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RE: Do forks with fallback - my HF21 wish
rollback will not be possible if there are changes to the blockchain (database schema) and it will require complete replay.
rollback will not be possible if there are changes to the blockchain (database schema) and it will require complete replay.
Not entirely. We did it just last week, and only had to go back to the last good headblock.
I was not able to reply because of lack of "MANA"
I was not around, but from what I understand it was from a minor version to another minor version. It was a Soft fork and not a hardfork which often includes changes to the "consensus" logic and also to the format/schema in which blockchain snapshots are stored. Part of the blockchain state from many plugins are now stored to rocksdb. So a restart is possible without replay in cases where schema and the consensus is not changed.
I believe eventually STEEM is heading to a model where only the consensus related data will be on the immutable blockchain and rest will be in various databases.
Also, I need to elaborate on the "roll back" - generally roll back means going back to the earlier state. So what I meant to say is that is complete re-index will be needed if there are changes to the consensus state. Roll back will be against the "immutable nature" of the blockchains. TheDAO attack on the Etherium chain is probably the best example where the immutability was not touched and forks were brought into fix the issues (with the smart contract) : https://ethereum.github.io/blog/2016/06/17/critical-update-re-dao-vulnerability/
I am not sure how this was done - blocks after the last-good-head-block was ignored ?
You aren't wrong, at all about any of your assessment, past or present.
Except, there was a fork from mixed node versions, leading to a split chain, aka an actual unintended fork. We DID roll back to a checkpoint block and restarted the chain, quickly, and lost transactions (reversed,as if they never happened) so if we do it fast enough (too late now because way too much to undo), it is not entirely impossible.
oh, I was not aware of this - interesting scenario. Thank you for explaining.... This sounds like a classic Byzantine generals scenario.
Careful, we might sound smart and able to code and NEVER make the top 20...
Oh, everything I said above was bluffing ... There are infinite parallel blockchains and infinite number of top 20s ... as people from this chain and has done more hard freezes, i mean forks than every other blockchain in the known universe of blockchains put together, the immutable genesis blocks of all the chains will bless us with infinite amounts of mana ... the super intellectual state machines using probabilistic methods to maintain inter galactic consensus will help us with intelligence to even understand the meaning of 42 .... believe in Satoshi .. don't fear .. Amen! Aham Brahamasmi.
When I am not bluffing I speak like this. Will this help ?
PS: 42 is the "Answer to the Ultimate Question of Life, the Universe, and Everything" in The Hitchhiker's Guide to the Galaxy books.
If you weren't married with a new baby on top of all you do here (congratulations on the baby again), I might change my sexual persuasion and hit on you, just on the sheer awesomeness of that comment and the fact you own 2000 banana plants and know how to prep a jackfruit.