know that they publish the block headers to connected miners, but not the list of transactions.

[Trongersoll]

I can see reasons for them not doing this. One would be that they probably don't know. When the pools are looking for a block, they are, I believe, looking at many differnt combinations of transactions at the same time across their supporting miners. Another, they don't know what they will use next until they see what was used by the successfully found blocks.

These things are done by computers, there isn't some pool operater sitting there deciding which one to use.

[grue]

they don't do that because:

• it's going to cause extra server load from thousands of people refreshing every 30 seconds to see whether their 0.0001 BTC no fee transaction went through
• it's extra work that does not benefit their customers (miners)
• it doesn't generate revenue

[DeathAndTaxes]

I can see reasons for them not doing this. One would be that they probably don't know. When the pools are looking for a block, they are, I believe, looking at many differnt combinations of transactions at the same time across their supporting miners. Another, they don't know what they will use next until they see what was used by the successfully found blocks.

None of that is correct.

These things are done by computers, there isn't some pool operater sitting there deciding which one to use.

Wouldn't that imply it is easier and fully automated for a pool to know and report what tx are in the current working block?

[DeathAndTaxes]

they don't do that because:

• it's going to cause extra server load from thousands of people refreshing every 30 seconds to see whether their 0.0001 BTC no fee transaction went through
• it's extra work that does not benefit their customers (miners)
• it doesn't generate revenue

Offer it as a paid service.  People pay for Level 2 quotes I am sure merchants would pay for "pool visibility".

[leijurv]

I can see reasons for them not doing this. One would be that they probably don't know. When the pools are looking for a block, they are, I believe, looking at many differnt combinations of transactions at the same time across their supporting miners.

I suppose they are using many different combinations. That doesn't really matter for most people because in the combinations, they're probably swapping out low-priority transactions (with low fees) because they really want to maximize the fees they get.

Another, they don't know what they will use next until they see what was used by the successfully found blocks.

What? This is only for the next block, the transactions in the block that they are trying to mine.

they don't do that because:

• it's going to cause extra server load from thousands of people refreshing every 30 seconds to see whether their 0.0001 BTC no fee transaction went through
• it's extra work that does not benefit their customers (miners)
• it doesn't generate revenue

Offer it as a paid service.  People pay for Level 2 quotes I am sure merchants would pay for "pool visibility".

Yes. Merchants would pay a few bitcents per block to see what transactions will be included. Then they'll know with a pretty high degree of certainty if someone even attempted a double-spend. If merchants could see this for the mining pools compromising ~80-90% of the hashing power of the network, then they could even accept payments with even 0 confirmations, because for a conflicting transaction to be mined (the main worry for merchants) would require most of the solo-miners (comprising ~15% of the network) to collude and include the conflicting transaction. Since I'm pretty sure that the non-pool 15% is pretty fragmented (no one person has control of more than 0.5% of the network), you'd need to get a lot of solo miners to include the conflicting transaction.