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[NC-2233] Randomly perform full validation when fast syncing blocks #770
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ajsutton
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mbaxter
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Feb 5, 2019
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| import tech.pegasys.pantheon.ethereum.mainnet.HeaderValidationMode; | ||
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| public interface ValidationPolicy { |
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Might be worth adding @FunctionalInterface here
| boolean seenLight = false; | ||
| boolean seenFull = false; | ||
| // It's theoretically possible to flip a coin 2^31-1 times and only ever get heads but | ||
| // we're probably more likely to get intermittent failures from the hard drive failing... |
…c-extra-validation
…c-extra-validation
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PR description
During a fast sync, most blocks skip proof of work validation to speed up import. However we randomly select blocks to perform full validation on so we have confidence it really is a valid chain.
There's a slight oddity here because of the way we've modelled header validation - we actually perform header validation in two separate places, when the header is downloaded (detached - parent may not have been imported yet) and when it's about to be imported (attached - it's parent block is already on our chain). This means we have two independent places where we decide on the type of validation. With this implementation, fast sync is randomly selecting light or full separately at both those points. There is actually only ever one rule skipped by using light validation -
ProofOfWorkValidationwhen using ethash orIbftCommitSealsValidationRulewhen using IBFT.ProofOfWorkValidationruns with the detached rules,IbftCommitSealsValidationRuleruns with the attached rules. Net result, when using ethash the choice between full or light only makes a difference when running the detached rules and for IBFT it only makes a difference when running the attached rules.