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Is it possible for transactions not to be processed with low Gwei? Or will always be processed just will take some time?
Assume I do 1000s of transactions with 1 Gwei, can I rest assured that all transactions will be processed 100%, being the only down side that I have to wait a bit more?
Or I have the risk that some of them may not be processed?
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As per my understanding, It depends on how long you would like to stay. You can't exactly say whether it will not be processed, but if there are enough transactions willing to pay a higher gas price, your transaction gets a lower priority and there is no guarantee that it will be mined with in this amount of time. But it will stay in the pending transaction pool until it's mined. But that staying time is comparatively larger then it's more like a transaction that's not gonna be executed.
Anyway you can increase the gas price by re-sending the transaction with the same nonce which will give it more chance to be mined. However transactions from one account are mined sequentially and hence other transactions you send from the same account afterwards will not be mined until the previous is mined
This question and these reddit and github links might help you for a better understanding.
