## Proposed Changes
Cache the total active balance for the current epoch in the `BeaconState`. Computing this value takes around 1ms, and this was negatively impacting block processing times on Prater, particularly when reconstructing states.
With a large number of attestations in each block, I saw the `process_attestations` function taking 150ms, which means that reconstructing hot states can take up to 4.65s (31 * 150ms), and reconstructing freezer states can take up to 307s (2047 * 150ms).
I opted to add the cache to the beacon state rather than computing the total active balance at the start of state processing and threading it through. Although this would be simpler in a way, it would waste time, particularly during block replay, as the total active balance doesn't change for the duration of an epoch. So we save ~32ms for hot states, and up to 8.1s for freezer states (using `--slots-per-restore-point 8192`).
## Proposed Changes
Implement the consensus changes necessary for the upcoming Altair hard fork.
## Additional Info
This is quite a heavy refactor, with pivotal types like the `BeaconState` and `BeaconBlock` changing from structs to enums. This ripples through the whole codebase with field accesses changing to methods, e.g. `state.slot` => `state.slot()`.
Co-authored-by: realbigsean <seananderson33@gmail.com>
* Remove redundant method
* Pull out a method out of a struct
* More precise db access abstractions
* Move fake trait method out of it
* cargo fmt
* Fix compilation error after refactoring
* Move another fake method out the Store trait
* Get rid of superfluous method
* Fix refactoring bug
* Rename: SimpleStoreItem -> StoreItem
* Get rid of the confusing DiskStore type alias
* Get rid of SimpleDiskStore type alias
* Correction: A method took both self and a ref to Self
* Start updating types
* WIP
* Signature hacking
* Existing EF tests passing with fake_crypto
* Updates
* Delete outdated API spec
* The refactor continues
* It compiles
* WIP test fixes
* All release tests passing bar genesis state parsing
* Update and test YamlConfig
* Update to spec v0.10 compatible BLS
* Updates to BLS EF tests
* Add EF test for AggregateVerify
And delete unused hash2curve tests for uncompressed points
* Update EF tests to v0.10.1
* Use optional block root correctly in block proc
* Use genesis fork in deposit domain. All tests pass
* Cargo fmt
* Fast aggregate verify test
* Update REST API docs
* Cargo fmt
* Fix unused import
* Bump spec tags to v0.10.1
* Add `seconds_per_eth1_block` to chainspec
* Update to timestamp based eth1 voting scheme
* Return None from `get_votes_to_consider` if block cache is empty
* Handle overflows in `is_candidate_block`
* Revert to failing tests
* Fix eth1 data sets test
* Choose default vote according to spec
* Fix collect_valid_votes tests
* Fix `get_votes_to_consider` to choose all eligible blocks
* Uncomment winning_vote tests
* Add comments; remove unused code
* Reduce seconds_per_eth1_block for simulation
* Addressed review comments
* Add test for default vote case
* Fix logs
* Remove unused functions
* Meter default eth1 votes
* Fix comments
* Address review comments; remove unused dependency
* Disable/delete two outdated tests
* Bump eth1 default vote warn to error
* Delete outdated eth1 test
Co-authored-by: Pawan Dhananjay <pawandhananjay@gmail.com>
* Implement freezer database for state vectors
* Improve BeaconState safe accessors
And fix a bug in the compact committees accessor.
* Banish dodgy type bounds back to gRPC
* Clean up
* Switch to exclusive end points in chunked vec
* Cleaning up and start of tests
* Randao fix, more tests
* Fix unsightly hack
* Resolve test FIXMEs
* Config file support
* More clean-ups, migrator beginnings
* Finish migrator, integrate into BeaconChain
* Fixups
* Fix store tests
* Fix BeaconChain tests
* Fix LMD GHOST tests
* Address review comments, delete 'static bounds
* Cargo format
* Address review comments
* Fix LMD ghost tests
* Update to spec v0.9.0
* Update to v0.9.1
* Bump spec tags for v0.9.1
* Formatting, fix CI failures
* Resolve accidental KeyPair merge conflict
* Document new BeaconState functions
* Fix incorrect cache drops in `advance_caches`
* Update fork choice for v0.9.1
* Clean up some FIXMEs
* Fix a few docs/logs
* Update for new builder paradigm, spec changes
* Freezer DB integration into BeaconNode
* Cleaning up
* This works, clean it up
* Cleanups
* Fix and improve store tests
* Refine store test
* Delete unused beacon_chain_builder.rs
* Fix CLI
* Store state at split slot in hot database
* Make fork choice lookup fast again
* Store freezer DB split slot in the database
* Handle potential div by 0 in chunked_vector
* Exclude committee caches from freezer DB
* Remove FIXME about long-running test
