All you need to know about Unconfirmed transactions and what to do about them.

[boybugs18]

After about 48 72 hours transactions may be forgotten which means nodes will stop broadcasting it and it is possible that your transaction disappears.

so do we have to find/hire a miner to mine that transaction for us so we can retrieve the bitcoin that the nodes have been forgotten or it will dissappear? I just have this thoughts so in the future I know the answer and not be ignorant about it thanks in behalf of who will answer first.

[Coding Enthusiast]

After about 48 72 hours transactions may be forgotten which means nodes will stop broadcasting it and it is possible that your transaction disappears.

so do we have to find/hire a miner to mine that transaction for us so we can retrieve the bitcoin that the nodes have been forgotten or it will dissappear? I just have this thoughts so in the future I know the answer and not be ignorant about it thanks in behalf of who will answer first.

When you broadcast a transaction it propagates through the network in matter of seconds and it stays in the mempool (all the nodes are broadcasting it), now this transaction can not stay there forever otherwise size of the mempool would go up extremely fast to an unmanageable size.
To fix this, nodes will drop transactions that have not been confirmed for a certain amount of time (default in bitcoin core is 72 hours). Not all nodes have this default setting though.

If you are the sender, you can send the same transaction from your wallet (if you are a full node by just opening your wallet and connecting) or you can spend it again.
If you are the receiver, the only thing you can do is to save the transaction hex and push it yourself if it was dropped. do this by adding a ?format=hex tag at the end of blockchain.info/tx/..... links.

[Kprawn]

If you pay a fee to miners on top of the fees that you included in your original tx, then things will quickly escalate into a situation where

"spam" attacks will become more popular. They would run this, just to "double dip" on the fees.  ... We should find a way, to

eliminate and avoid this scenario, rather than promoting methods to "repair" it. That said, your thread is still extremely helpful in the

situation we have now... so thumbs up for that. 

[ice18]

A very well-explained thread regarding unconfirmed transactions,thanks to op nice info well use it for future reference.

[digaran]

So it is safe to assume micro transaction part of the bitcoin concept is dead already? when miners confirm transactions only the block winner receives the fees in addition to the 12.5 bitcoins, with the current drama the most powerful pools are becoming the central authority figures of bitcoin and soon they'll start to dictate their terms and conditions.

[C0RE]

If I put zero fee, is it possible that my transactions will be confirmed anyway?

[mace15]

I have experience this in my wallet that took a lot of hours to confirm. It tooks 24hours to confirm in my wallet. When I check in blockchain.info unconfirmed transactions. Anyway, thanks for these information why and whats reason its unconfirmed transactions.

[iram3130]

If you pay a fee to miners on top of the fees that you included in your original tx, then things will quickly escalate into a situation where

"spam" attacks will become more popular. They would run this, just to "double dip" on the fees. ... We should find a way, to

eliminate and avoid this scenario, rather than promoting methods to "repair" it. That said, your thread is still extremely helpful in the

situation we have now... so thumbs up for that.

Spam attacks and double tip situations will just make things worse than what it is right now. And paying more fees to miners will be a short term solution which is not good for the future of Bitcoin.
Thank you, OP for such an informative post.

[sportis]

--snip--

You can however calculate an estimated size if you insist on using BC.I. A rough estimate is this:

Code:

inputCount*180 + outputCount*34 + 10 ± inputCount*1

ref

it's "replaceable" the same as abandon transaction in bitcoin core, because there is not such option in core, but maybe they do the same thing?

The funny thing is RBF existed from very early version and it was added in 0.12.0 and I can not find it in bitcoin core (0.13.0 I should upgrade soon :/) apart from mempool which is about relaying the RBF transactions not making them.

From my point of view, not only for completeness of this post but for practical reasons too, given that now often we see 150s/b, you could point that above estimation of fees is based when public keys are uncompressed. But when public keys are compressed (nowadays usually are) then someone have to replace the value 180 with shorter one that is 148.

[pooya87]

If I put zero fee, is it possible that my transactions will be confirmed anyway?

that is also a possibility but it is a race, when there are 70,000 transactions which at least (with a big optimistic view) 50,000 one of them have high fees such as 0.0003BTC fees per byte, nobody will mine your zero fee transaction.

[kiklo]

If I put zero fee, is it possible that my transactions will be confirmed anyway?

that is also a possibility but it is a race, when there are 70,000 transactions which at least (with a big optimistic view) 50,000 one of them have high fees such as 0.0003BTC fees per byte, nobody will mine your zero fee transaction.

Odds are a Zero Fee transaction will be ignored.
(and it will do nothing but lock up the transaction for ~72 hours before it is released back to you.)

https://www.cryptocoinsnews.com/death-zero-fee-bitcoin-transaction/

Zero-fee transactions were the norm in 2011, the exception in 2012, increasingly rare since, and now finally gone.

For a long time in Bitcoin’s existence, miners would process transactions without fees.
All miners today expect transactions to include fees due to the overall volume of the network and to avoid spamming of the Bitcoin network.

 

[Quickseller]

I believe that you can use CPFP if you are the sender to the extent that your transaction sends change to an address whose private key(s) you control.

[Coding Enthusiast]

I believe that you can use CPFP if you are the sender to the extent that your transaction sends change to an address whose private key(s) you control.

Technically speaking it should be possible, as long as you own the private key to one of the outputs in order to spend it.
But I didn't put it under "Sender" section because as a sender there are better options such as opt-in RBF.

I think it is worth mentioning here that Electrum will have CPFP feature in its new release (2. along with SegWit support.

[pooya87]

If you pay a fee to miners on top of the fees that you included in your original tx, then things will quickly escalate into a situation where

"spam" attacks will become more popular. They would run this, just to "double dip" on the fees.  ... We should find a way, to

eliminate and avoid this scenario, rather than promoting methods to "repair" it. That said, your thread is still extremely helpful in the

situation we have now... so thumbs up for that. 

You mention that there are spammers causing all the delays. Who are they and what are they trying to do besides clogging up the network? Is it hackers from competing cryptocurrencies?

this is off-topic here but take a look at this topic https://bitcointalk.org/index.php?topic=1776143.0 which can be a possible case of the spammers and you may get the gist of what is going on when it is said "they are spamming"
and there are lots of speculation about who they might be and why they are doing it.

[Quickseller]

I believe that you can use CPFP if you are the sender to the extent that your transaction sends change to an address whose private key(s) you control.

Technically speaking it should be possible, as long as you own the private key to one of the outputs in order to spend it.
But I didn't put it under "Sender" section because as a sender there are better options such as opt-in RBF.

I think it is worth mentioning here that Electrum will have CPFP feature in its new release (2. along with SegWit support.

I think that "better" is a fairly subjective term. I think it is probably fair to say that RBF is a fairly controversial "feature" and that some people may not want to utilize this feature because of these controversies.

I would point out that some companies/services are willing to accept 0/unconfirmed transactions under a certain set of circumstances, and I imagine that one criteria would likely be that the transaction in question is not a RBF transaction (nor does it depend on a RBF transaction that has < a certain number of confirmations). For example, Gemini will accept 0/unconfirmed deposits under an undisclosed set of circumstances (and with certain restrictions -- they also require identity verification prior to allowing users to use their exchange), and I imagine that they will not accept a RBF transaction that is 0/unconfirmed. 

[oxygen88]

That is a lot of useful information for people that are new to bitcoin, I never knew that we can accelerate the transaction using all these sites.

[Quickseller]

Can you please add a note to include the txid needing confirmation in the initial PM to me? I am receiving an increasing number of PMs asking for help every day, and it is becoming a hassle asking users for the txid in response to a message asking if I can help. This is especially true considering that the time I am able to devote to the forum is declining.

Thanks. 

If anyone knows of any other similar threads, please feel free to x-post the above quote.

[Coding Enthusiast]

Can you please add a note to include the txid needing confirmation in the initial PM to me? I am receiving an increasing number of PMs asking for help every day, and it is becoming a hassle asking users for the txid in response to a message asking if I can help. This is especially true considering that the time I am able to devote to the forum is declining.

Thanks. 

If anyone knows of any other similar threads, please feel free to x-post the above quote.

Added.

[maximprimus]

It's been 5 days for this transaction: 7994738a983be110f6d060f0500fc5b4ed369189a9946e80e65adf05ff40c7e2 and I'm trying to find out what I can do to cancel or resend it with a higher fee.

I'm using Bitcoin Core version v0.14.1 (64-bit)

I've read several posts about RBF and some different methods of replacing the transaction.  Most of them say to Abandon the transaction however this option is grayed out for me?

I read a post that said to close Bitcoin Core, delete mempool.dat, and restart with walletbroadcast=0 but it is still grayed out.

I'm not sure what else to do at this point.  Using one of the accelerator sites would work if I had any more BTC...

Are there any other options?

I really appreciate your help!

Thank you and have a great day.

[Dent_DC]

If you found any mistakes (technical or grammatical) please tell me.

This:

2) A very important thing to know
Transaction can be reversed until it is confrimed. in other words you do not own the received bitcoins until the transaction has at least 1 confirmation.

Should be confirmed.

This:

3) Ask a miner directly to mine your transaction, this may not be free.
You can use ViaBTC accelerator tool. Read the details on the ViaBTC website.

Dead link, should be https://viabtc.com/tools/txaccelerator/