8e581601d6
If tower is full, old votes are evicted from the front of the deque: https://github.com/solana-labs/solana/blob/2074e407c/programs/vote/src/vote_state/mod.rs#L367-L373 whereas recent votes if expire are evicted from the back: https://github.com/solana-labs/solana/blob/2074e407c/programs/vote/src/vote_state/mod.rs#L529-L537 As a result, from a single tower_index scalar, we cannot infer which crds-vote should be overwritten: https://github.com/solana-labs/solana/blob/2074e407c/core/src/crds_value.rs#L576 In addition there is an off by one bug in the existing code. tower_index is bounded by MAX_LOCKOUT_HISTORY - 1: https://github.com/solana-labs/solana/blob/2074e407c/core/src/consensus.rs#L382 So, it is at most 30, whereas MAX_VOTES is 32: https://github.com/solana-labs/solana/blob/2074e407c/core/src/crds_value.rs#L29 Which means that this branch is never taken: https://github.com/solana-labs/solana/blob/2074e407c/core/src/crds_value.rs#L590-L593 so crds table alwasys keeps 29 **oldest** votes by wallclock, and then only overrides the 30st one each time. (i.e a tally of only two most recent votes).