Only cache check point state if it hasn't existed in other cache (#7037)

* Only cache epoch boundary state in the event of skipped epoch boundary slot

* checkpoint

* remove lods

* checkppoint again

* Cache: fill if empty

* Don't include the sync fixes

* Update sync utils

* Avoid extra process slots

Co-authored-by: nisdas <nishdas93@gmail.com>

Author: terencechain

beacon-chain/blockchain/process_attestation_helpers.go

@@ -20,6 +20,7 @@ import (
 func (s *Service) getAttPreState(ctx context.Context, c *ethpb.Checkpoint) (*stateTrie.BeaconState, error) {
 	s.checkpointStateLock.Lock()
 	defer s.checkpointStateLock.Unlock()
+
 	cachedState, err := s.checkpointState.StateByCheckpoint(c)
 	if err != nil {
 		return nil, errors.Wrap(err, "could not get cached checkpoint state")
@@ -39,12 +40,21 @@ func (s *Service) getAttPreState(ctx context.Context, c *ethpb.Checkpoint) (*sta
 		if err != nil {
 			return nil, errors.Wrapf(err, "could not process slots up to %d", helpers.StartSlot(c.Epoch))
 		}
+		if err := s.checkpointState.AddCheckpointState(c, baseState); err != nil {
+			return nil, errors.Wrap(err, "could not saved checkpoint state to cache")
+		}
+		return baseState, nil
 	}
 
-	if err := s.checkpointState.AddCheckpointState(c, baseState); err != nil {
-		return nil, errors.Wrap(err, "could not saved checkpoint state to cache")
+	has, err := s.stateGen.HasState(ctx, bytesutil.ToBytes32(c.Root))
+	if err != nil {
+		return nil, err
+	}
+	if !has {
+		if err := s.checkpointState.AddCheckpointState(c, baseState); err != nil {
+			return nil, errors.Wrap(err, "could not saved checkpoint state to cache")
+		}
 	}
-
 	return baseState, nil
 
 }

beacon-chain/blockchain/process_block_helpers.go

@@ -78,7 +78,11 @@ func (s *Service) verifyBlkPreState(ctx context.Context, b *ethpb.BeaconBlock) e
 	if !s.stateGen.StateSummaryExists(ctx, parentRoot) && !s.beaconDB.HasBlock(ctx, parentRoot) {
 		return errors.New("could not reconstruct parent state")
 	}
-	if !s.stateGen.HasState(ctx, parentRoot) {
+	has, err := s.stateGen.HasState(ctx, parentRoot)
+	if err != nil {
+		return err
+	}
+	if !has {
 		if err := s.beaconDB.SaveBlocks(ctx, s.getInitSyncBlocks()); err != nil {
 			return errors.Wrap(err, "could not save initial sync blocks")
 		}

beacon-chain/state/stategen/hot.go

@@ -14,12 +14,18 @@ import (
 )
 
 // HasState returns true if the state exists in cache or in DB.
-func (s *State) HasState(ctx context.Context, blockRoot [32]byte) bool {
+func (s *State) HasState(ctx context.Context, blockRoot [32]byte) (bool, error) {
 	if s.hotStateCache.Has(blockRoot) {
-		return true
+		return true, nil
 	}
-
-	return s.beaconDB.HasState(ctx, blockRoot)
+	_, has, err := s.epochBoundaryStateCache.getByRoot(blockRoot)
+	if err != nil {
+		return false, err
+	}
+	if has {
+		return true, nil
+	}
+	return s.beaconDB.HasState(ctx, blockRoot), nil
 }
 
 // SaveStateSummary saves the relevant state summary for a block and its corresponding state slot in the