Drop HeadTracker

Author: dapplion

beacon_node/beacon_chain/src/beacon_chain.rs

@@ -30,7 +30,6 @@ use crate::eth1_finalization_cache::{Eth1FinalizationCache, Eth1FinalizationData
 use crate::events::ServerSentEventHandler;
 use crate::execution_payload::{get_execution_payload, NotifyExecutionLayer, PreparePayloadHandle};
 use crate::fork_choice_signal::{ForkChoiceSignalRx, ForkChoiceSignalTx, ForkChoiceWaitResult};
-use crate::head_tracker::HeadTracker;
 use crate::historical_blocks::HistoricalBlockError;
 use crate::light_client_finality_update_verification::{
     Error as LightClientFinalityUpdateError, VerifiedLightClientFinalityUpdate,
@@ -53,7 +52,6 @@ use crate::observed_blob_sidecars::ObservedBlobSidecars;
 use crate::observed_block_producers::ObservedBlockProducers;
 use crate::observed_operations::{ObservationOutcome, ObservedOperations};
 use crate::observed_slashable::ObservedSlashable;
-use crate::persisted_beacon_chain::{PersistedBeaconChain, DUMMY_CANONICAL_HEAD_BLOCK_ROOT};
 use crate::persisted_fork_choice::PersistedForkChoice;
 use crate::pre_finalization_cache::PreFinalizationBlockCache;
 use crate::shuffling_cache::{BlockShufflingIds, ShufflingCache};
@@ -113,9 +111,7 @@ use std::marker::PhantomData;
 use std::sync::Arc;
 use std::time::{Duration, Instant};
 use store::iter::{BlockRootsIterator, ParentRootBlockIterator, StateRootsIterator};
-use store::{
-    DatabaseBlock, Error as DBError, HotColdDB, KeyValueStore, KeyValueStoreOp, StoreItem, StoreOp,
-};
+use store::{DatabaseBlock, Error as DBError, HotColdDB, KeyValueStore, StoreOp};
 use task_executor::{ShutdownReason, TaskExecutor};
 use tokio_stream::Stream;
 use tree_hash::TreeHash;
@@ -446,8 +442,6 @@ pub struct BeaconChain<T: BeaconChainTypes> {
     /// A handler for events generated by the beacon chain. This is only initialized when the
     /// HTTP server is enabled.
     pub event_handler: Option<ServerSentEventHandler<T::EthSpec>>,
-    /// Used to track the heads of the beacon chain.
-    pub(crate) head_tracker: Arc<HeadTracker>,
     /// A cache dedicated to block processing.
     pub(crate) snapshot_cache: TimeoutRwLock<SnapshotCache<T::EthSpec>>,
     /// Caches the attester shuffling for a given epoch and shuffling key root.
@@ -609,9 +603,6 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
     pub fn persist_head_and_fork_choice(&self) -> Result<(), Error> {
         let mut batch = vec![];
 
-        let _head_timer = metrics::start_timer(&metrics::PERSIST_HEAD);
-        batch.push(self.persist_head_in_batch());
-
         let _fork_choice_timer = metrics::start_timer(&metrics::PERSIST_FORK_CHOICE);
         batch.push(self.persist_fork_choice_in_batch());
 
@@ -620,31 +611,6 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
         Ok(())
     }
 
-    /// Return a `PersistedBeaconChain` without reference to a `BeaconChain`.
-    pub fn make_persisted_head(
-        genesis_block_root: Hash256,
-        head_tracker: &HeadTracker,
-    ) -> PersistedBeaconChain {
-        PersistedBeaconChain {
-            _canonical_head_block_root: DUMMY_CANONICAL_HEAD_BLOCK_ROOT,
-            genesis_block_root,
-            ssz_head_tracker: head_tracker.to_ssz_container(),
-        }
-    }
-
-    /// Return a database operation for writing the beacon chain head to disk.
-    pub fn persist_head_in_batch(&self) -> KeyValueStoreOp {
-        Self::persist_head_in_batch_standalone(self.genesis_block_root, &self.head_tracker)
-    }
-
-    pub fn persist_head_in_batch_standalone(
-        genesis_block_root: Hash256,
-        head_tracker: &HeadTracker,
-    ) -> KeyValueStoreOp {
-        Self::make_persisted_head(genesis_block_root, head_tracker)
-            .as_kv_store_op(BEACON_CHAIN_DB_KEY)
-    }
-
     /// Load fork choice from disk, returning `None` if it isn't found.
     pub fn load_fork_choice(
         store: BeaconStore<T>,
@@ -1338,11 +1304,14 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
     ///
     /// Returns `(block_root, block_slot)`.
     pub fn heads(&self) -> Vec<(Hash256, Slot)> {
-        self.head_tracker.heads()
+        todo!();
+        // self.head_tracker.heads()
     }
 
+    /// Only used in tests
     pub fn knows_head(&self, block_hash: &SignedBeaconBlockHash) -> bool {
-        self.head_tracker.contains_head((*block_hash).into())
+        let block_hash = (*block_hash).into();
+        self.heads().iter().any(|head| head.0 == block_hash)
     }
 
     /// Returns the `BeaconState` at the given slot.
@@ -3533,9 +3502,6 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
                 );
             });
 
-        self.head_tracker
-            .register_block(block_root, parent_root, slot);
-
         metrics::stop_timer(db_write_timer);
 
         metrics::inc_counter(&metrics::BLOCK_PROCESSING_SUCCESSES);

beacon_node/beacon_chain/src/builder.rs

@@ -5,7 +5,6 @@ use crate::eth1_chain::{CachingEth1Backend, SszEth1};
 use crate::eth1_finalization_cache::Eth1FinalizationCache;
 use crate::fork_choice_signal::ForkChoiceSignalTx;
 use crate::fork_revert::{reset_fork_choice_to_finalization, revert_to_fork_boundary};
-use crate::head_tracker::HeadTracker;
 use crate::migrate::{BackgroundMigrator, MigratorConfig};
 use crate::persisted_beacon_chain::PersistedBeaconChain;
 use crate::shuffling_cache::{BlockShufflingIds, ShufflingCache};
@@ -87,7 +86,6 @@ pub struct BeaconChainBuilder<T: BeaconChainTypes> {
     event_handler: Option<ServerSentEventHandler<T::EthSpec>>,
     slot_clock: Option<T::SlotClock>,
     shutdown_sender: Option<Sender<ShutdownReason>>,
-    head_tracker: Option<HeadTracker>,
     validator_pubkey_cache: Option<ValidatorPubkeyCache<T>>,
     spec: ChainSpec,
     chain_config: ChainConfig,
@@ -129,7 +127,6 @@ where
             event_handler: None,
             slot_clock: None,
             shutdown_sender: None,
-            head_tracker: None,
             validator_pubkey_cache: None,
             spec: TEthSpec::default_spec(),
             chain_config: ChainConfig::default(),
@@ -317,10 +314,6 @@ where
 
         self.genesis_block_root = Some(chain.genesis_block_root);
         self.genesis_state_root = Some(genesis_block.state_root());
-        self.head_tracker = Some(
-            HeadTracker::from_ssz_container(&chain.ssz_head_tracker)
-                .map_err(|e| format!("Failed to decode head tracker for database: {:?}", e))?,
-        );
         self.validator_pubkey_cache = Some(pubkey_cache);
         self.fork_choice = Some(fork_choice);
 
@@ -662,7 +655,6 @@ where
             .genesis_state_root
             .ok_or("Cannot build without a genesis state root")?;
         let validator_monitor_config = self.validator_monitor_config.unwrap_or_default();
-        let head_tracker = Arc::new(self.head_tracker.unwrap_or_default());
 
         let beacon_proposer_cache: Arc<Mutex<BeaconProposerCache>> = <_>::default();
         let mut validator_monitor = ValidatorMonitor::new(
@@ -716,8 +708,6 @@ where
                         &log,
                     )?;
 
-                    // Update head tracker.
-                    head_tracker.register_block(block_root, block.parent_root(), block.slot());
                     (block_root, block, true)
                 }
                 Err(e) => return Err(descriptive_db_error("head block", &e)),
@@ -805,11 +795,6 @@ where
         //
         // This *must* be stored before constructing the `BeaconChain`, so that its `Drop` instance
         // doesn't write a `PersistedBeaconChain` without the rest of the batch.
-        self.pending_io_batch.push(BeaconChain::<
-            Witness<TSlotClock, TEth1Backend, TEthSpec, THotStore, TColdStore>,
-        >::persist_head_in_batch_standalone(
-            genesis_block_root, &head_tracker
-        ));
         self.pending_io_batch.push(BeaconChain::<
             Witness<TSlotClock, TEth1Backend, TEthSpec, THotStore, TColdStore>,
         >::persist_fork_choice_in_batch_standalone(
@@ -897,7 +882,6 @@ where
             fork_choice_signal_tx,
             fork_choice_signal_rx,
             event_handler: self.event_handler,
-            head_tracker,
             snapshot_cache: TimeoutRwLock::new(SnapshotCache::new(
                 DEFAULT_SNAPSHOT_CACHE_SIZE,
                 head_for_snapshot_cache,

beacon_node/beacon_chain/src/canonical_head.rs

@@ -1062,7 +1062,8 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
         self.store_migrator.process_finalization(
             new_finalized_state_root.into(),
             new_view.finalized_checkpoint,
-            self.head_tracker.clone(),
+            todo!(),
+            // self.head_tracker.clone(),
         )?;
 
         // Prune blobs in the background.