This pull request ports some changes from the main state snapshot
integration one, specifically introducing the flat state tracking in
pathdb.
Note, the tracked flat state changes are only held in memory and won't
be persisted in the disk. Meanwhile, the correspoding state retrieval in
persistent state is also not supported yet. The states management in
disk is more complicated and will be implemented in a separate pull
request.
Part 1: https://github.com/ethereum/go-ethereum/pull/30752
This pull request removes the destruct flag from the state snapshot to
simplify the code.
Previously, this flag indicated that an account was removed during a
state transition, making all associated storage slots inaccessible.
Because storage deletion can involve a large number of slots, the actual
deletion is deferred until the end of the process, where it is handled
in batches.
With the deprecation of self-destruct in the Cancun fork, storage
deletions are no longer expected. Historically, the largest storage
deletion event in Ethereum was around 15 megabytes—manageable in memory.
In this pull request, the single destruct flag is replaced by a set of
deletion markers for individual storage slots. Each deleted storage slot
will now appear in the Storage set with a nil value.
This change will simplify a lot logics, such as storage accessing,
storage flushing, storage iteration and so on.
rjl493456442