Deposit transaction pending in mempool and CPFP

WORK IN PROGRESS

The following article is directed at users who have extensive knowledge of Bitcoin, and understand the nuances of the suggestions below. It is not advised to try one's luck as unforeseen consequences might happen.

Basic fee considerations

A trade on Bisq can only start after the deposit transaction has been mined into a block (one confirmation is enough), so the application will choose the optimal miner fee based on how mempool is busy at the moment the taker accepts the maker's offer. There are two different edge cases which Bisq is not able to account for, and that will delay the first confirmation, if not prevent it entirely from happening:

• sudden spikes of transactions in mempool (think when central exchanges decide to flood the blockchain with consolidation txs, or a new hype like inscriptions takes off)
• traders funding Bisq wallet at a fee which is too low to be confirmed in current mempool, and then using the unconfirmed utxo to fund the deposit tx (this will cause a Child Pays For Parent on the original funding tx -and possible unconfirmed precursors- that will decrease the effective fee rate of the actual deposit transaction)

Commonly, it is a combination of the two that happens: mempool becomes progressively busier, and one of the traders (or even worse, both) send funds from an external wallet to be used for the deposit transaction, selecting an inadequate fee that will bring down the effective fee rate.