<p>There are no rules, miners can pick the transactions they want to include in the block.</p>

<p>Unconfirmed transactions sit in the miners "mempool". And when size of the "mempool" becomes too high, miners may decide to clear out some old transactions. </p>

<p>But there are no hard and fast rules, so you should think twice before sending transactions to the node.</p>

CC BY-SA 3.0
2018-02-26T18:58:39.163Z
2018-02-26T18:58:39.163Z
Preet
<p>I'm playing around with <code>myst</code> wallet on a private network, and noticed this option while sending funds between wallets:
<a href="https://i.sstatic.net/88Swp.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/88Swp.png" alt="enter image description here"></a></p>

<p>This is ETH, but I'm also interested how other networks handle this issue.</p>

<p>So I started to wonder - is it possible that in abundance of high fee transactions to add (mine), my transaction would never be applied to a block? In a similar fashion like low priority processes can get starved?</p>

<p>Or maybe there is some mechanisms that will ensure that my transaction gets through?</p>

<p>I can imagine such mechanism like this: each miner has to pick at most 90% transaction with high fee, and 10% transactions with low fee. This way - low fee queue can get clogged, but if it's a FIFO queue - those would be processed eventually. 
As opposed to the approach where <code>take X transactions ordered by fee desc</code> would allow to high fee transactions to flow in virtually starving everything else.</p>

<mining-theory>
Is it possible for the transaction to be on hold forever?
Greg
# Is it possible for the transaction to be on hold forever?

(Asked by: username_0 on 2018-02-26)

I'm playing around with `myst` wallet on a private network, and noticed this option while sending funds between wallets:
[![enter image description here](https://i.sstatic.net/88Swp.png)](https://i.sstatic.net/88Swp.png)

This is ETH, but I'm also interested how other networks handle this issue.

So I started to wonder - is it possible that in abundance of high fee transactions to add (mine), my transaction would never be applied to a block? In a similar fashion like low priority processes can get starved?

Or maybe there is some mechanisms that will ensure that my transaction gets through?

I can imagine such mechanism like this: each miner has to pick at most 90% transaction with high fee, and 10% transactions with low fee. This way - low fee queue can get clogged, but if it's a FIFO queue - those would be processed eventually.
As opposed to the approach where `take X transactions ordered by fee desc` would allow to high fee transactions to flow in virtually starving everything else.

**Tags:** mining-theory


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## 1 answers

### Answer by username_1 on 2018-02-26. Score: 4 | Accepted answer

There are no rules, miners can pick the transactions they want to include in the block.

Unconfirmed transactions sit in the miners "mempool". And when size of the "mempool" becomes too high, miners may decide to clear out some old transactions.

But there are no hard and fast rules, so you should think twice before sending transactions to the node.


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