When using checkpoint sync, only checkpoint state is available, block is
not downloaded and backfilled later.
`dag.backfill` tracks latest filled `slot`, and latest `parent_root` for
which no block has been synced yet.
In checkpoint sync, this assumption is broken, because there, the start
`dag.backfill.slot` is set based on checkpoint state slot, and the block
is also not available.
However, sync manager in backward mode also requests `dag.backfill.slot`
and `block_clearance` then backfills the checkpoint block once it is
synced. But, there is no guarantee that a peer ever sends us that block.
They could send us all parent blocks and solely omit the checkpoint
block itself. In that situation, we would accept the parent blocks and
advance `dag.backfill`, and subsequently never request the checkpoint
block again, resulting in gap inside blocks DB that is never filled.
To mitigate that, the assumption is restored that `dag.backfill.slot`
is the latest filled `slot`, and `dag.backfill.parent_root` is the next
block that needs to be synced. By setting `slot` to `tail.slot + 1` and
`parent_root` to `tail.root`, we put a fake summary into `dag.backfill`
so that `block_clearance` only proceeds once checkpoint block exists.
When using checkpoint sync, the initial block is missing in the DB.
Update the LC data collector initialization to account for that,
avoiding a spurious error message when it is incorrectly accessed:
```
ERR 2024-02-07 11:21:55.416+01:00 Block failed to load unexpectedly topics="chaindag_lc" bid=d30517a7:8257504 tail=8257504
```
Also fixes a regression from #5691 that resulted in similar messages
while importing the first few blocks after checkpoint sync.
Thanks to @arnetheduck for reporting this.
If the initial state replays cover the finalized head, import matching
`LightClientBootstrap` into database.
This also addresses this error when light client requests bootstrap from
the genesis slot on networks that launch with Altair enabled.
```
{"lvl":"DBG","ts":"2023-10-04 11:17:49.665+00:00","msg":"LC bootstrap unavailable: Sync committee branch not cached","topics":"chaindag_lc","slot":0}
```
Simplify best `LightClientUpdate` collection by tracking only canonical
data instead of tracking the best update across all branches within the
sync committee period.
- https://github.com/ethereum/consensus-specs/pull/3553
When creating new LC updates, information about the parent block's post
state must be available (cached), but information about current block's
post state is not yet required. Caching information about the current
block's post state can be delayed, simplifying the LC data collection
logic a bit and allowing more future flexibility with the cache design.
When new finality is reached without supermajority sync committee
support, trigger another event push on beacon-API and libp2p once
the finality gains supermajority support.
- https://github.com/ethereum/consensus-specs/pull/3549
Replace sections that need to be maintained with every `ConsensusFork`
related to LC data collection with a generic logic that keeps working
when unrelated parts of Ethereum change.
Directly initialize `ForkedLightClientObj` instead of separately first
setting the `kind` (initializing everything to zero) and then assigning
the forky data after that.
For symmetry with `forkyState` when using `withState`, and to avoid
problems with shadowing of `blck` when using `withBlck` in `template`,
also rename the injected `blck` to `forkyBlck`.
- https://github.com/nim-lang/Nim/issues/22698
Just the variable, not yet `lcDataForkAtStateFork` / `atStateFork`.
- Shorten comment in `light_client.nim` to keep line width
- Do not rename `stateFork` mention in `runProposalForkchoiceUpdated`.
- Do not rename `stateFork` in `getStateField(dag.headState, fork)`
Rest is just a mechanical mass replace
When using `--history=prune`, `dag.tail.slot` may advance beyond the
configured light client data retention period. Update the LC logic so
that the `dag.tail.slot` is no longer considered for LC pruning.
It is still considered to check whether new data can be produced.
To allow LC data retention longer than the one for historic states,
introduce persistent DB caches for `current_sync_committee` and
`LightClientHeader` for finalized epoch boundary blocks.
This way, historic `LightClientBootstrap` requests may still be honored
even after pruning. Note that historic `LightClientUpdate` requests are
already answered using fully persisted objects, so don't need changes.
Sync committees and headers are cached on finalization of new data.
For existing data, info is lazily cached on first access.
Co-authored-by: Jacek Sieka <jacek@status.im>
When the epoch boundary block is missed, we incorrectly assume that the
next couple blocks improve finality, leading to repeated pushes of the
same light client finality update and incorrectly ignoring some gossip.
Distinguish between those code locations that need to be updated on each
light client data format change, and those others that should generally
be fine, as long as a valid light client object is processed.
The former are tagged with static assert for `LightClientDataFork.high`.
The latter are changed to `lcDataFork > LightClientDataFork.None` to
indicate that they depend only on presence of any valid object.
Also bundled a few minor cleanups and fixes.
Also add `Forky` type for `LightClientStore` and minor fixes / cleanups.
The light client data structures were changed to accommodate additional
fields in future forks (e.g., to also hold execution data).
There is a minor change to the JSON serialization, where the `header`
properties are now nested inside a `LightClientHeader`.
The SSZ serialization remains compatible.
See https://github.com/ethereum/consensus-specs/pull/3190
and https://github.com/ethereum/beacon-APIs/pull/287
In a future fork, light client data will be extended with execution info
to support more use cases. To anticipate such an upgrade, introduce
`Forky` and `Forked` types, and ready the database schema.
Because the mapping of sync committee periods to fork versions is not
necessarily unique (fork schedule not in sync with period boundaries),
an additional column is added to `period` -> `LightClientUpdate` table.
* implement several capellaImplementationMissing points
* don't register validator activity for not-active validators
* don't check validator indices already coming out of committees which exist; must be active validators, or else other deeper bugs
When backfilling LC updates (`--light-client-data-import-mode=full`),
the highest participation update is computed without ensuring that the
finalized header is in the same period. Updates sharing same period for
both finalized and attested headers should be preferred.
Fixes a bug leading to suboptimal update selection.
Aligns the default retention policy for LC data with the one for blocks.
Minimum spec requirement for both blocks and LC data is ~5 months.
Additional use cases are better supported by retaining data for longer.
* merge LC db into main BN db
To treat derived LC data similar to derived state caches, merge it into
the main beacon node DB.
* shorten table names, group with lc prefix
* persist LC data across restarts
With the Altair spec `LightClientUpdate` structure taking its final form
it is finally possible to persist LC data across restarts without having
to worry about data migration due to spec changes. A separate `lcdataV1`
database is created in the `caches` subdirectory to hold known LC data.
A full database with default settings (129 periods) uses <15 MB disk.
* extend LC data DB rationale
* wording
* add `isSupportedBySQLite` helper and explicit return
* remove redundant `return`
Separate LC initialization options from the main ChainDAGRef options to
allow ChainDAGRef to treat them as opaque and reduce risk for conflicts
when extending those options in the future.
Merkle proofs tend to have long underlying type definitions, e.g.,
`array[log2trunc(NEXT_SYNC_COMMITTEE_INDEX), Eth2Digest]`. For the
ones used in the LC sync protocol, dedicated types are introduced
to improve readability. Furthermore, the `CachedLightClientBootstrap`
wrapper that solely wrapped a merkle branch is eliminated.
Adds a `--light-client-data-max-periods` option to override the number
of sync committee periods to retain light client data.
Raising it above the default enables archive nodes to serve full data.
Lowering below the default speeds up import times (still no persistence)
Etan Kissling
tersec
zah
Miran
Jacek Sieka