Update 5_2_Resending_a_Transaction_with_RBF.md

5_2_Resending_a_Transaction_with_RBF.md

@@ -2,45 +2,70 @@
 
 > **NOTE:** This is a draft in progress, so that I can get some feedback from early reviewers. It is not yet ready for learning.
 
-Sometimes a Bitcoin transaction can get stuck. Usually it's because there wasn't sufficient transaction fee, but it can also be because of a one-time network or software glitch.
+If your Bitcoin transaction is stuck, and you're sender, you can resend it using RBF (replace-by-fee).
 
-## Watch for Stuck Transactions
+> **VERSION WARNING:** This is an innovation from Bitcoin Core v 0.12.0, which means that by now most miners should be using it. However, it only reached full maturity in the Bitcoin core wallet, with the `bumpfee` command in 
 
-You should _always_ watch to ensure that your transactions go out. `bitcoin-cli listunspent` will show all of your incoming and outgoing transactions, while `bitcoin-cli gettransaction` with a txid will show a specific transaction. 
+## Opt-In for RBF
 
-The following shows a transaction that has not been put into a block. Note that it has no confirmations. 
+RBF is an opt-in Bitcoin feature. Transactions are only eligible for using RBF if they've been created with a special RBF flag. This is done by setting their sequence number (which is typically set automatically, so that it's more than 0 and less than 0xffffffff (4294967295).
+
+This is simply done by adding a `sequence` variable to the vins:
 ```
-$ bitcoin-cli gettransaction 0f618e38efe887028a5dd04d0e12241431978b4de32f70308c13a114d7cfcbd2
+$ rawtxhex=$(bitcoin-cli -named createrawtransaction transactions='''[ { "txid": "'$utxo_txid'", "vout": '$utxo_vout', "sequence": 1 } ]''' outputs='''{ "'$recipient'": 2.9, "'$changeaddress'": 1.0 }''')
+```
+You should of course sign and send your transaction as usual:
+```
+$ signedtx=$(bitcoin-cli -named signrawtransaction hexstring=$rawtxhex | jq -r '.hex')
+$ bitcoin-cli -named sendrawtransaction hexstring=$signedtx
+4075dbf84303c01adcb0b36cd2c164e2b447192c2d9fbf5fde3b99d0ac7e64b6
+```
+Now, when you look at your transaction, you should see something new: the `bip125-replaceable` line, which has always been marked `no` before, is now marked `yes`:
+```
+$ bitcoin-cli gettransaction 4075dbf84303c01adcb0b36cd2c164e2b447192c2d9fbf5fde3b99d0ac7e64b6
 {
-  "amount": -0.84927000,
-  "fee": -0.00000400,
+  "amount": -2.90000000,
+  "fee": 0.00000000,
   "confirmations": 0,
   "trusted": true,
-  "txid": "0f618e38efe887028a5dd04d0e12241431978b4de32f70308c13a114d7cfcbd2",
+  "txid": "4075dbf84303c01adcb0b36cd2c164e2b447192c2d9fbf5fde3b99d0ac7e64b6",
   "walletconflicts": [
   ],
-  "time": 1491588722,
-  "timereceived": 1491588722,
-  "bip125-replaceable": "no",
+  "time": 1491597044,
+  "timereceived": 1491597044,
+  "bip125-replaceable": "yes",
   "details": [
     {
       "account": "",
       "address": "n2eMqTT929pb1RDNuqEnxdaLau1rxy3efi",
       "category": "send",
-      "amount": -0.84927000,
+      "amount": -2.90000000,
       "vout": 0,
-      "fee": -0.00000400,
+      "fee": 0.00000000,
       "abandoned": false
     }
   ],
-  "hex": "0200000001c6cb05c5212bb7ec14add72883a17f0a68aa399354bc2f7cf02df6e7d68a6937000000006a47304402203f21d769cbf3cf1626ef09bb35d0d8e88efe9f14d097f4b493628e96b2e1c90b0220162ff60701525e70942f5090dc48ec2b2f3b87cd40185351ab316991567f61c50121029045eaa55d283526c723e6d5495d9b3f077b545563f86465aafcd9bfdd50359effffffff0118e20f05000000001976a914e7c1345fc8f87c68170b3aa798a956c2fe6a9eff88ac00000000"
+  "hex": "020000000100e3da9fa8b5368dd383ebabb820ae257d8f19bb1a9e3fb36f6c3e1b83e6d0f3000000006b483045022100950af7346a5bff5546627b6e9379573cb7e56420d6187f90a8b7aab8fcad730502200c4e66b96b499fec020f9397861bda765c29ec873fc8e61f85a32c73e650173b0121031008e55d06d25bb2acdf85395fe4c2df28492325d8ffc3734a2dc372436b6a330100000002800c4911000000001976a914e7c1345fc8f87c68170b3aa798a956c2fe6a9eff88ac00e1f505000000001976a914d83b41b8f67b31310bb487b66d859a6d0a92682c88ac00000000"
 }
 ```
-A transaction can be considered stuck if it stays in this state for an extended amount of time. Not too many years ago, you could be sure it would go out _eventually_. But, that's nolonger the case due to the increased usage of the Bitcoin network. Now, if a Bitcoin transaction is stuck for too long, it will eventually drift out of the mempool, and then it will _never_ get placed in a block.
+The `bip125-replaceable` flag will stay `yes` until the transaction receives confirmations. At that point it is no longer replacable.
 
-_What is the mempool?_ The Bitcoin mempool (or Memory Pool) is the pool of all the unconfirmed transactions. Miners pull from it 
+_Should I trust transactions with no confirmations?_ No, never. This was true before RBF and it was true after RBF. Transactions must receive confirmations before they are trustworthy. This is especially true if a transaction is marked as `bip125-replaceable`, becausethen it can be ... replaced.
 
-## Set Your Transaction Fee
+### Optional: Always Opt-In for RBF
 
-1. Abandon, then rebuild, fulfilling all outputs
-2. Use bumpfee
+If you prefer, you can _always_ opt in for RBF. Do so by running your `bitcoind` with the `-walletrbf` command or simply adding it to your bitcoin.conf file:
+```
+walletrbf=1
+```
+Once you've done this (and restarted your `bitcoind`), then all transactions should have a lower sequence number and be marked as `bip125-replaceable`.
+
+## Replace a Transaction the Hard Way: By Hand
+
+### Use RBF Wisely
+
+-low to high transaction fees
+-combine transactions
+
+## Replace a Transaction the Easy Way: By bumpfee
+It doesn't solve the same problem. Core devs are looking for compressing transactions, not necessarily adding fees alone.