user59174: Except for checking for double spends, if there's a transaction in a block that's already in the node's mempool, it can theoretically skip its validation. Does it actually happen, or the nodes validate each transaction twice?

user24925: The most expensive part of checking a transaction, ECDSA validation, is cached. 

59174: <p>Except for checking for double spends, if there's a transaction in a block that's already in the node's mempool, it can theoretically skip its validation. Does it actually happen, or the nodes validate each transaction twice?</p>
 24925: <p>The most expensive part of checking a transaction, ECDSA validation, is cached. </p>
