<p>I've been looking at the live mempool on mempool.space, and while most transactions are sorted in order of highest sat/vB to lowest, I've noticed some that standout with extremely high sat/vB but are placed further back in the block.</p>
<p>I've tried looking for reasons why, such as a parent-child dependency, but I couldn't figure it out.</p>
<p>What exactly determines this ordering? I'm wondering what the incentive of agreeing to a much higher rate is, if your transaction will be fulfilled later than others in the block, or potentially even pushed back to the next one.</p>

CC BY-SA 4.0
2024-02-26T10:50:03.820Z
You tagged the question bitcoin-core, can you confirm you want to know specifically how bitcoin core's [`getblocktemplate`](https://developer.bitcoin.org/reference/rpc/getblocktemplate.html) selects and orders transactions rather than how other mining software and other algorithms work?
RedGrittyBrick
CC BY-SA 4.0
2024-02-26T10:54:29.653Z
Does this answer your question? [Why does getblocktemplate use priority for transaction selection?](https://bitcoin.stackexchange.com/questions/46185/why-does-getblocktemplate-use-priority-for-transaction-selection)
RedGrittyBrick
CC BY-SA 4.0
2024-02-26T13:05:50.697Z
@RedGrittyBrick: I don’t think that’s related. Coin-age priority was disabled by default in Bitcoin Core v0.12
Murch
CC BY-SA 4.0
2024-02-26T20:09:13.807Z
Pieter's answer does mention that the priority based selection was replaced by a CPFP algorithm.
RedGrittyBrick
CC BY-SA 4.0
2024-03-01T08:59:14.363Z
@RedGrittyBrick that post helped me deepen my understanding a lot, thanks. I think my question has been answered. Additionally, I realized that I was looking at the fee rate, when the effective fee rate is what's being used to order the transactions in most cases.
Blank Dev
<bitcoin-core><transaction-fees><mining-theory><transaction-selection><getblocktemplate>
What determines the order of transactions in a block?
Blank Dev
# What determines the order of transactions in a block?

(Asked by: username_0 on 2024-02-26)

I've been looking at the live mempool on mempool.space, and while most transactions are sorted in order of highest sat/vB to lowest, I've noticed some that standout with extremely high sat/vB but are placed further back in the block.

I've tried looking for reasons why, such as a parent-child dependency, but I couldn't figure it out.

What exactly determines this ordering? I'm wondering what the incentive of agreeing to a much higher rate is, if your transaction will be fulfilled later than others in the block, or potentially even pushed back to the next one.

**Tags:** bitcoin-core, transaction-fees, mining-theory, transaction-selection, getblocktemplate

> **Comments:**
> **username_1**: You tagged the question bitcoin-core, can you confirm you want to know specifically how bitcoin core's [`getblocktemplate`](https://developer.bitcoin.org/reference/rpc/getblocktemplate.html) selects and orders transactions rather than how other mining software and other algorithms work?  
> **username_1**: Does this answer your question? [Why does getblocktemplate use priority for transaction selection?](https://bitcoin.stackexchange.com/questions/46185/why-does-getblocktemplate-use-priority-for-transaction-selection)  
> **username_2**: @username_1: I don’t think that’s related. Coin-age priority was disabled by default in Bitcoin Core v0.12  
> **username_1**: Pieter's answer does mention that the priority based selection was replaced by a CPFP algorithm.  
> **username_0**: @username_1 that post helped me deepen my understanding a lot, thanks. I think my question has been answered. Additionally, I realized that I was looking at the fee rate, when the effective fee rate is what's being used to order the transactions in most cases.  

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## 0 answers

