lets assume block 455300 is orphaned and it contained tx1 and tx2.
block 455300 is mined by another miner and that is the longest chain.
it contains tx1 and tx3
- is that possible?
- what will happen to tx2? will it exist in memory pool or disappears?
When a node dumps an orphaned block, its transactions are returned to the list of unconfirmed transactions, unless it has already been included in a block in the new chain.
So, in your example,
tx1 is still confirmed, but
tx2 is no longer confirmed and is available to be included in the next block.