Question about transaction

[Oshosondy]

Three days ago, I made a transaction from my coinomi wallet into electrum, the reason for the transaction was to test if truly electrum is now supporting rbf in a way not to only pump the fee but to also be able to cancel the transaction because I have no fund on it at that time because I use it often and I lack fund at the time. The transaction was unconfirmed for three days, but I send bitcoin to one of my friends on the same coinomi wallet, but I did not use 0.00002 btc that I use for previous transaction fee, I increased the fee to 0.00015 btc so the transaction will be confirmed fast due to mempool congestion, I later checked for the txid on coinomi in about three hours later, I saw the bitcoin I first sent to my electrum wallet confirmed, and the bitcoin I sent to my friend confirmed, the two transactions were confirmed at ones at the same time.

My questions are:
1. Two days ago before the transactions was confirmed, I checked my electrum wallet many times, it did not sync and was perfectly offline, this has not happened to me before and I have good data connection, I wanted to even ask for solution on this forum before but I postponed it. Immediately I saw the bitcoin confirmed on coinomi, I later check the electrum wallet, it was able to sync again. Is that normal? That if a transaction is not confirmed, you will not be able to use your electrum wallet in such a way it will be offline at the time until the transactions is confirmed? My network is working perfect and I am not that novice about this and I was surprised. I was able to sync my electrum wallet some hours after the transaction, but when it was not confirmed for a day, the inability to sync stared.

2. When I sent to my friend with higher fee, the previous transaction to electrum wallet was confirmed at the same minute when my friend transaction was confirmed, I think that is called cpfp? I have read about it before but I do not know how it works. Just to be 100% certain.

3. Is it true that electrum wallet rbf can now be used to cancel a transaction? I should have experimented it myself but transaction fee is too high for now.

[Rath_]

Immediately I saw the bitcoin confirmed on coinomi, I later check the electrum wallet, it was able to sync again. Is that normal?

Yes, some Electrum servers might be overloaded right now. They are hosted by the community. If it ever happens again, you can try changing the server manually.

2. When I sent to my friend with higher fee, the previous transaction to electrum wallet was confirmed at the same minute when my friend transaction was confirmed, I think that is called cpfp?

If you sent the transaction to your friend from your Electrum wallet and used unconfirmed coins in the process, that would be CPFP. Otherwise, it was a pure coincidence.

3. Is it true that electrum wallet rbf can now be used to cancel a transaction? I should have experimented it myself but transaction fee is too high for now.

You could have always done that manually if you had RBF enabled. If you are running the latest version of Electrum then you can use "Cancel tx" feature to double-spend your unconfirmed transaction using RBF to yourself.

[NeuroticFish]

Is that normal? That if a transaction is not confirmed, you will not be able to use your electrum wallet in such a way it will be offline at the time until the transactions is confirmed?

It was a bad coincidence. You can normally connect and use Electrum after sending a transaction.
Keep in mind that Electrum uses 3rd party servers your client is connecting to. You may have tried to connect by default to a server with connectivity issues.
Probably after more use of Electrum it'll cache a better list of servers. So as long as you have the latest Electrum and you have verified it, you should have nothing to worry about.

2. When I sent to my friend with higher fee, the previous transaction to electrum wallet was confirmed at the same minute when my friend transaction was confirmed, I think that is called cpfp? I have read about it before but I do not know how it works. Just to be 100% certain.

If you used as input a transaction with 0 confirmations, you used a high fee and it made the parent and your transaction confirm fast(er) (and usually in the same block) then yes, you did CPFP.
(From your explanation it's not 100% clear to me what you've done.)

3. Is it true that electrum wallet rbf can now be used to cancel a transaction? I should have experimented it myself but transaction fee is too high for now.

Yes and no. It won't cancel a transaction, it will "redirect" (replace) a transaction. This way you can send it to the same recipient, or another recipient or yourself.
And this works only if the transaction is not yet confirmed. Cancel Tx will just make the transaction go to yourself.

If you want to experiment, there's always testnet. There are testnet faucets where you can get testent coins for experimenting.
All you have to do is to start Electrum with the parameter --testnet


Edit: I see that except the testent part the previous post has covered the questions. However, I've explained different. Still, if anybody considers it redundant please let me know and I'll remove mine.

[bob123]

Is that normal? That if a transaction is not confirmed, you will not be able to use your electrum wallet in such a way it will be offline at the time until the transactions is confirmed?

No, it's not.
Your wallet stays fully functional while a transaction is being confirmed. It was just a coincidence.

2. When I sent to my friend with higher fee, the previous transaction to electrum wallet was confirmed at the same minute when my friend transaction was confirmed, I think that is called cpfp? I have read about it before but I do not know how it works. Just to be 100% certain.

A CPFP means to use unconfirmed outputs from a parent transaction as new inputs in a new (child) transaction with a fee high enough to pay for both transactions.
If the total fee rate of both transactions is worth it, miners do want to include your second transaction which requires them to also confirm the first transaction. This can happen in the same block.

If you did use unconfirmed outputs as an input (e.g. by using some change), then it indeed was a CPFP. Otherwise not.

3. Is it true that electrum wallet rbf can now be used to cancel a transaction? I should have experimented it myself but transaction fee is too high for now.

Transactions never can be cancelled.
But electrum offers to replace an unconfirmed transaction by broadcasting one sending the funds to yourself.

Please note that a transaction is not completed until it has at least 1 confirmation. At that point it can't be cancelled anymore.

[Oshosondy]

It could be coincidence since AFAIK Electrum won't prioritize unconfirmed input. You should check whether second transaction use output of first transaction as the input.

Thanks for the reply, I have found it out to be cpfp. Although, I was a coincidence like you have said.

RBF meant to allow user to replace unconfirmed transaction, but it could be used to cancel unconfirmed transaction. Electrum simply enable user to do it easily.

I was able to do this recently, thanks for the reply. But, I was charged more fee to cancel the transaction, which means it was just represented with canceled transaction but I think the transaction was only just introduced back into the address that sent it, not in a way that is actually canceled which is the reason for more fee to be paid for, this is just what I thought.

[o_e_l_e_o]

I was able to do this recently, thanks for the reply. But, I was charged more fee to cancel the transaction, which means it was just represented with canceled transaction but I think the transaction was only just introduced back into the address that sent it, not in a way that is actually canceled which is the reason for more fee to be paid for, this is just what I thought.

That is correct. "Cancel" is a bit of misnomer - there is no way to broadcast to the network that you wish a just transaction to be cancelled. The only way to effectively cancel a transaction is to render it invalid by spending at least one of the inputs which it spends. That is what this button does - it creates a new transaction which uses the same input(s) to the transaction you are "cancelling", and simply sends them back to yourself. It does this with a higher fee than the transaction you are replacing, so this second transaction is mined first and the first transaction becomes invalid.