In response to your description (having issues whereas syncing full node), I ponder in case your “unconfirmed transaction” is absolutely unconfirmed? Is it already confirmed, or discarded (attributable to double-spending and so forth)?

The primary downside: “caught” 0-confirmation transaction

To begin with, replace-by-fee is there to cope with “low-fee caught transactions” downside, you’ll have the ability to bump charge with ease if the transaction had RBF enabled.

In case your caught transaction is just not so pressing, it’s possible you’ll simply await the mempool to be cleared naturally, then your transaction will lastly be confirmed, because the mempool is just not so crowded (like previous occasions in 2017) these days.

Simply watch the final “Mempool dimension in MB” chart right here: https://core.jochen-hoenicke.de/queue/#24h

If you wish to “speed up” or “revert” this transaction, you’ve two choices.

The primary possibility: it’s possible you’ll contact a mining pool which gives “transaction accelerating (prioritising)” service, like Poolin or BTC.COM. Nonetheless, this selection will be costly, and, there will not be any refund.

The second possibility: “double-spend” by your self with Electrum, which is often less expensive than transaction prioritising providers talked about above, however a bit sophisticated.

1. Discover out the earlier transaction(s) which the caught transaction is spending from. Chances are you’ll use the getrawtransaction STUCK_TXID true (exchange STUCK_TXID with your personal caught transaction ID) command in debug console of Bitcoin Core, or simply question it on a web-based block explorer like https://blockstream.information.

   Blockstream explorer exhibits earlier outpoints clearly, the place the outpoint is represented in TXID(lengthy alphanumeric textual content string):INDEX(quantity) format. For instance: this transaction spent 2 earlier transactions, which have TXIDs of 00f5854cebdcd318edd325ab07e4157964f225a659302f3f5949ffe07020db4e and 6d4a34592200324f716a92d8d84db8c85bc97189610b1d4bee4fcb7d56713857

2. Copy uncooked transaction knowledge of earlier transaction(s). Chances are you’ll merely double-click every transaction confirmed on Bitcoin Core GUI in flip, to search out them by transaction ID, after which right-click -> Copy uncooked transaction.

   You might also use the getrawtransaction PREVIOUS_TXID command as a substitute, you want to run this command individually on every PREVIOUS_TXID, if a number of earlier transactions have been spent.

3. Create a brand new Electrum pockets on an offline system, then select the Import Bitcoin addresses or non-public keys possibility.

4. Import your non-public keys to Electrum. The pockets will not sync, as a result of there is not any web – that is high quality, as a result of we do not need Electrum to fetch again the caught transaction.

5. Import the earlier transaction(s) by clicking Instruments menu -> Load transaction -> From textual content.

6. Click on the View menu -> Present Cash to point out the Cash tab. Then change to the Cash tab, choose all of them, and right-click -> Spend.

   In fact, if you’re certain about precisely which cash have been spent, you will not must spend all accessible cash this time, which might scale back the charge value a bit – however this case is comparatively uncommon. To maintain your self from off-by-one human errors, you’d higher simply spend all of them.

7. Now, you might be about to assemble a double-spending transaction which can ship these cash again to your personal pockets, or some other tackle(es) you need, by clicking Preview button. This time you must select a better charge charge (sat/Byte), no less than greater than the caught transaction.

   By the best way, it’s extremely beneficial to allow replace-by-fee on this transaction, in case of additional fee-bumping.

8. Electrum is ready to present QR code of this double-spending transaction. Use one other on-line system to scan it with Electrum, then it might be despatched out. You might also attempt to ship it instantly after reconnecting the system to Web.
   If the caught transaction has not but expired on the Electrum server you might be utilizing, broadcasting the double-spending transaction would possibly face some errors. Chances are you’ll attempt to broadcast it by means of different strategies, eg. block explorers, and sendrawtransaction of Bitcoin Core.

The second downside: Bitcoin Core full node is painful to sync

First, the efficiency bottleneck often lies at frequent I/O operations on the chainstate subdirectory, which shops the UTXO database, particularly the info listing was positioned on an HDD (which is meant to make the scenario worse if the HDD is SMR).

Second, at present, I am personally not in favor of pruning, as a result of virtually all historic transaction historical past (which is strictly what the large block chain incorporates) is discarded, thus rescanning turns into restricted inside current blocks solely. Rescanning occurs if you’re importing keys/addresses/pockets.dat, or zapwallettxes. Sooner or later, this downside is perhaps lastly relieved by some enhancements.

In case your laptop has loads of accessible RAM, it’s possible you’ll allocate greater than 6GB (depends upon historic peak UTXO dimension) of RAM for the database cache (see the Choices window) of Bitcoin Core. This tweak successfully removes the I/O bottleneck. (effectively, you should still face this downside if you’re catching up from some date earlier than, it’s possible you’ll cat (Linux/Mac) or kind all recordsdata (use the * wildcard) into /dev/null (Linux/Mac) or nul (Home windows) to drive the OS to learn them as soon as, then they might be cached into the RAM)

When you have each HDD and SSD, you may configure the blocksdir parameter emigrate the large block chain to a cheap-but-slow HDD, whereas preserving the frequently-accessed chainstate and so forth on a fast-but-expensive SSD.