Quote from: pooya87 on Today at 05:25:12 AM

Quote from: xmready on Today at 05:06:37 AM

I don't quite understand this. It feels like I'm missing prerequisite knowledge about what validation is exactly. I wonder if these empty blocks become stale or are part of the official block chain, and why do miners do it. Where can I learn more so as to decipher the meaning of this?

The correct way of doing things is that the miner seeing the new block downloads that block and verifies it and updates its UTXO database. Then if it were valid the miner builds the next block on top of that valid block.

Some miners try to save a tiny amount of time by "spying" on other miners. For example they connect a fake miner to the other mining pools and as the other pool finds a new block their fake miner receives that "hash" of that block which is small (32 bytes only) then the "spy" miner builds their next block based on that hash alone without verifying if the block that was found by the other pool was valid or not (which it may not be valid and during a upgrade/fork the chances of it are higher and that would create a longer stale chain with 2 blocks in it, if more miners do the same this stale chain can become longer).

An indication of this type of mining is empty blocks because when the spy miner hasn't validated the previous block it can not update its UTXO database and doesn't know which transactions were in the previous block (and can't be in the block they mine) so they set their next block to be empty first until they update their UTXO database.

I think in general, an empty block is probably the result of a miner not validating a block prior to building on top of it. However, updating the UTXO database will take precious seconds from a miner, so it is possible that a miner would have the following workflow:
*Receive block
*Validate block (2)
*start building on top of the validated block that is empty (3)
*update UTXO set
*start building on top of the validated block that contains transactions that spend from the updated UTXO set.

I also suspect that some miners may change the order of 2 and 3 depending on which pool mined the previous block.