Why was this transaction not included in a block?

[420]

could you tell me why this transaction is not confirmed yet

https://blockchain.info/address/1PMM8TC4NowMnMZronmLp4fEns8cYxC1v6

mt. red, ozcoin and btc guild have all solved a block since this and have not included it

Looks like no transaction fees were paid, is that the reason?

[1713559542]

1713559542

[1713559542]

1713559542

[1713559542]

1713559542

[DannyHamilton]

How come miners get to determine what transactions are included in blocks?

Because that is the purpose for having miners.  That is how bitcoin is designed.  Someone needs to perform a proof-of-work, and create blocks.  In bitcoin we call those people "miners".

For instance a pool can say not to include transactions that haven't paid a fee, is that right?

Yes that is correct.  They can use any conditions they want for determining which transactions to include.

[420]

How come miners get to determine what transactions are included in blocks?

Because that is the purpose for having miners.  That is how bitcoin is designed.  Someone needs to perform a proof-of-work, and create blocks.  In bitcoin we call those people "miners".

For instance a pool can say not to include transactions that haven't paid a fee, is that right?

Yes that is correct.  They can use any conditions they want for determining which transactions to include.

so if government were to spend $1 Billion to fuck the bitcoin system they could get the best miners and hardware that would only solve blocks if they included a transaction fee of a specific special number that they give and design people that they wanted to use the bitcoin system

I see that as a possible way to censorship

I assume there's always a way to check what fee's included so they could just have a specific program to determine what the fee would be and if we can't guess that program and they have banks using that program, without it being leaked they could block all bitcoin transactions they don't like for every block they're solving

[jgarzik]

so if government were to spend $1 Billion to fuck the bitcoin system they could get the best miners and hardware that would only solve blocks if they included a transaction fee of a specific special number that they give and design people that they wanted to use the bitcoin system

Sure.  But...

1) There are plenty of cheaper, easier attacks that would disrupt the bitcoin system anyway.

2) You could just as easily spend $100 million to destroy the market value of bitcoins, by manipulating the free market.

3) The community would want to continue, and so, everyone would agree on a new algorithm, rendering all that expensive hardware useless.

There are plenty of reasons why mining attacks cost far more than other, more realistic attacks.

[420]

Great. Okay could you tell me why this transaction is not confirmed yet

https://blockchain.info/address/1PMM8TC4NowMnMZronmLp4fEns8cYxC1v6

mt. red, ozcoin and btc guild have all solved a block since this and have not included it

[DannyHamilton]

Great. Okay could you tell me why this transaction is not confirmed yet

https://blockchain.info/address/1PMM8TC4NowMnMZronmLp4fEns8cYxC1v6

mt. red, ozcoin and btc guild have all solved a block since this and have not included it

I haven't looked at recent blocks, but it is possible that either:

• There are enough transactions with fees to fill the blocks so your transaction, being lower priority, will have to wait until there are less transactions to confirm
• or, the miners/pools that have solved the recent blocks only include transactions with fees

Note that the "Relayed by" column at blockchain.info doesn't necessarily indicate the miner/pool that "solved" the block.  That is just the first place that blockchain.info heard about the new block.  It is entirely possible for someone to solve a block, have that block relayed from themselves to a mining pool, then from there to another mining pool, and finally relayed to blockchain.info.  So while it may be an indication of who is likely to have solved the block, it isn't certain.

[420]

Okay now I'm quite confused. is there a soft maximum number of transactions included into a block?

And is my transaction even valid if it's listed on blockchain.info but has not had a confirmation yet, if it was a 'double spend' for example it wouldn't even be listed on there right?

[DannyHamilton]

so if government were to spend $1 Billion to fuck the bitcoin system they could get the best miners and hardware that would only solve blocks . . .

Yep, that is how it works.  If a government were to decide to spend enough money to get more then 50% of all the hashing power in the entire bitcoin network, then they would be the ONLY miner to solve any blocks any more, and they could pick and choose which transactions to include.  They could even choose to mine ONLY empty blocks, refusing to include ANY transactions from the network and all and in doing so completely shut down all bitcoin transaction processing for so long as they continue to run their equipment and maintain more than 50% of the hashing power of the entire network.

[DannyHamilton]

Okay now I'm quite confused. is there a soft maximum number of transactions included into a block?

And is my transaction even valid if it's listed on blockchain.info but has not had a confirmation yet, if it was a 'double spend' for example it wouldn't even be listed on there right?

Unless it is a transaction for a significantly large amount of bitcoin, a double spend is unlikely (though not impossible).  If I'm wrong, hopefully someone will correct me, but from what I've heard, I believe it is possible (though VERY unlikely) for an unconfirmed transaction to show up on blockchain.info and still be a double spend attempt.  I think it's even possible (though extremely unlikely) for a transaction to be in a block with 1 confirmation and still turn out to be rolled back as a double spend.

[420]

Okay now I'm quite confused. is there a soft maximum number of transactions included into a block?

And is my transaction even valid if it's listed on blockchain.info but has not had a confirmation yet, if it was a 'double spend' for example it wouldn't even be listed on there right?

Unless it is a transaction for a significantly large amount of bitcoin, a double spend is unlikely (though not impossible).  If I'm wrong, hopefully someone will correct me, but from what I've heard, I believe it is possible (though VERY unlikely) for an unconfirmed transaction to show up on blockchain.info and still be a double spend attempt.  I think it's even possible (though extremely unlikely) for a transaction to be in a block with 1 confirmation and still turn out to be rolled back as a double spend.

wow, never heard of one getting a confirmation and being a double spend. then no wonder exchanges wait for 6 confirmations

that doesn't make sense unless a powerful miner was solving the block and trying to doublespend at the same time

[DannyHamilton]

Okay now I'm quite confused. is there a soft maximum number of transactions included into a block? . . .

The last I heard the blocksize limit was 1 megabyte.  From what I heard, this should be large enough for approximately 2,400 average sized transactions.

[DannyHamilton]

. . . And is my transaction even valid if it's listed on blockchain.info but has not had a confirmation yet, if it was a 'double spend' for example it wouldn't even be listed on there right?

. . . I think it's even possible (though extremely unlikely) for a transaction to be in a block with 1 confirmation and still turn out to be rolled back as a double spend.

wow, never heard of one getting a confirmation and being a double spend. then no wonder exchanges wait for 6 confirmations

that doesn't make sense unless a powerful miner was solving the block and trying to doublespend at the same time

That is one way for it to occur. Like I said, it is extremely unlikely, but if 2 miners each relay a block at approximately the same time, and one miner includes the transaction while another doesn't, then the miner who solves the next block will determine which of the 2 relayed blocks is the legitimate one.  If that miner solving the next block chooses the block that doesn't have the original transaction and instead includes a double spent output in a different transaction, then the first block that had the original transaction vanishes from the current blockchain and the double spent transaction becomes the legitimate one.

[DannyHamilton]

I'm always surprised when I come across someone who has been active enough on bitcointalk.org to have over 1,000 posts, and yet has somehow managed to avoid learning the basics of how bitcoin works.

[MoonShadow]

Okay now I'm quite confused. is there a soft maximum number of transactions included into a block?

There is currently a hard data size limit for a block at one MB, and a soft data size limit for all transactions that do not pay the minimum fee of roughly 10% of that, or about 100KB.  Since the average transaction is about 1.5 KB, it'd only take about 70 free and low fee transactions to hit that soft limit.  Eventually, though, such transactions do make it in.

And is my transaction even valid if it's listed on blockchain.info but has not had a confirmation yet, if it was a 'double spend' for example it wouldn't even be listed on there right?

Blockchain.info can't really know if your transaction is part of a double spend attempt or not, because such conflicts are sovled by a race of sorts.  When a transaction is broadcast to the network, it is received, checked for validity, and forwarded to all that node's peers.  If any node has already seen a transaction that spends particular inputs, any other transaction that it sees afterwards that attempt to spend those same inputs will be invalid, and will not be forwarded.  So what happens is the two competing transactions will move across the p2p network trying to capture as much of the network as possible before they meet at a front.  Once a block is solved, whichever of the two transactions that particular node saw first will be included, and the other becomes forever invalid.  Once that block is accepted by the part of the network that saw the losing transaction first, the losing transaction is droped from their transaction queues altogether.  So under such conditions, the transaction that hits the p2p network first has the advantage.  Right now, the edge to edge propogatin time for the entire network is only about 10 seconds, so it's a very small window of opprotunity.

[MoonShadow]

Looks like it was included in a block.

[DannyHamilton]

Looks like it was included in a block.

Yep, looks like it only took about 45 minutes or so.

[420]

now all a sudden it shows 8 confirmations, does it speed it up after 1st confirmation? people are more likely to include it then or what? or that is all it takes to get the ball rolling

or did blockchain have an error it didn't show me it was confirmed when it was

[DeathAndTaxes]

It is only included in 1 block.  The 2nd and 3rd ... and 8th confirmation simply mean more blocks have been found AFTER the block containing your tx.  Your tx, its fee (or lack of fee) has absolutely no effect on the 2nd confirmation onward. 

The fact that it got 8 confirmations "quickly" simply means 7 more blocks were found "quickly" after the block containing your tx.

[420]

It is only included in 1 block.  The 2nd and 3rd ... and 8th confirmation simply mean more blocks have been found AFTER the block containing your tx.  Your tx, its fee (or lack of fee) has absolutely no effect on the 2nd confirmation onward. 

The fact that it got 8 confirmations "quickly" simply means 7 more blocks were found "quickly" after the block containing your tx.

So then is it wrong someone said it's possible a double spend could get 1 confirmation?

[Anon136]

Okay now I'm quite confused. is there a soft maximum number of transactions included into a block? . . .

The last I heard the blocksize limit was 1 megabyte.  From what I heard, this should be large enough for approximately 2,400 average sized transactions.

so what happens if bitcoin becomes so popular that 100 or 1000 or 100,000 times as many transactions as we see now begin to take place in a given amount of time? would the devs just have to change that cap from 1 mb to something larger? or is the system capable of self adjusting?