Questions tagged [transaction-selection]

Questions about what criteria influence the selection of unconfirmed transactions for block inclusion.

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26
votes
4answers
16k views

How do miners select which transactions to include in a block?

Where and how do you view and select which transactions to include in the block you are trying to create? Do you look on the blockchain? Is there some tool that you can use that allows you to see ...
14
votes
1answer
1k views

Are there any pools or large miners running "child pays for parent" patch?

A feature available through pull #1647 gives the recipient of a transaction a method to help get a transaction to confirm. This feature is called "child pays for parent", and what it means is that ...
13
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4answers
21k views

relationship between bitcoin miner and verification of transactions [closed]

Bitcoin miner mines a block, which can't be submitted to the network without proof of work. And the new block contains all of the new transactions. Hence the new block acts as a security measure, and ...
11
votes
2answers
1k views

Double spend attack by sending higher fee transaction directly to the pools possible?

The standard client prioritizes TXs by the time of receipt, e.g. a conflicting transaction will not be relayed. This is not enforced by the network, though. Is there anything that would prevent this ...
11
votes
2answers
610 views

In a double spend attempt, how is the valid transaction chosen?

Suppose I publish the private key of an address that contains 1 bitcoin. If two people try to transfer this bitcoin to another address before a new block is found, who gets it? How is this decision ...
11
votes
2answers
512 views

Are any miners still considering priority in their transaction selection?

A new answer on Who gets Bitcoin transaction fees? has spawned discussion on the paradigm shift from selection by priority (= coin age × spent value) to selection by fee rate (= fee / transaction size)...
11
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2answers
3k views

Why does Antpool mine so many empty blocks?

AntPool, the largest mining pool mines a lot of empty blocks (quick stat over the last 100 blocks they mined at time of writing shows 20% <10kB). While I understand that sometimes it is useful to ...
9
votes
1answer
1k views

What is the motivation for miners to include all recent transactions in a block?

I think I understand the basic operation of the Bitcoin protocol. Blocks are the "long-term memory" of the network used to prevent double spending (and the way the network agrees in first place). ...
9
votes
1answer
29k views

Whats the process of Creating a Block on the BlockChain

have been mining on pools and blindly going a long for the ride of > generating a block Can somebody walk through the process in simple terms of the steps involved in creating a block on the ...
9
votes
1answer
2k views

Bitcoin transaction priority calculation

From the Bitcoin wiki page on transaction fees: Transaction priority is calculated as a value-weighted sum of input age, divided by transaction size in bytes: priority = sum(...
8
votes
1answer
578 views

What is the largest number of blocks a transaction has ever waited for confirmation?

What is the largest number of blocks a transaction has ever waited before eventual confirmation? Please exclude: Transactions with no fee Transactions delayed because of unconfirmed inputs ...
7
votes
1answer
295 views

What if some group of people start sending small transactions from wallet to wallet just to make the blockchain bigger?

What if some government start using their computers to move the tiniest amount of Bitcoin possible, from wallet to wallet, just to make the blockchain REALLY big? Is this possible? And also, is it ...
7
votes
1answer
2k views

If I offer a higher transaction fee, will my order get processed faster?

I was reading the wiki and it seemed to sugest that the transaction fees didn't play to much of a role in determining the priority of an order but rather the actual size in bytes and the previous ...
6
votes
1answer
4k views

How do miners choose transactions?

I am a little puzzled about how miners choose transactions, are the people who want to transfer Bitcoin sending their transaction to miners asking them to validate them, or are they put somewhere and ...
6
votes
2answers
856 views

Does a new block necessarily include all transactions that occurred before its generation? What about network latency?

I read What exactly is Mining? and What are bitcoin miners really solving?, but was left wondering: What happens if a new transaction comes in, whilst mining? To answer that, I found Do transactions ...
6
votes
2answers
1k views

Creating empty blocks vs creating full blocks

I've already read many different answers to this topic. Is it correct that the miner decides on his own if he includes any transactions in his block and how many (as long as the block size is <...
6
votes
1answer
263 views

Do any pools discriminate against some transactions?

Are there any pools that openly discriminate against some transactions? For example, they only put transactions with a fee in their blocks, thus ignoring all "free" transactions?
5
votes
2answers
619 views

Is the transaction pool global or local?

I can't find anything in the web about that topic. Do all the miners have one global pool filled with transactions, i. e. Miner 1 takes Transaction 1 into his candidate block, so Transaction 1 won't ...
5
votes
1answer
647 views

How does getblocktemplate select transactions?

I wrote a script that compares the transactions listed in the memory pool with the transactions included in getblocktemplate: http://learnmeabitcoin.com/explorer/node/memorypool (I've ordered the ...
5
votes
2answers
2k views

As of 2017 is it still possible to get a transaction confirmed without a fee?

In the past it was possible to get a transaction without a fee confirmed if the inputs and outputs had a high enough priority and followed some rules. As of 2017 is a "free" transaction still possible ...
5
votes
1answer
3k views

How can a miner choose which transaction to include in the next block?

This question is not a duplicate of Can miners choose which transactions to mine? Everybody seems to agree on the fact that miners can select which transactions they are mining. But I can't find a way ...
5
votes
2answers
464 views

Is it possible to increase the transaction fee of a sent transaction not yet in a block?

Is it possible to increase transaction fee of a transaction that is already sent and seems stuck?
5
votes
1answer
429 views

How does Bitcoin Core sort memory pool transactions by fee?

I'm trying to understand the algorithm Bitcoin Core uses to sort memory pool transactions by fee. Gavin's fee rework proposal states: Next, sort all remaining memory pool transactions by fee-paid-...
5
votes
1answer
2k views

What are the internal details of GetWork() .. the foundation of Bitcoin mining?

According to this answer GetWork() sends "a chunk of data containing the block data, including the randomized bits, and the nonce (the bit which the miner changes)." Can anyone provide details on ...
4
votes
2answers
1k views

Does the amount of the transaction fee affect the priority of a transaction?

I've been reading about transaction fees here. From the aritcle, Transaction priority is calculated as a value-weighted sum of input age, divided by transaction size in bytes: priority = sum(...
4
votes
2answers
72 views

Are sequential blocks more likely to be "empty" if solved by the same entity?

If not SPV mining, so-called "empty blocks" occur if there are no available transactions to include and is usually when the previous block was solved a short period of time previously. Is there any ...
4
votes
2answers
385 views

Will a new block be found immediately, when there are enough transactions to fill a block?

I am trying understand the Bitcoin verification process. What happens, if a new block has not been found and there are enough transactions waiting to fill the current block size limit? Will a new ...
4
votes
1answer
1k views

How often do miners update their block transaction list?

Assuming an interval where no block is found, do we know how often the typical miner updates his block transaction list with new transactions from the mempool? I found a reference which suggests that ...
4
votes
1answer
355 views

Would it be possible to create a mining pool service that specifically processed only certain transactions?

I've seen that it's possible to encode custom data in the block chain. I'm wondering if it's possible for someone to start a mining pool consisting of client that use some metadata in either wallets ...
3
votes
2answers
713 views

Is there a minimum number of transactions in a block?

What encourages Bitcoin miners to include lots of transactions in blocks in the Bitcoin blockchain? It seems like you could quickly add a block with just a single transaction and get the block reward ...
3
votes
2answers
255 views

Why is the block size is not filled with transactions?

Since a miner can acquire the fees from the transactions in a block, the miner should package as many transactions as possible in a block. However, I recently found a block (blocknum: 602297) with a ...
3
votes
1answer
154 views

Miner transaction selection - how are sigops considered?

There is a limit on how much a block can sigop (set to 80000?). There is also a limit on how much a single transaction can sigop (set to 16000?). It thus seems possible (and if it's not possible, the ...
3
votes
1answer
500 views

How to 'pick' transactions to include when attempting to add a new block?

I saw this question about finding new transactions. But how do you pick which transactions to include in the block you're trying to add? Should it be in a certain order, or random? How many ...
3
votes
2answers
49 views

Which transaction would get confirmed in an uncongested network?

Scenario: Mallory sends some bitcoin with a $1 fee Later, Mallory double spends her transaction with a $5 fee A new block is found In an uncongested network with an average transaction fee of ~20 ...
3
votes
2answers
731 views

What factors determine how long confirmation takes?

Simple question... What are all the factors (all of them!) that determine how much time X number of confirmations of a transaction takes?
3
votes
1answer
203 views

How does a miner choose which transactions go into the next block?

How does a miner choose which transactions go into the next block? Do all transactions go through or is there a lottery process? I understand transactions with higher fees are given priority.
3
votes
1answer
245 views

Is it OK not to sort transactions at all?

According to Mastering Bitcoin. Mining - Transaction Age, Fees, and Priority, miners sort transactions, using special parameter, called priority, which looks like Priority = Sum (Value of input * ...
3
votes
1answer
375 views

Transaction inclusion into block

What are reliable and good sources for understanding the procedure of transaction inclusion into a block? Problem outline: Given, there are multiple peers - let's say 5 - in a test network, where 3 ...
3
votes
2answers
609 views

How are unconfirmed transactions divided into different blocks?

According to https://bitcointalk.org/index.php?topic=216938.0 one transaction can only be contained in one block. If I understand correctly, miners can freely decide what transaction they include in ...
3
votes
1answer
180 views

Mine valid but nonstandard transactions

Is there a way to configure cgminer to accept valid but nonstandard transactions for mining? If not, where, theoretically, would be a good place to look if I was interested in mining nonstandard ...
3
votes
1answer
544 views

What are the requirements of a transaction being included in a block?

What are the requirements of a transaction being included in a block? How does a miner verify that a transaction meets such requirements?
2
votes
2answers
614 views

When we can agree on mempool sorting order, we can just confirm first n-transactions that are at least 10 mins old. What's missing?

When we can agree on a mempool sorting order, we can just confirm first n-transactions (or 80% of transactions) that are at least 10 minutes old. Then, we can transfer (broadcast) the block header ...
2
votes
1answer
464 views

What is criteria of mining priority except for transaction-fee?

I am reading "Mastering Bitcoin written by Andreas" and I found this explanation of mining. Transactions are added to the new block, prioritized by the highest-fee transactions first and a few ...
2
votes
2answers
236 views

What were 'high-priority' transactions in Bitcoin Core v0.9?

I came across these release notes for Bitcoin Core 0.9 and saw this quote under 'Transaction Fees'. Does this distinction between 'high-priority' and 'highest-fee' transactions still exist? What ...
2
votes
2answers
536 views

How often do miners recalculate the merkle root they're working on?

I think that I understood most of the things about Bitcoin but there is still a mystery. We can see on https://blockchain.info/ that there are up to 4/5 new transactions every seconds. My question ...
2
votes
3answers
602 views

Transactions are not guaranted to be validated

I have read some posts about transactions never to be confirmed, but those post implied small transfers with no fees. In my case my two transactions have something like 0.000428 BTC of fee. I don't ...
2
votes
1answer
503 views

How is the mempool incorporated in the calculation of the block hash?

So I've been reading about how the nonce is calculated. There is one part that I don't get. So there is a mempool, and each node (or mining node) takes a part (or the whole part) of that mempool, ...
2
votes
2answers
265 views

How are transactions collected into new block?

How are the latest transactions collected into new block to send them to miners for hashing? Which part of the network is responsible for giving miners the correct block to hash?
2
votes
1answer
154 views

Transaction with a high fee keeps getting skipped... Reason why?

I was sent a transaction that has been unconfirmed for 3 days now - but the feerate is relatively high (53.8 sat/vB). Blocks have been confirming transactions with lower feerates for days, but for ...
2
votes
1answer
39 views

Could a miner set a maximium transaction fee rate?

Could a miner set a maximimum transaction fee rate? I mean validate only transactions between x and y satoshis/byte? I know is not clever. Is it possible?