Avoid repeated state creation in validator reading

core/blockchain.go

@@ -2280,18 +2280,29 @@ func (bc *BlockChain) ReadTxLookupEntry(txID common.Hash) (common.Hash, uint64,
 	return rawdb.ReadTxLookupEntry(bc.db, txID)
 }
 
-// ReadValidatorInformationAt reads staking
+// ReadValidatorInformationAtRoot reads staking
 // information of given validatorWrapper at a specific state root
-func (bc *BlockChain) ReadValidatorInformationAt(
+func (bc *BlockChain) ReadValidatorInformationAtRoot(
 	addr common.Address, root common.Hash,
 ) (*staking.ValidatorWrapper, error) {
 	state, err := bc.StateAt(root)
 	if err != nil || state == nil {
 		return nil, errors.Wrapf(err, "at root: %s", root.Hex())
 	}
+	return bc.ReadValidatorInformationAtState(addr, state)
+}
+
+// ReadValidatorInformationAtState reads staking
+// information of given validatorWrapper at a specific state root
+func (bc *BlockChain) ReadValidatorInformationAtState(
+	addr common.Address, state *state.DB,
+) (*staking.ValidatorWrapper, error) {
+	if state == nil {
+		return nil, errors.New("empty state")
+	}
 	wrapper, err := state.ValidatorWrapper(addr)
 	if err != nil {
-		return nil, errors.Wrapf(err, "at root: %s", root.Hex())
+		return nil, err
 	}
 	return wrapper, nil
 }
@@ -2300,7 +2311,7 @@ func (bc *BlockChain) ReadValidatorInformationAt(
 func (bc *BlockChain) ReadValidatorInformation(
 	addr common.Address,
 ) (*staking.ValidatorWrapper, error) {
-	return bc.ReadValidatorInformationAt(addr, bc.CurrentBlock().Root())
+	return bc.ReadValidatorInformationAtRoot(addr, bc.CurrentBlock().Root())
 }
 
 // ReadValidatorSnapshotAtEpoch reads the snapshot

core/chain_makers.go

@@ -273,6 +273,14 @@ func (cr *fakeChainReader) ReadValidatorInformation(
 ) (*staking.ValidatorWrapper, error) {
 	return nil, nil
 }
+func (cr *fakeChainReader) ReadValidatorInformationAtState(
+	addr common.Address, state *state.DB,
+) (*staking.ValidatorWrapper, error) {
+	return nil, nil
+}
+func (cr *fakeChainReader) StateAt(root common.Hash) (*state.DB, error) {
+	return nil, nil
+}
 func (cr *fakeChainReader) ReadValidatorSnapshot(
 	addr common.Address,
 ) (*staking.ValidatorSnapshot, error) {

hmy/staking.go

@@ -282,7 +282,7 @@ func (hmy *Harmony) GetValidatorInformation(
 	addr common.Address, block *types.Block,
 ) (*staking.ValidatorRPCEnhanced, error) {
 	bc := hmy.BlockChain
-	wrapper, err := bc.ReadValidatorInformationAt(addr, block.Root())
+	wrapper, err := bc.ReadValidatorInformationAtRoot(addr, block.Root())
 	if err != nil {
 		s, _ := internalCommon.AddressToBech32(addr)
 		return nil, errors.Wrapf(err, "not found address in current state %s", s)
@@ -469,7 +469,7 @@ func (hmy *Harmony) GetDelegationsByValidator(validator common.Address) []*staki
 func (hmy *Harmony) GetDelegationsByValidatorAtBlock(
 	validator common.Address, block *types.Block,
 ) []*staking.Delegation {
-	wrapper, err := hmy.BlockChain.ReadValidatorInformationAt(validator, block.Root())
+	wrapper, err := hmy.BlockChain.ReadValidatorInformationAtRoot(validator, block.Root())
 	if err != nil || wrapper == nil {
 		return nil
 	}
@@ -501,7 +501,7 @@ func (hmy *Harmony) GetDelegationsByDelegatorByBlock(
 	}
 
 	for i := range delegationIndexes {
-		wrapper, err := hmy.BlockChain.ReadValidatorInformationAt(
+		wrapper, err := hmy.BlockChain.ReadValidatorInformationAtRoot(
 			delegationIndexes[i].ValidatorAddress, block.Root(),
 		)
 		if err != nil || wrapper == nil {
@@ -548,7 +548,7 @@ func (hmy *Harmony) GetUndelegationPayouts(
 
 	lockingPeriod := hmy.GetDelegationLockingPeriodInEpoch(undelegationPayoutBlock.Epoch())
 	for _, validator := range hmy.GetAllValidatorAddresses() {
-		wrapper, err := hmy.BlockChain.ReadValidatorInformationAt(validator, undelegationPayoutBlock.Root())
+		wrapper, err := hmy.BlockChain.ReadValidatorInformationAtRoot(validator, undelegationPayoutBlock.Root())
 		if err != nil || wrapper == nil {
 			continue // Not a validator at this epoch or unable to fetch validator info because of pruned state.
 		}

internal/chain/engine.go

@@ -245,6 +245,8 @@ func payoutUndelegations(
 		return errors.New(msg)
 	}
 	// Payout undelegated/unlocked tokens
+	lockPeriod := GetLockPeriodInEpoch(chain, header.Epoch())
+	noEarlyUnlock := chain.Config().IsNoEarlyUnlock(header.Epoch())
 	for _, validator := range validators {
 		wrapper, err := state.ValidatorWrapper(validator)
 		if err != nil {
@@ -252,14 +254,14 @@ func payoutUndelegations(
 				"[Finalize] failed to get validator from state to finalize",
 			)
 		}
-		lockPeriod := GetLockPeriodInEpoch(chain, header.Epoch())
-		noEarlyUnlock := chain.Config().IsNoEarlyUnlock(header.Epoch())
 		for i := range wrapper.Delegations {
 			delegation := &wrapper.Delegations[i]
 			totalWithdraw := delegation.RemoveUnlockedUndelegations(
 				header.Epoch(), wrapper.LastEpochInCommittee, lockPeriod, noEarlyUnlock,
 			)
-			state.AddBalance(delegation.DelegatorAddress, totalWithdraw)
+			if totalWithdraw.Sign() != 0 {
+				state.AddBalance(delegation.DelegatorAddress, totalWithdraw)
+			}
 		}
 		countTrack[validator] = len(wrapper.Delegations)
 	}

shard/committee/assignment.go

@@ -4,6 +4,8 @@ import (
 	"encoding/json"
 	"math/big"
 
+	"github.com/harmony-one/harmony/core/state"
+
 	"github.com/harmony-one/harmony/crypto/bls"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -38,7 +40,11 @@ type Reader interface {
 // StakingCandidatesReader ..
 type StakingCandidatesReader interface {
 	CurrentBlock() *types.Block
+	StateAt(root common.Hash) (*state.DB, error)
 	ReadValidatorInformation(addr common.Address) (*staking.ValidatorWrapper, error)
+	ReadValidatorInformationAtState(
+		addr common.Address, state *state.DB,
+	) (*staking.ValidatorWrapper, error)
 	ReadValidatorSnapshot(addr common.Address) (*staking.ValidatorSnapshot, error)
 	ValidatorCandidates() []common.Address
 }
@@ -145,11 +151,15 @@ func prepareOrders(
 		blsKeys[pubKey] = struct{}{}
 	}
 
+	state, err := stakedReader.StateAt(stakedReader.CurrentBlock().Root())
+	if err != nil || state == nil {
+		return nil, errors.Wrapf(err, "not state found at root: %s", stakedReader.CurrentBlock().Root().Hex())
+	}
 	for i := range candidates {
 		// TODO: reading validator wrapper from DB could be a bottle net when there are hundreds of validators
 		// with thousands of delegator data.
-		validator, err := stakedReader.ReadValidatorInformation(
+		validator, err := stakedReader.ReadValidatorInformationAtState(
-			candidates[i],
+			candidates[i], state,
 		)
 		if err != nil {
 			return nil, err