Is blockexplorer's total bitcoins in existance accurate? - page 2.

John Tobey

hero member

Activity: 481

Merit: 529

Quote from: piuk on September 27, 2011, 05:01:02 PM

Are you sure it's not a problem with your database theymos? The other block explorers report the 50 BTC generated ok

Indeed two pairs of blocks contain duplicate coinbase transactions, as I confirmed by querying Abe's database. I believe some miner failed to configure a new output address for each block, and when it solved two blocks with the same "reward" (50 BTC in this case) and the same coinbase script (collision in the "extra nonce" field and lack of other distinguishing data), this resulted in bitwise identical transactions. I would consider this a bug in the program that assembles blocks for the miner.

Abe currently deducts for lower-than-deserved rewards but fails to notice duplicate transactions. Abe also deducts when a coin goes to the public key hash consisting of all zero bits, which can not be reclaimed if our assumptions about crypto strength hold.

dree12

legendary

Activity: 1246

Merit: 1077

Quote from: Maged on September 27, 2011, 06:32:11 PM

Quote from: piuk on September 27, 2011, 05:01:02 PM

Are you sure it's not a problem with your database theymos? The other block explorers report the 50 BTC generated ok

That's because the 50 BTC was, indeed, generated ok. It's just not possible to spend the duplicate transactions since the Bitcoin client considers the two transactions to be one and the same.

How exactly is it possible for two transactions to be the same? Or is this only possible with "Generated" transactions?

Maged

legendary

Activity: 1204

Merit: 1015

Quote from: piuk on September 27, 2011, 05:01:02 PM

Are you sure it's not a problem with your database theymos? The other block explorers report the 50 BTC generated ok

That's because the 50 BTC was, indeed, generated ok. It's just not possible to spend the duplicate transactions since the Bitcoin client considers the two transactions to be one and the same.

piuk

hero member

Activity: 910

Merit: 1005

Quote from: theymos on September 24, 2011, 06:50:35 PM

Quote from: maaku

@theymos: that's an awfully round number. Are there 4 blocks that didn't generate bitcoins at all?

At least two blocks didn't generate any BTC:
http://blockexplorer.com/block/00000000000a4d0a398161ffc163c503763b1f4360639393e0e4c8e300e0caec
http://blockexplorer.com/block/00000000000743f190a18c5577a3c2d2a1f610ae9601ac046a38084ccb7cd721

I'm not sure where where the other BTC was lost. My current database structure doesn't allow me to easily get the particulars. It's also possible my calculation was incorrect.

Are you sure it's not a problem with your database theymos? The other block explorers report the 50 BTC generated ok

http://pi.uk.com/bitcoin/block-index/92507/00000000000a4d0a398161ffc163c503763b1f4360639393e0e4c8e300e0caec

http://pident.artefact2.com/block/00000000000a4d0a398161ffc163c503763b1f4360639393e0e4c8e300e0caec

http://abe.john-edwin-tobey.org/block/00000000000a4d0a398161ffc163c503763b1f4360639393e0e4c8e300e0caec

BookLover

hero member

Activity: 533

Merit: 500

^Bitcoin Library of Congress.

What could cause this to happen and how could it be prevented?

2112

legendary

Activity: 2128

Merit: 1073

Quote from: bfever on September 26, 2011, 02:35:37 PM

So that's only 0.001 bitcoin not yet accounted for...

I think those are the transaction fees that are available in that block but unclaimed by the miner.

bfever

jr. member

Activity: 39

Merit: 1

According to my database (it only stores bitcoins in txouts not spent, that takes only 1.86 seconds to get the result), I get 727699999899998 satoshi's available after 145542 blocks, which means there are 100.00100002 "lost".
2x 50 coins are "lost" due to duplicate transactions in generation, which my database didn't like at first (because it has a unique tx hash index).
Didn't know up to know if the others where rounding errors on my side, but it seems the 2 satoshi's are indeed from block 124724.
So that's only 0.001 bitcoin not yet accounted for... Huh

theymos

administrator

Activity: 5222

Merit: 13032

Yeah, I was definitely off by 100 BTC. The number lost is actually 100.01000001. All losses are accounted for, then: 100 BTC from duplicates and 0.01000001 from the transaction dree12 linked to (0.01 fee that BBE mishandles plus the satoshi dropped purposefully by the miner).

Quote from: dree12 on September 24, 2011, 03:36:07 PM

You wasted 10 minutes to help me - I'm honored! I sent a tiny donation as a token of thanks.

Thanks!

maaku

legendary

Activity: 905

Merit: 1012

Interesting, thanks.

theymos

administrator

Activity: 5222

Merit: 13032

Quote from: maaku

@theymos: that's an awfully round number. Are there 4 blocks that didn't generate bitcoins at all?

At least two blocks didn't generate any BTC:
http://blockexplorer.com/block/00000000000a4d0a398161ffc163c503763b1f4360639393e0e4c8e300e0caec
http://blockexplorer.com/block/00000000000743f190a18c5577a3c2d2a1f610ae9601ac046a38084ccb7cd721

I'm not sure where where the other BTC was lost. My current database structure doesn't allow me to easily get the particulars. It's also possible my calculation was incorrect.

ShadowOfHarbringer

legendary

Activity: 1470

Merit: 1006

Bringing Legendary Har® to you since 1952

Quote from: maaku on September 24, 2011, 06:24:41 PM

Looks like a buggy miner subtracted the Tx fee instead of adding it--but why was the block accepted by the network?

Exactly. That could be a serious weakness in the protocol.
Why would all other clients accept such blocks ?

Shoudn't there be a rule that only allows relaying/accepting of completely valid and "full" blocks ?

For example: if a huge mining pool suddenly breaks down and starts producing blocks which earn 0 BTC to the network, then a lot of BTC could be lost in the process.

maaku

legendary

Activity: 905

Merit: 1012

@ShadowOfHarbringer: those 0.00000002 BTC were never generated. Transactions are allowed to have fewer TxOut than TxIn--the difference is the Tx fee. Does the Satoshi client allow for the same discrepancy in the generating transaction? That would be news to me but explain what's going on here. The miner is failing to claim as many BTC as they are entitled to, resulting in fewer BTC generated for that block than would be expected. So this isn't really a case of coins being destroyed as much as new coins not being minted--but if the miner set the generator Tx0ut to zero, those transaction fees would be destroyed.

Anyone know why this happened? Looks like a buggy miner subtracted the Tx fee instead of adding it--but why was the block accepted by the network?

@theymos: that's an awfully round number. Are there 4 blocks that didn't generate bitcoins at all?

iamzill

sr. member

Activity: 677

Merit: 250

Quote from: error on September 24, 2011, 04:47:27 PM

Quote from: iamzill on September 24, 2011, 03:53:56 PM

Sorry for the stupid question, but how did 20 nanobitcoins get destroyed in that block? I thought bitcoins never gets destroyed, they can only become irretrievable?

Did you not see that the generated coins were 49.99999999 instead of 50?

No, I missed it.

So how did this happen? Did a miner intentionally reduce his profits? Was it a bug in his code? How come all other nodes accepted this block?

ShadowOfHarbringer

legendary

Activity: 1470

Merit: 1006

Bringing Legendary Har® to you since 1952

Quote from: error on September 24, 2011, 04:47:27 PM

Quote from: iamzill on September 24, 2011, 03:53:56 PM

Sorry for the stupid question, but how did 20 nanobitcoins get destroyed in that block? I thought bitcoins never gets destroyed, they can only become irretrievable?

Did you not see that the generated coins were 49.99999999 instead of 50?

More important questions:

1. Was that expected when the Bitcoin protocol was designed, or is this something new ?
2. Is it proper for a block to generate 49.99999999 bitcoins instead of the usual 50 ? Where did the 0.00000001 bitcoins go ?
3. If it is not proper, why wouldn't the network reject such a block ?

error

hero member

Activity: 588

Merit: 500

Quote from: iamzill on September 24, 2011, 03:53:56 PM

Sorry for the stupid question, but how did 20 nanobitcoins get destroyed in that block? I thought bitcoins never gets destroyed, they can only become irretrievable?

Did you not see that the generated coins were 49.99999999 instead of 50?

iamzill

sr. member

Activity: 677

Merit: 250

Sorry for the stupid question, but how did 20 nanobitcoins get destroyed in that block? I thought bitcoins never gets destroyed, they can only become irretrievable?

dree12

legendary

Activity: 1246

Merit: 1077

Quote from: theymos on September 24, 2011, 03:26:21 PM

Quote from: dree12 on September 24, 2011, 03:21:21 PM

Okay, thanks. How did you obtain that number: ran a script over the blockchain? ABE?

I queried the BBE database. It currently takes like 10 minutes to compute, though, which is why I don't make it available on any page.

You wasted 10 minutes to help me - I'm honored! I sent a tiny donation as a token of thanks.

theymos

administrator

Activity: 5222

Merit: 13032

Quote from: dree12 on September 24, 2011, 03:21:21 PM

Okay, thanks. How did you obtain that number: ran a script over the blockchain? ABE?

I queried the BBE database. It currently takes like 10 minutes to compute, though, which is why I don't make it available on any page.

dree12

legendary

Activity: 1246

Merit: 1077

Quote from: theymos on September 24, 2011, 03:17:38 PM

It's the upper limit. If you remove coins that have been obviously destroyed in that way, the number would be 200.01000001 less than the upper limit (at the moment).

Okay, thanks. How did you obtain that number: ran a script over the blockchain? ABE?

theymos

administrator

Activity: 5222

Merit: 13032

It's the upper limit. If you remove coins that have been obviously destroyed in that way, the number would be 200.01000001 less than the upper limit (at the moment).

Topic: Is blockexplorer's total bitcoins in existance accurate? - page 2. (Read 3250 times)