Many users of the system face the need to cancel a transaction on the blockchain, since more and more often transactions freeze and funds are debited from the wallet. But can such a cancellation be done? And if so, how?
Blockchain technology is designed in such a way that any operations and transactions, if they have already been carried out, cannot be canceled. However, if the transaction has not received confirmation, it will "hang" in the system for several days to no avail. And in such a case, bitcoins will be debited from the wallet. And given their course, the problem turns out to be serious.
However, there is a way out. And it is based on the fact that transactions do not freeze just like that - in each case there is a reason: something that did not suit the blockchain system. If we can figure it out, then we will be able to solve the problem of a transaction stuck in the system.
The most common cause of stuck transactions is the following:
- overload of the blockchain system itself;
- the formation of so-called mempools - queues for the execution of transactions.
The fact is that the popularity of bitcoin as a rather expensive cryptocurrency is growing more and more, which attracts many new users to the system. Many of them decide on different operations without really understanding their structure, and as a result they get confused. And the blockchain system perceives the actions of such users unequivocally - as inadequate, and reacts sharply: overload and freeze. Naturally, the transaction in this case does not go through and also hangs.
As for mempools, they arise for several reasons:
- a very large number of users want to make a deal, but the blocks they fill in simply cannot physically be included in the system at the same time - a mempool appears;
- transfers with a high commission are the first and are less likely to run the risk of a queue, and if the user has set a low commission or did not indicate it at all, the mempool (and for a long time) is provided to him.
Moreover, in the latter case, one cannot even guarantee that this transaction will go through at all, since it will be sent to the commission market, and miners may not pay attention to it - the transaction will simply hang in their mempool until they find a new block.
So what can be done to solve the problem in both the first and second cases? Try to either "push" the transaction further, or cancel it, if still possible. There are several options for action:
- You can try to use doublespend - the double spend option, which will ensure the transaction movement, i.e. the option of "pushing through" by increasing the commission, if initially it was too low. This is possible because counterparties only check assets in their accounts at one particular moment. This means that if the transaction is frozen, you can send another one with an increase in commission. Both transactions will fail, no need to worry about that.
- Using CPFP is a mechanism that allows you to create a transaction with one input (it must necessarily be the output of a problem transaction - the same change, for example) and send bitcoins to yourself.
- Using special accelerators for transactions that can be used by both the recipient and the sender.
But none of these methods provide an absolute guarantee that the transaction will still be canceled or pushed through. And no method in this case will give such guarantees, because, as already mentioned, the blockchain system is designed in such a way that it does not provide for the cancellation of transactions. If they have already been confirmed (included in the block), no method will help, but if they are stuck before confirmation, you can try.
And we must remember that an unconfirmed transaction cannot be canceled by itself. In this case, it is only possible to change the display in the user's wallet.
