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Using geth, I've setup a testnet and some accounts, and tried some transactions. I see that I have to unlock the account, send a transaction, and start mining to get it into the blockchain. Being lazy, I thought I would just leave mining ON. But when mining, I see blocks being generated amongst the many other messages flying by. This seemed wasteful, since the few transactions I would be experimenting with would only fill up a block or two, and I wanted to see what I was typing in the console. So I thought I would set up peers, and use one geth node for playing with transactions, and another for mining so that transactions would be immediately recorded. But when I started mining in the mining node, I see a constant stream of block related messages:
INFO [01-30|14:28:53] Successfully sealed new block number=356 hash=c3ec55…74c842 INFO [01-30|14:28:53] 🔗 block reached canonical chain number=351 hash=28bbf5…5bb124 INFO [01-30|14:28:53] 🔨 mined potential block number=356 hash=c3ec55…74c842 INFO [01-30|14:28:53] Commit new mining work number=357 txs=0 uncles=0 elapsed=140.751µs INFO [01-30|14:28:54] Successfully sealed new block number=357 hash=b5cd91…e3acb7 INFO [01-30|14:28:54] 🔗 block reached canonical chain number=352 hash=5bdd6b…6e1f25 INFO [01-30|14:28:54] 🔨 mined potential block number=357 hash=b5cd91…e3acb7 INFO [01-30|14:28:54] Commit new mining work number=358 txs=0 uncles=0 elapsed=184.095µs INFO [01-30|14:28:54] Successfully sealed new block number=358 hash=58169e…320222 INFO [01-30|14:28:54] 🔗 block reached canonical chain number=353 hash=bbd482…92ffd0 INFO [01-30|14:28:54] Mining too far in the future wait=2s INFO [01-30|14:28:54] 🔨 mined potential block number=358 hash=58169e…320222
So is this normal? Why are so many potential blocks needed? What's up with the future thing? (I checked my time against time.is (from another ethSE answer) and I'm within 0.2 seconds.)
Thanks for any insight or guidance.