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 introduces a state.Reader interface for state
accessing.
The interface could be implemented in various ways. It can be pure trie
only reader, or the combination of trie and state snapshot. What's more,
this interface allows us to have more flexibility in the future, e.g.
the
archive reader (for accessing archive state).
Additionally, this pull request removes the following metrics
- `chain/snapshot/account/reads`
- `chain/snapshot/storage/reads`