diff --git a/api/service/explorer/service.go b/api/service/explorer/service.go
index dce59d85b..17e5a0476 100644
--- a/api/service/explorer/service.go
+++ b/api/service/explorer/service.go
@@ -282,8 +282,8 @@ func (s *Service) GetExplorerBlocks(w http.ResponseWriter, r *http.Request) {
 			curEpoch = int64(block.Epoch)
 		}
 		if withSigners {
-			pubkeys := make([]*bls.PublicKey, len(committee.NodeList))
-			for i, validator := range committee.NodeList {
+			pubkeys := make([]*bls.PublicKey, len(committee.Slots))
+			for i, validator := range committee.Slots {
 				pubkeys[i] = new(bls.PublicKey)
 				validator.BlsPublicKey.ToLibBLSPublicKey(pubkeys[i])
 			}
@@ -291,7 +291,7 @@ func (s *Service) GetExplorerBlocks(w http.ResponseWriter, r *http.Request) {
 			if err == nil && accountBlocks[id+1] != nil {
 				err = mask.SetMask(accountBlocks[id+1].Header().LastCommitBitmap())
 				if err == nil {
-					for _, validator := range committee.NodeList {
+					for _, validator := range committee.Slots {
 						oneAddress, err := common2.AddressToBech32(validator.EcdsaAddress)
 						if err != nil {
 							continue
@@ -403,8 +403,8 @@ func (s *ServiceAPI) GetExplorerBlocks(ctx context.Context, from, to, page, offs
 			curEpoch = int64(block.Epoch)
 		}
 		if withSigners {
-			pubkeys := make([]*bls.PublicKey, len(committee.NodeList))
-			for i, validator := range committee.NodeList {
+			pubkeys := make([]*bls.PublicKey, len(committee.Slots))
+			for i, validator := range committee.Slots {
 				pubkeys[i] = new(bls.PublicKey)
 				validator.BlsPublicKey.ToLibBLSPublicKey(pubkeys[i])
 			}
@@ -412,7 +412,7 @@ func (s *ServiceAPI) GetExplorerBlocks(ctx context.Context, from, to, page, offs
 			if err == nil && accountBlocks[id+1] != nil {
 				err = mask.SetMask(accountBlocks[id+1].Header().LastCommitBitmap())
 				if err == nil {
-					for _, validator := range committee.NodeList {
+					for _, validator := range committee.Slots {
 						oneAddress, err := common2.AddressToBech32(validator.EcdsaAddress)
 						if err != nil {
 							continue
@@ -592,7 +592,7 @@ func (s *Service) GetExplorerCommittee(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	validators := &Committee{}
-	for _, validator := range committee.NodeList {
+	for _, validator := range committee.Slots {
 		validatorBalance := big.NewInt(0)
 		validatorBalance, err := s.GetAccountBalance(validator.EcdsaAddress)
 		if err != nil {
@@ -645,7 +645,7 @@ func (s *ServiceAPI) GetExplorerCommittee(ctx context.Context, shardID uint32, e
 		return nil, err
 	}
 	validators := &Committee{}
-	for _, validator := range committee.NodeList {
+	for _, validator := range committee.Slots {
 		validatorBalance := big.NewInt(0)
 		validatorBalance, err := s.Service.GetAccountBalance(validator.EcdsaAddress)
 		if err != nil {
diff --git a/api/service/explorer/storage_test.go b/api/service/explorer/storage_test.go
index ea3832507..bd08e4c9a 100644
--- a/api/service/explorer/storage_test.go
+++ b/api/service/explorer/storage_test.go
@@ -90,10 +90,10 @@ func TestDumpCommittee(t *testing.T) {
 	BlsPublicKey2 := new(shard.BlsPublicKey)
 	BlsPublicKey1.FromLibBLSPublicKey(blsPubKey1)
 	BlsPublicKey2.FromLibBLSPublicKey(blsPubKey2)
-	nodeID1 := shard.NodeID{EcdsaAddress: common.HexToAddress("52789f18a342da8023cc401e5d2b14a6b710fba9"), BlsPublicKey: *BlsPublicKey1}
-	nodeID2 := shard.NodeID{EcdsaAddress: common.HexToAddress("7c41e0668b551f4f902cfaec05b5bdca68b124ce"), BlsPublicKey: *BlsPublicKey2}
-	nodeIDList := []shard.NodeID{nodeID1, nodeID2}
-	committee := shard.Committee{ShardID: uint32(0), NodeList: nodeIDList}
+	nodeID1 := shard.Slot{EcdsaAddress: common.HexToAddress("52789f18a342da8023cc401e5d2b14a6b710fba9"), BlsPublicKey: *BlsPublicKey1}
+	nodeID2 := shard.Slot{EcdsaAddress: common.HexToAddress("7c41e0668b551f4f902cfaec05b5bdca68b124ce"), BlsPublicKey: *BlsPublicKey2}
+	nodeIDList := []shard.Slot{nodeID1, nodeID2}
+	committee := shard.Committee{ShardID: uint32(0), Slots: nodeIDList}
 	shardID := uint32(0)
 	epoch := uint64(0)
 	ins := GetStorageInstance("1.1.1.1", "3333", true)
diff --git a/consensus/consensus_service.go b/consensus/consensus_service.go
index 278e4aea8..eda4e804e 100644
--- a/consensus/consensus_service.go
+++ b/consensus/consensus_service.go
@@ -428,7 +428,7 @@ func (consensus *Consensus) getLeaderPubKeyFromCoinbase(header *block.Header) (*
 		)
 	}
 	committerKey := new(bls.PublicKey)
-	for _, member := range committee.NodeList {
+	for _, member := range committee.Slots {
 		if member.EcdsaAddress == header.Coinbase() {
 			err := member.BlsPublicKey.ToLibBLSPublicKey(committerKey)
 			if err != nil {
diff --git a/consensus/engine/consensus_engine.go b/consensus/engine/consensus_engine.go
index 980b160c6..a2a9ad8b5 100644
--- a/consensus/engine/consensus_engine.go
+++ b/consensus/engine/consensus_engine.go
@@ -40,8 +40,8 @@ type ChainReader interface {
 	// Thus, only should be used to read the shard state of the current chain.
 	ReadShardState(epoch *big.Int) (shard.State, error)
 
-	// CurrentValidatorAddresses retrieves the current list of validators
-	CurrentValidatorAddresses() []common.Address
+	// ActiveValidatorAddresses retrieves the list of active validators
+	ActiveValidatorAddresses() []common.Address
 }
 
 // Engine is an algorithm agnostic consensus engine.
diff --git a/core/blockchain.go b/core/blockchain.go
index ed12c4d62..e0e608581 100644
--- a/core/blockchain.go
+++ b/core/blockchain.go
@@ -70,9 +70,9 @@ const (
 	commitsCacheLimit                  = 10
 	epochCacheLimit                    = 10
 	randomnessCacheLimit               = 10
-	stakingCacheLimit                  = 256
-	validatorListCacheLimit            = 2
-	validatorListByDelegatorCacheLimit = 256
+	validatorCacheLimit                = 1024
+	validatorListCacheLimit            = 10
+	validatorListByDelegatorCacheLimit = 1024
 
 	// BlockChainVersion ensures that an incompatible database forces a resync from scratch.
 	BlockChainVersion = 3
@@ -135,7 +135,7 @@ type BlockChain struct {
 	lastCommitsCache              *lru.Cache
 	epochCache                    *lru.Cache // Cache epoch number → first block number
 	randomnessCache               *lru.Cache // Cache for vrf/vdf
-	stakingCache                  *lru.Cache // Cache for staking validator
+	validatorCache                *lru.Cache // Cache for staking validator
 	validatorListCache            *lru.Cache // Cache of validator list
 	validatorListByDelegatorCache *lru.Cache // Cache of validator list by delegator
 
@@ -174,7 +174,7 @@ func NewBlockChain(db ethdb.Database, cacheConfig *CacheConfig, chainConfig *par
 	commitsCache, _ := lru.New(commitsCacheLimit)
 	epochCache, _ := lru.New(epochCacheLimit)
 	randomnessCache, _ := lru.New(randomnessCacheLimit)
-	stakingCache, _ := lru.New(stakingCacheLimit)
+	stakingCache, _ := lru.New(validatorCacheLimit)
 	validatorListCache, _ := lru.New(validatorListCacheLimit)
 	validatorListByDelegatorCache, _ := lru.New(validatorListByDelegatorCacheLimit)
 
@@ -195,7 +195,7 @@ func NewBlockChain(db ethdb.Database, cacheConfig *CacheConfig, chainConfig *par
 		lastCommitsCache:              commitsCache,
 		epochCache:                    epochCache,
 		randomnessCache:               randomnessCache,
-		stakingCache:                  stakingCache,
+		validatorCache:                stakingCache,
 		validatorListCache:            validatorListCache,
 		validatorListByDelegatorCache: validatorListByDelegatorCache,
 		engine:                        engine,
@@ -1078,6 +1078,7 @@ func (bc *BlockChain) WriteBlockWithState(block *types.Block, receipts []*types.
 	batch := bc.db.NewBatch()
 	rawdb.WriteReceipts(batch, block.Hash(), block.NumberU64(), receipts)
 
+	//// Cross-shard txns
 	epoch := block.Header().Epoch()
 	if bc.chainConfig.IsCrossTx(block.Epoch()) {
 		shardingConfig := shard.Schedule.InstanceForEpoch(epoch)
@@ -1097,6 +1098,7 @@ func (bc *BlockChain) WriteBlockWithState(block *types.Block, receipts []*types.
 		bc.WriteCXReceiptsProofSpent(block.IncomingReceipts())
 	}
 
+	//// VRF + VDF
 	//check non zero VRF field in header and add to local db
 	if len(block.Vrf()) > 0 {
 		vrfBlockNumbers, _ := bc.ReadEpochVrfBlockNums(block.Header().Epoch())
@@ -1130,16 +1132,50 @@ func (bc *BlockChain) WriteBlockWithState(block *types.Block, receipts []*types.
 		}
 	}
 
+	//// Shard State and Validator Update
 	header := block.Header()
 	if header.ShardStateHash() != (common.Hash{}) {
+		// Write shard state for the new epoch
 		epoch := new(big.Int).Add(header.Epoch(), common.Big1)
-		err = bc.WriteShardStateBytes(batch, epoch, header.ShardState())
+		shardState, err := bc.WriteShardStateBytes(batch, epoch, header.ShardState())
 		if err != nil {
 			header.Logger(utils.Logger()).Warn().Err(err).Msg("cannot store shard state")
 			return NonStatTy, err
 		}
+
+		// Find all the active validator addresses and do a snapshot
+		allActiveValidators := []common.Address{}
+		processed := make(map[common.Address]struct{})
+		for i := range *shardState {
+			shard := (*shardState)[i]
+			for j := range shard.Slots {
+				slot := shard.Slots[j]
+				if slot.StakeWithDelegationApplied != nil { // For external validator
+					_, ok := processed[slot.EcdsaAddress]
+					if !ok {
+						processed[slot.EcdsaAddress] = struct{}{}
+						allActiveValidators = append(allActiveValidators, shard.Slots[j].EcdsaAddress)
+					}
+				}
+			}
+		}
+		bc.UpdateActiveValidatorsSnapshot(allActiveValidators)
 	}
 
+	// Do bookkeeping for new staking txns
+	if bc.chainConfig.IsStaking(block.Epoch()) {
+		for _, tx := range block.StakingTransactions() {
+			err = bc.UpdateStakingMetaData(tx)
+			// keep offchain database consistency with onchain we need revert
+			// but it should not happend unless local database corrupted
+			if err != nil {
+				utils.Logger().Debug().Msgf("oops, UpdateStakingMetaData failed, err: %+v", err)
+				return NonStatTy, err
+			}
+		}
+	}
+
+	//// Cross-links
 	if len(header.CrossLinks()) > 0 {
 		crossLinks := &types.CrossLinks{}
 		err = rlp.DecodeBytes(header.CrossLinks(), crossLinks)
@@ -1159,19 +1195,6 @@ func (bc *BlockChain) WriteBlockWithState(block *types.Block, receipts []*types.
 			bc.WriteShardLastCrossLink(crossLink.ShardID(), crossLink)
 		}
 	}
-
-	if bc.chainConfig.IsStaking(block.Epoch()) {
-		for _, tx := range block.StakingTransactions() {
-			err = bc.UpdateStakingMetaData(tx)
-			// keep offchain database consistency with onchain we need revert
-			// but it should not happend unless local database corrupted
-			if err != nil {
-				utils.Logger().Debug().Msgf("oops, UpdateStakingMetaData failed, err: %+v", err)
-				return NonStatTy, err
-			}
-		}
-	}
-
 	/////////////////////////// END
 
 	// If the total difficulty is higher than our known, add it to the canonical chain
@@ -1870,18 +1893,18 @@ func (bc *BlockChain) WriteShardState(
 // WriteShardStateBytes saves the given sharding state under the given epoch number.
 func (bc *BlockChain) WriteShardStateBytes(db rawdb.DatabaseWriter,
 	epoch *big.Int, shardState []byte,
-) error {
+) (*shard.State, error) {
 	decodeShardState := shard.State{}
 	if err := rlp.DecodeBytes(shardState, &decodeShardState); err != nil {
-		return err
+		return nil, err
 	}
 	err := rawdb.WriteShardStateBytes(db, epoch, shardState)
 	if err != nil {
-		return err
+		return nil, err
 	}
 	cacheKey := string(epoch.Bytes())
 	bc.shardStateCache.Add(cacheKey, decodeShardState)
-	return nil
+	return &decodeShardState, nil
 }
 
 // ReadLastCommits retrieves last commits.
@@ -2276,9 +2299,9 @@ func (bc *BlockChain) ReadTxLookupEntry(txID common.Hash) (common.Hash, uint64,
 	return rawdb.ReadTxLookupEntry(bc.db, txID)
 }
 
-// ReadStakingValidator reads staking information of given validatorWrapper
-func (bc *BlockChain) ReadStakingValidator(addr common.Address) (*staking.ValidatorWrapper, error) {
-	if cached, ok := bc.stakingCache.Get("staking-" + string(addr.Bytes())); ok {
+// ReadValidatorData reads staking information of given validatorWrapper
+func (bc *BlockChain) ReadValidatorData(addr common.Address) (*staking.ValidatorWrapper, error) {
+	if cached, ok := bc.validatorCache.Get("validator-" + string(addr.Bytes())); ok {
 		by := cached.([]byte)
 		v := staking.ValidatorWrapper{}
 		if err := rlp.DecodeBytes(by, &v); err != nil {
@@ -2287,12 +2310,12 @@ func (bc *BlockChain) ReadStakingValidator(addr common.Address) (*staking.Valida
 		return &v, nil
 	}
 
-	return rawdb.ReadStakingValidator(bc.db, addr)
+	return rawdb.ReadValidatorData(bc.db, addr)
 }
 
-// WriteStakingValidator reads staking information of given validatorWrapper
-func (bc *BlockChain) WriteStakingValidator(v *staking.ValidatorWrapper) error {
-	err := rawdb.WriteStakingValidator(bc.db, v)
+// WriteValidatorData writes staking information of given validatorWrapper
+func (bc *BlockChain) WriteValidatorData(v *staking.ValidatorWrapper) error {
+	err := rawdb.WriteValidatorData(bc.db, v)
 	if err != nil {
 		return err
 	}
@@ -2300,7 +2323,89 @@ func (bc *BlockChain) WriteStakingValidator(v *staking.ValidatorWrapper) error {
 	if err != nil {
 		return err
 	}
-	bc.stakingCache.Add("staking-"+string(v.Address.Bytes()), by)
+	bc.validatorCache.Add("validator-"+string(v.Address.Bytes()), by)
+	return nil
+}
+
+// ReadValidatorSnapshot reads the snapshot staking information of given validator address
+// TODO: put epoch number in to snapshot too.
+func (bc *BlockChain) ReadValidatorSnapshot(addr common.Address) (*staking.ValidatorWrapper, error) {
+	if cached, ok := bc.validatorCache.Get("validator-snapshot-" + string(addr.Bytes())); ok {
+		by := cached.([]byte)
+		v := staking.ValidatorWrapper{}
+		if err := rlp.DecodeBytes(by, &v); err != nil {
+			return nil, err
+		}
+		return &v, nil
+	}
+
+	return rawdb.ReadValidatorSnapshot(bc.db, addr)
+}
+
+// WriteValidatorSnapshots writes the snapshot of provided list of validators
+func (bc *BlockChain) WriteValidatorSnapshots(addrs []common.Address) error {
+	// Read all validator's current data
+	validators := []*staking.ValidatorWrapper{}
+	for _, addr := range addrs {
+		validator, err := bc.ReadValidatorData(addr)
+		if err != nil {
+			return err
+		}
+		validators = append(validators, validator)
+	}
+
+	// Batch write the current data as snapshot
+	batch := bc.db.NewBatch()
+	for i := range validators {
+		err := rawdb.WriteValidatorSnapshot(batch, validators[i])
+		if err != nil {
+			return err
+		}
+	}
+	if err := batch.Write(); err != nil {
+		return err
+	}
+
+	// Update cache
+	for i := range validators {
+		by, err := rlp.EncodeToBytes(validators[i])
+		if err == nil {
+			bc.validatorCache.Add("validator-snapshot-"+string(validators[i].Address.Bytes()), by)
+		}
+	}
+	return nil
+}
+
+// DeleteValidatorSnapshots deletes the snapshot staking information of given validator address
+func (bc *BlockChain) DeleteValidatorSnapshots(addrs []common.Address) error {
+	batch := bc.db.NewBatch()
+	for i := range addrs {
+		rawdb.DeleteValidatorSnapshot(batch, addrs[i])
+	}
+	if err := batch.Write(); err != nil {
+		return err
+	}
+	for i := range addrs {
+		bc.validatorCache.Remove("validator-snapshot-" + string(addrs[i].Bytes()))
+	}
+	return nil
+}
+
+// UpdateActiveValidatorsSnapshot updates the list of active validators and updates the content snapshot of the active validators
+func (bc *BlockChain) UpdateActiveValidatorsSnapshot(activeValidators []common.Address) error {
+	prevActiveValidators, err := bc.ReadActiveValidatorList()
+	if err != nil {
+		return err
+	}
+
+	err = bc.DeleteValidatorSnapshots(prevActiveValidators)
+	if err != nil {
+		return err
+	}
+
+	if err = bc.WriteValidatorSnapshots(activeValidators); err != nil {
+		return err
+	}
 	return nil
 }
 
@@ -2314,12 +2419,12 @@ func (bc *BlockChain) ReadValidatorList() ([]common.Address, error) {
 		}
 		return m, nil
 	}
-	return rawdb.ReadValidatorList(bc.db)
+	return rawdb.ReadValidatorList(bc.db, false)
 }
 
 // WriteValidatorList writes the list of validator addresses to database
 func (bc *BlockChain) WriteValidatorList(addrs []common.Address) error {
-	err := rawdb.WriteValidatorList(bc.db, addrs)
+	err := rawdb.WriteValidatorList(bc.db, addrs, false)
 	if err != nil {
 		return err
 	}
@@ -2330,6 +2435,32 @@ func (bc *BlockChain) WriteValidatorList(addrs []common.Address) error {
 	return nil
 }
 
+// ReadActiveValidatorList reads the addresses of active validators
+func (bc *BlockChain) ReadActiveValidatorList() ([]common.Address, error) {
+	if cached, ok := bc.validatorListCache.Get("activeValidatorList"); ok {
+		by := cached.([]byte)
+		m := []common.Address{}
+		if err := rlp.DecodeBytes(by, &m); err != nil {
+			return nil, err
+		}
+		return m, nil
+	}
+	return rawdb.ReadValidatorList(bc.db, true)
+}
+
+// WriteActiveValidatorList writes the list of active validator addresses to database
+func (bc *BlockChain) WriteActiveValidatorList(addrs []common.Address) error {
+	err := rawdb.WriteValidatorList(bc.db, addrs, true)
+	if err != nil {
+		return err
+	}
+	bytes, err := rlp.EncodeToBytes(addrs)
+	if err == nil {
+		bc.validatorListCache.Add("activeValidatorList", bytes)
+	}
+	return nil
+}
+
 // ReadValidatorListByDelegator reads the addresses of validators delegated by a delegator
 func (bc *BlockChain) ReadValidatorListByDelegator(delegator common.Address) ([]common.Address, error) {
 	if cached, ok := bc.validatorListByDelegatorCache.Get(delegator.Bytes()); ok {
@@ -2413,8 +2544,9 @@ func (bc *BlockChain) UpdateStakingMetaData(tx *staking.StakingTransaction) erro
 	return nil
 }
 
-// CurrentValidatorAddresses returns the address of active validators for current epoch
-func (bc *BlockChain) CurrentValidatorAddresses() []common.Address {
+// ActiveValidatorAddresses returns the address of active validators for current epoch
+// TODO: should only return those that are selected by epos.
+func (bc *BlockChain) ActiveValidatorAddresses() []common.Address {
 	list, err := bc.ReadValidatorList()
 	if err != nil {
 		return make([]common.Address, 0)
@@ -2428,6 +2560,7 @@ func (bc *BlockChain) CurrentValidatorAddresses() []common.Address {
 		if err != nil {
 			continue
 		}
+		// TODO: double check this logic here.
 		epoch := shard.Schedule.CalcEpochNumber(val.CreationHeight.Uint64())
 		if epoch.Cmp(currentEpoch) >= 0 {
 			// wait for next epoch
diff --git a/core/chain_makers.go b/core/chain_makers.go
index f09bc8028..51f501421 100644
--- a/core/chain_makers.go
+++ b/core/chain_makers.go
@@ -270,4 +270,4 @@ func (cr *fakeChainReader) GetHeaderByHash(hash common.Hash) *block.Header
 func (cr *fakeChainReader) GetHeader(hash common.Hash, number uint64) *block.Header { return nil }
 func (cr *fakeChainReader) GetBlock(hash common.Hash, number uint64) *types.Block   { return nil }
 func (cr *fakeChainReader) ReadShardState(epoch *big.Int) (shard.State, error)      { return nil, nil }
-func (cr *fakeChainReader) CurrentValidatorAddresses() []common.Address             { return nil }
+func (cr *fakeChainReader) ActiveValidatorAddresses() []common.Address              { return nil }
diff --git a/core/rawdb/accessors_chain.go b/core/rawdb/accessors_chain.go
index 97324d79c..315cc8670 100644
--- a/core/rawdb/accessors_chain.go
+++ b/core/rawdb/accessors_chain.go
@@ -542,7 +542,7 @@ func WriteShardLastCrossLink(db DatabaseWriter, shardID uint32, data []byte) err
 // ReadCXReceipts retrieves all the transactions of receipts given destination shardID, number and blockHash
 func ReadCXReceipts(db DatabaseReader, shardID uint32, number uint64, hash common.Hash, temp bool) (types.CXReceipts, error) {
 	data, err := db.Get(cxReceiptKey(shardID, number, hash, temp))
-	if len(data) == 0 || err != nil {
+	if err != nil || len(data) == 0 {
 		utils.Logger().Info().Err(err).Uint64("number", number).Int("dataLen", len(data)).Msg("ReadCXReceipts")
 		return nil, err
 	}
@@ -614,11 +614,40 @@ func WriteCXReceiptsProofUnspentCheckpoint(db DatabaseWriter, shardID uint32, bl
 	return db.Put(cxReceiptUnspentCheckpointKey(shardID), by)
 }
 
-// ReadStakingValidator retrieves staking validator by its address
-func ReadStakingValidator(db DatabaseReader, addr common.Address) (*staking.ValidatorWrapper, error) {
-	data, err := db.Get(stakingKey(addr))
-	if len(data) == 0 || err != nil {
-		utils.Logger().Info().Err(err).Msg("ReadStakingValidator")
+// ReadValidatorData retrieves staking validator by its address
+func ReadValidatorData(db DatabaseReader, addr common.Address) (*staking.ValidatorWrapper, error) {
+	data, err := db.Get(validatorKey(addr))
+	if err != nil || len(data) == 0 {
+		utils.Logger().Info().Err(err).Msg("ReadValidatorData")
+		return nil, err
+	}
+	v := staking.ValidatorWrapper{}
+	if err := rlp.DecodeBytes(data, &v); err != nil {
+		utils.Logger().Error().Err(err).Str("address", addr.Hex()).Msg("Unable to Decode staking validator from database")
+		return nil, err
+	}
+	return &v, nil
+}
+
+// WriteValidatorData stores validator's information by its address
+func WriteValidatorData(db DatabaseWriter, v *staking.ValidatorWrapper) error {
+	bytes, err := rlp.EncodeToBytes(v)
+	if err != nil {
+		utils.Logger().Error().Msg("[WriteValidatorData] Failed to encode")
+		return err
+	}
+	if err := db.Put(validatorKey(v.Address), bytes); err != nil {
+		utils.Logger().Error().Msg("[WriteValidatorData] Failed to store to database")
+		return err
+	}
+	return err
+}
+
+// ReadValidatorSnapshot retrieves validator's snapshot by its address
+func ReadValidatorSnapshot(db DatabaseReader, addr common.Address) (*staking.ValidatorWrapper, error) {
+	data, err := db.Get(validatorSnapshotKey(addr))
+	if err != nil || len(data) == 0 {
+		utils.Logger().Info().Err(err).Msg("ReadValidatorSnapshot")
 		return nil, err
 	}
 	v := staking.ValidatorWrapper{}
@@ -629,22 +658,36 @@ func ReadStakingValidator(db DatabaseReader, addr common.Address) (*staking.Vali
 	return &v, nil
 }
 
-// WriteStakingValidator stores staking validator's information by its address
-func WriteStakingValidator(db DatabaseWriter, v *staking.ValidatorWrapper) error {
+// WriteValidatorSnapshot stores validator's snapshot by its address
+func WriteValidatorSnapshot(db DatabaseWriter, v *staking.ValidatorWrapper) error {
 	bytes, err := rlp.EncodeToBytes(v)
 	if err != nil {
-		utils.Logger().Error().Msg("[WriteStakingValidator] Failed to encode")
+		utils.Logger().Error().Msg("[WriteValidatorSnapshot] Failed to encode")
+		return err
 	}
-	if err := db.Put(stakingKey(v.Address), bytes); err != nil {
-		utils.Logger().Error().Msg("[WriteStakingValidator] Failed to store to database")
+	if err := db.Put(validatorSnapshotKey(v.Address), bytes); err != nil {
+		utils.Logger().Error().Msg("[WriteValidatorSnapshot] Failed to store to database")
+		return err
 	}
 	return err
 }
 
+// DeleteValidatorSnapshot removes the validator's snapshot by its address
+func DeleteValidatorSnapshot(db DatabaseDeleter, addr common.Address) {
+	if err := db.Delete(validatorSnapshotKey(addr)); err != nil {
+		utils.Logger().Error().Msg("Failed to delete snapshot of a validator")
+	}
+}
+
 // ReadValidatorList retrieves staking validator by its address
-func ReadValidatorList(db DatabaseReader) ([]common.Address, error) {
-	data, err := db.Get([]byte("validatorList"))
-	if len(data) == 0 || err != nil {
+// Return only active validators if isActive==true, otherwise, return all validators
+func ReadValidatorList(db DatabaseReader, isActive bool) ([]common.Address, error) {
+	key := validatorListKey
+	if isActive {
+		key = activeValidatorListKey
+	}
+	data, err := db.Get(key)
+	if err != nil || len(data) == 0 {
 		return []common.Address{}, nil
 	}
 	addrs := []common.Address{}
@@ -656,12 +699,18 @@ func ReadValidatorList(db DatabaseReader) ([]common.Address, error) {
 }
 
 // WriteValidatorList stores staking validator's information by its address
-func WriteValidatorList(db DatabaseWriter, addrs []common.Address) error {
+// Writes only for active validators if isActive==true, otherwise, writes for all validators
+func WriteValidatorList(db DatabaseWriter, addrs []common.Address, isActive bool) error {
+	key := validatorListKey
+	if isActive {
+		key = activeValidatorListKey
+	}
+
 	bytes, err := rlp.EncodeToBytes(addrs)
 	if err != nil {
 		utils.Logger().Error().Msg("[WriteValidatorList] Failed to encode")
 	}
-	if err := db.Put([]byte("validatorList"), bytes); err != nil {
+	if err := db.Put(key, bytes); err != nil {
 		utils.Logger().Error().Msg("[WriteValidatorList] Failed to store to database")
 	}
 	return err
@@ -670,7 +719,7 @@ func WriteValidatorList(db DatabaseWriter, addrs []common.Address) error {
 // ReadValidatorListByDelegator retrieves the list of validators delegated by a delegator
 func ReadValidatorListByDelegator(db DatabaseReader, delegator common.Address) ([]common.Address, error) {
 	data, err := db.Get(delegatorValidatorListKey(delegator))
-	if len(data) == 0 || err != nil {
+	if err != nil || len(data) == 0 {
 		return []common.Address{}, nil
 	}
 	addrs := []common.Address{}
diff --git a/core/rawdb/schema.go b/core/rawdb/schema.go
index 3a4225f61..66c628f0b 100644
--- a/core/rawdb/schema.go
+++ b/core/rawdb/schema.go
@@ -74,7 +74,10 @@ var (
 	cxReceiptSpentPrefix             = []byte("cxReceiptSpent")             // prefix for indicator of unspent of cxReceiptsProof
 	cxReceiptUnspentCheckpointPrefix = []byte("cxReceiptUnspentCheckpoint") // prefix for cxReceiptsProof unspent checkpoint
 
-	stakingPrefix = []byte("staking") // prefix for staking validator information
+	validatorPrefix         = []byte("validator-")            // prefix for staking validator information
+	validatorSnapshotPrefix = []byte("validator-snapshot-")   // prefix for staking validator's snapshot information
+	validatorListKey        = []byte("validator-list")        // key for all validators list
+	activeValidatorListKey  = []byte("active-validator-list") // key for active validators list
 
 	// epochBlockNumberPrefix + epoch (big.Int.Bytes())
 	// -> epoch block number (big.Int.Bytes())
@@ -237,7 +240,12 @@ func cxReceiptUnspentCheckpointKey(shardID uint32) []byte {
 	return append(prefix, sKey...)
 }
 
-func stakingKey(addr common.Address) []byte {
-	prefix := stakingPrefix
+func validatorKey(addr common.Address) []byte {
+	prefix := validatorPrefix
+	return append(prefix, addr.Bytes()...)
+}
+
+func validatorSnapshotKey(addr common.Address) []byte {
+	prefix := validatorSnapshotPrefix
 	return append(prefix, addr.Bytes()...)
 }
diff --git a/core/state_transition.go b/core/state_transition.go
index 9b8a92bb8..f076d02b2 100644
--- a/core/state_transition.go
+++ b/core/state_transition.go
@@ -354,7 +354,7 @@ func (st *StateTransition) applyCreateValidatorTx(createValidator *staking.Creat
 	delegations := []staking.Delegation{}
 	delegations = append(delegations, staking.NewDelegation(v.Address, createValidator.Amount))
 
-	wrapper := staking.ValidatorWrapper{*v, delegations, nil, nil}
+	wrapper := staking.ValidatorWrapper{*v, delegations}
 
 	if err := st.state.UpdateStakingInfo(v.Address, &wrapper); err != nil {
 		return err
diff --git a/hmy/api_backend.go b/hmy/api_backend.go
index f22857630..d7d05b9dd 100644
--- a/hmy/api_backend.go
+++ b/hmy/api_backend.go
@@ -290,9 +290,9 @@ func (b *APIBackend) SendStakingTx(
 	return nil
 }
 
-// GetCurrentValidatorAddresses returns the address of active validators for current epoch
-func (b *APIBackend) GetCurrentValidatorAddresses() []common.Address {
-	return b.hmy.BlockChain().CurrentValidatorAddresses()
+// GetActiveValidatorAddresses returns the address of active validators for current epoch
+func (b *APIBackend) GetActiveValidatorAddresses() []common.Address {
+	return b.hmy.BlockChain().ActiveValidatorAddresses()
 }
 
 // GetValidatorCandidates returns the up to date validator candidates for next epoch
diff --git a/internal/chain/engine.go b/internal/chain/engine.go
index ee6bc7289..b3b647377 100644
--- a/internal/chain/engine.go
+++ b/internal/chain/engine.go
@@ -179,7 +179,7 @@ func (e *engineImpl) Finalize(
 	// Only do such at the last block of an epoch
 	if len(header.ShardState()) > 0 {
 		// TODO: make sure we are using the correct validator list
-		validators := chain.CurrentValidatorAddresses()
+		validators := chain.ActiveValidatorAddresses()
 		for _, validator := range validators {
 			wrapper := state.GetStakingInfo(validator)
 			if wrapper != nil {
@@ -227,7 +227,7 @@ func QuorumForBlock(chain engine.ChainReader, h *block.Header, reCalculate bool)
 		return 0, errors.Errorf(
 			"cannot find shard %d in shard state", h.ShardID())
 	}
-	return (len(c.NodeList))*2/3 + 1, nil
+	return (len(c.Slots))*2/3 + 1, nil
 }
 
 // Similiar to VerifyHeader, which is only for verifying the block headers of one's own chain, this verification
@@ -289,7 +289,7 @@ func GetPublicKeys(chain engine.ChainReader, header *block.Header, reCalculate b
 		)
 	}
 	var committerKeys []*bls.PublicKey
-	for _, member := range committee.NodeList {
+	for _, member := range committee.Slots {
 		committerKey := new(bls.PublicKey)
 		err := member.BlsPublicKey.ToLibBLSPublicKey(committerKey)
 		if err != nil {
diff --git a/internal/chain/reward.go b/internal/chain/reward.go
index c4f585161..a6a9e952f 100644
--- a/internal/chain/reward.go
+++ b/internal/chain/reward.go
@@ -61,7 +61,7 @@ func AccumulateRewards(
 		)
 	}
 	var committerKeys []*bls.PublicKey
-	for _, member := range parentCommittee.NodeList {
+	for _, member := range parentCommittee.Slots {
 		committerKey := new(bls.PublicKey)
 		err := member.BlsPublicKey.ToLibBLSPublicKey(committerKey)
 		if err != nil {
@@ -80,7 +80,7 @@ func AccumulateRewards(
 
 	accounts := []common.Address{}
 
-	for idx, member := range parentCommittee.NodeList {
+	for idx, member := range parentCommittee.Slots {
 		if signed, err := mask.IndexEnabled(idx); err != nil {
 			return ctxerror.New("cannot check for committer bit",
 				"committerIndex", idx,
diff --git a/internal/hmyapi/backend.go b/internal/hmyapi/backend.go
index deaefbb2a..f8dbdcdb4 100644
--- a/internal/hmyapi/backend.go
+++ b/internal/hmyapi/backend.go
@@ -73,7 +73,7 @@ type Backend interface {
 	ResendCx(ctx context.Context, txID common.Hash) (uint64, bool)
 	IsLeader() bool
 	SendStakingTx(ctx context.Context, newStakingTx *staking.StakingTransaction) error
-	GetCurrentValidatorAddresses() []common.Address
+	GetActiveValidatorAddresses() []common.Address
 	GetValidatorCandidates() []common.Address
 	GetValidatorInformation(addr common.Address) *staking.Validator
 	GetDelegatorsInformation(addr common.Address) []*staking.Delegation
diff --git a/internal/hmyapi/blockchain.go b/internal/hmyapi/blockchain.go
index ab7ade411..a95f436db 100644
--- a/internal/hmyapi/blockchain.go
+++ b/internal/hmyapi/blockchain.go
@@ -153,7 +153,7 @@ func (s *PublicBlockChainAPI) GetValidators(ctx context.Context, epoch int64) (m
 		return nil, err
 	}
 	validators := make([]map[string]interface{}, 0)
-	for _, validator := range committee.NodeList {
+	for _, validator := range committee.Slots {
 		validatorBalance := new(hexutil.Big)
 		validatorBalance, err = s.b.GetBalance(validator.EcdsaAddress)
 		if err != nil {
@@ -193,8 +193,8 @@ func (s *PublicBlockChainAPI) GetBlockSigners(ctx context.Context, blockNr rpc.B
 	if err != nil {
 		return nil, err
 	}
-	pubkeys := make([]*bls.PublicKey, len(committee.NodeList))
-	for i, validator := range committee.NodeList {
+	pubkeys := make([]*bls.PublicKey, len(committee.Slots))
+	for i, validator := range committee.Slots {
 		pubkeys[i] = new(bls.PublicKey)
 		validator.BlsPublicKey.ToLibBLSPublicKey(pubkeys[i])
 	}
@@ -210,7 +210,7 @@ func (s *PublicBlockChainAPI) GetBlockSigners(ctx context.Context, blockNr rpc.B
 	if err != nil {
 		return result, err
 	}
-	for _, validator := range committee.NodeList {
+	for _, validator := range committee.Slots {
 		oneAddress, err := internal_common.AddressToBech32(validator.EcdsaAddress)
 		if err != nil {
 			return result, err
@@ -241,8 +241,8 @@ func (s *PublicBlockChainAPI) IsBlockSigner(ctx context.Context, blockNr rpc.Blo
 	if err != nil {
 		return false, err
 	}
-	pubkeys := make([]*bls.PublicKey, len(committee.NodeList))
-	for i, validator := range committee.NodeList {
+	pubkeys := make([]*bls.PublicKey, len(committee.Slots))
+	for i, validator := range committee.Slots {
 		pubkeys[i] = new(bls.PublicKey)
 		validator.BlsPublicKey.ToLibBLSPublicKey(pubkeys[i])
 	}
@@ -254,7 +254,7 @@ func (s *PublicBlockChainAPI) IsBlockSigner(ctx context.Context, blockNr rpc.Blo
 	if err != nil {
 		return false, err
 	}
-	for _, validator := range committee.NodeList {
+	for _, validator := range committee.Slots {
 		oneAddress, err := internal_common.AddressToBech32(validator.EcdsaAddress)
 		if err != nil {
 			return false, err
diff --git a/node/node_cross_shard.go b/node/node_cross_shard.go
index ee306c389..0e97e877d 100644
--- a/node/node_cross_shard.go
+++ b/node/node_cross_shard.go
@@ -298,7 +298,7 @@ func (node *Node) VerifyCrosslinkHeader(prevHeader, header *block.Header) error
 	var committerKeys []*bls.PublicKey
 
 	parseKeysSuccess := true
-	for _, member := range committee.NodeList {
+	for _, member := range committee.Slots {
 		committerKey := new(bls.PublicKey)
 		err = member.BlsPublicKey.ToLibBLSPublicKey(committerKey)
 		if err != nil {
diff --git a/node/node_handler.go b/node/node_handler.go
index e79ca00e3..89402cb6c 100644
--- a/node/node_handler.go
+++ b/node/node_handler.go
@@ -411,7 +411,7 @@ func (node *Node) AddNewBlock(newBlock *types.Block) error {
 			}
 			utils.Logger().Debug().Msgf("ValidatorInformation %v: %v", i, val)
 		}
-		currAddrs := node.Blockchain().CurrentValidatorAddresses()
+		currAddrs := node.Blockchain().ActiveValidatorAddresses()
 		utils.Logger().Debug().Msgf("CurrentValidators : %v", currAddrs)
 		candidates := node.Blockchain().ValidatorCandidates()
 		utils.Logger().Debug().Msgf("CandidateValidators : %v", candidates)
diff --git a/node/node_resharding.go b/node/node_resharding.go
index 6ac62c807..bd2a6d410 100644
--- a/node/node_resharding.go
+++ b/node/node_resharding.go
@@ -201,7 +201,7 @@ func (node *Node) transitionIntoNextEpoch(shardState types.State) {
 	for _, c := range shardState {
 		utils.Logger().Debug().
 			Uint32("shardID", c.ShardID).
-			Str("nodeList", c.NodeList).
+			Str("nodeList", c.Slots).
          Msg("new shard information")
 	}
 	myShardID, isNextLeader := findRoleInShardState(
@@ -219,7 +219,7 @@ func (node *Node) transitionIntoNextEpoch(shardState types.State) {
 
 	// Update public keys
 	var publicKeys []*bls.PublicKey
-	for idx, nodeID := range myShardState.NodeList {
+	for idx, nodeID := range myShardState.Slots {
 		key := &bls.PublicKey{}
 		err := key.Deserialize(nodeID.BlsPublicKey[:])
 		if err != nil {
@@ -249,7 +249,7 @@ func findRoleInShardState(
 ) (shardID uint32, isLeader bool) {
 	keyBytes := key.Serialize()
 	for idx, shard := range state {
-		for nodeIdx, nodeID := range shard.NodeList {
+		for nodeIdx, nodeID := range shard.Slots {
 			if bytes.Compare(nodeID.BlsPublicKey[:], keyBytes) == 0 {
 				return uint32(idx), nodeIdx == 0
 			}
diff --git a/shard/committee/assignment.go b/shard/committee/assignment.go
index 7abcbaea3..f7cdb75ed 100644
--- a/shard/committee/assignment.go
+++ b/shard/committee/assignment.go
@@ -85,12 +85,12 @@ func preStakingEnabledCommittee(s shardingconfig.Instance) shard.State {
 			pubKey := shard.BlsPublicKey{}
 			pubKey.FromLibBLSPublicKey(pub)
 			// TODO: directly read address for bls too
-			curNodeID := shard.NodeID{
+			curNodeID := shard.Slot{
 				common2.ParseAddr(hmyAccounts[index].Address),
 				pubKey,
 				nil,
 			}
-			com.NodeList = append(com.NodeList, curNodeID)
+			com.Slots = append(com.Slots, curNodeID)
 		}
 		// add FN runner's key
 		for j := shardHarmonyNodes; j < shardSize; j++ {
@@ -100,12 +100,12 @@ func preStakingEnabledCommittee(s shardingconfig.Instance) shard.State {
 			pubKey := shard.BlsPublicKey{}
 			pubKey.FromLibBLSPublicKey(pub)
 			// TODO: directly read address for bls too
-			curNodeID := shard.NodeID{
+			curNodeID := shard.Slot{
 				common2.ParseAddr(fnAccounts[index].Address),
 				pubKey,
 				nil,
 			}
-			com.NodeList = append(com.NodeList, curNodeID)
+			com.Slots = append(com.Slots, curNodeID)
 		}
 		shardState = append(shardState, com)
 	}
@@ -137,7 +137,7 @@ func eposStakedCommittee(
 	hAccounts := s.HmyAccounts()
 
 	for i := 0; i < shardCount; i++ {
-		superComm[i] = shard.Committee{uint32(i), shard.NodeIDList{}}
+		superComm[i] = shard.Committee{uint32(i), shard.SlotList{}}
 	}
 
 	for i := range hAccounts {
@@ -146,7 +146,7 @@ func eposStakedCommittee(
 		pub.DeserializeHexStr(hAccounts[i].BlsPublicKey)
 		pubKey := shard.BlsPublicKey{}
 		pubKey.FromLibBLSPublicKey(pub)
-		superComm[spot].NodeList = append(superComm[spot].NodeList, shard.NodeID{
+		superComm[spot].Slots = append(superComm[spot].Slots, shard.Slot{
 			common2.ParseAddr(hAccounts[i].Address),
 			pubKey,
 			nil,
@@ -164,7 +164,7 @@ func eposStakedCommittee(
 	for i := 0; i < stakedSlotsCount; i++ {
 		bucket := int(new(big.Int).Mod(staked[i].BlsPublicKey.Big(), shardBig).Int64())
 		slot := staked[i]
-		superComm[bucket].NodeList = append(superComm[bucket].NodeList, shard.NodeID{
+		superComm[bucket].Slots = append(superComm[bucket].Slots, shard.Slot{
 			slot.Address,
 			staked[i].BlsPublicKey,
 			&slot.Dec,
@@ -191,10 +191,10 @@ func (def partialStakingEnabled) ComputePublicKeys(
 	allIdentities := make([][]*bls.PublicKey, len(superComm))
 
 	for i := range superComm {
-		allIdentities[i] = make([]*bls.PublicKey, len(superComm[i].NodeList))
-		for j := range superComm[i].NodeList {
+		allIdentities[i] = make([]*bls.PublicKey, len(superComm[i].Slots))
+		for j := range superComm[i].Slots {
 			identity := &bls.PublicKey{}
-			superComm[i].NodeList[j].BlsPublicKey.ToLibBLSPublicKey(identity)
+			superComm[i].Slots[j].BlsPublicKey.ToLibBLSPublicKey(identity)
 			allIdentities[i][j] = identity
 		}
 	}
@@ -220,12 +220,12 @@ func (def partialStakingEnabled) ReadPublicKeysFromDB(
 	}
 	committerKeys := []*bls.PublicKey{}
 
-	for i := range subCommittee.NodeList {
+	for i := range subCommittee.Slots {
 		committerKey := new(bls.PublicKey)
-		err := subCommittee.NodeList[i].BlsPublicKey.ToLibBLSPublicKey(committerKey)
+		err := subCommittee.Slots[i].BlsPublicKey.ToLibBLSPublicKey(committerKey)
 		if err != nil {
 			return nil, ctxerror.New("cannot convert BLS public key",
-				"blsPublicKey", subCommittee.NodeList[i].BlsPublicKey).WithCause(err)
+				"blsPublicKey", subCommittee.Slots[i].BlsPublicKey).WithCause(err)
 		}
 		committerKeys = append(committerKeys, committerKey)
 	}
diff --git a/shard/shard_state.go b/shard/shard_state.go
index b8bccccf0..65644b0b0 100644
--- a/shard/shard_state.go
+++ b/shard/shard_state.go
@@ -34,27 +34,27 @@ type State []Committee
 // BlsPublicKey defines the bls public key
 type BlsPublicKey [PublicKeySizeInBytes]byte
 
-// NodeID represents node id (BLS address)
-type NodeID struct {
+// Slot represents node id (BLS address)
+type Slot struct {
 	EcdsaAddress common.Address `json:"ecdsa-address"`
 	BlsPublicKey BlsPublicKey   `json:"bls-pubkey"`
 	// nil means not active, 0 means our node, >= 0 means staked node
 	StakeWithDelegationApplied *numeric.Dec `json:"staked-validator" rlp:"nil"`
 }
 
-// NodeIDList is a list of NodeIDList.
-type NodeIDList []NodeID
+// SlotList is a list of SlotList.
+type SlotList []Slot
 
 // Committee contains the active nodes in one shard
 type Committee struct {
-	ShardID  uint32     `json:"shard-id"`
-	NodeList NodeIDList `json:"subcommittee"`
+	ShardID uint32   `json:"shard-id"`
+	Slots   SlotList `json:"subcommittee"`
 }
 
 // JSON produces a non-pretty printed JSON string of the SuperCommittee
 func (ss State) JSON() string {
 	type t struct {
-		NodeID
+		Slot
 		EcdsaAddress string `json:"one-address"`
 	}
 	type v struct {
@@ -64,12 +64,12 @@ func (ss State) JSON() string {
 	}
 	dump := make([]v, len(ss))
 	for i := range ss {
-		c := len(ss[i].NodeList)
+		c := len(ss[i].Slots)
 		dump[i].ShardID = ss[i].ShardID
 		dump[i].NodeList = make([]t, c)
 		dump[i].Count = c
-		for j := range ss[i].NodeList {
-			n := ss[i].NodeList[j]
+		for j := range ss[i].Slots {
+			n := ss[i].Slots[j]
 			dump[i].NodeList[j].BlsPublicKey = n.BlsPublicKey
 			dump[i].NodeList[j].StakeWithDelegationApplied = n.StakeWithDelegationApplied
 			dump[i].NodeList[j].EcdsaAddress = common2.MustAddressToBech32(n.EcdsaAddress)
@@ -166,7 +166,7 @@ func CompareBlsPublicKey(k1, k2 BlsPublicKey) int {
 }
 
 // CompareNodeID compares two node IDs.
-func CompareNodeID(id1, id2 *NodeID) int {
+func CompareNodeID(id1, id2 *Slot) int {
 	if c := bytes.Compare(id1.EcdsaAddress[:], id2.EcdsaAddress[:]); c != 0 {
 		return c
 	}
@@ -177,12 +177,12 @@ func CompareNodeID(id1, id2 *NodeID) int {
 }
 
 // DeepCopy returns a deep copy of the receiver.
-func (l NodeIDList) DeepCopy() NodeIDList {
+func (l SlotList) DeepCopy() SlotList {
 	return append(l[:0:0], l...)
 }
 
 // CompareNodeIDList compares two node ID lists.
-func CompareNodeIDList(l1, l2 NodeIDList) int {
+func CompareNodeIDList(l1, l2 SlotList) int {
 	commonLen := len(l1)
 	if commonLen > len(l2) {
 		commonLen = len(l2)
@@ -205,7 +205,7 @@ func CompareNodeIDList(l1, l2 NodeIDList) int {
 func (c Committee) DeepCopy() Committee {
 	r := Committee{}
 	r.ShardID = c.ShardID
-	r.NodeList = c.NodeList.DeepCopy()
+	r.Slots = c.Slots.DeepCopy()
 	return r
 }
 
@@ -217,7 +217,7 @@ func CompareCommittee(c1, c2 *Committee) int {
 	case c1.ShardID > c2.ShardID:
 		return +1
 	}
-	if c := CompareNodeIDList(c1.NodeList, c2.NodeList); c != 0 {
+	if c := CompareNodeIDList(c1.Slots, c2.Slots); c != 0 {
 		return c
 	}
 	return 0
@@ -225,7 +225,7 @@ func CompareCommittee(c1, c2 *Committee) int {
 
 // GetHashFromNodeList will sort the list, then use Keccak256 to hash the list
 // NOTE: do not modify the underlining content for hash
-func GetHashFromNodeList(nodeList []NodeID) []byte {
+func GetHashFromNodeList(nodeList []Slot) []byte {
 	// in general, nodeList should not be empty
 	if nodeList == nil || len(nodeList) == 0 {
 		return []byte{}
@@ -248,7 +248,7 @@ func (ss State) Hash() (h common.Hash) {
 	})
 	d := sha3.NewLegacyKeccak256()
 	for i := range copy {
-		hash := GetHashFromNodeList(copy[i].NodeList)
+		hash := GetHashFromNodeList(copy[i].Slots)
 		d.Write(hash)
 	}
 	d.Sum(h[:0])
@@ -256,15 +256,15 @@ func (ss State) Hash() (h common.Hash) {
 }
 
 // CompareNodeIDByBLSKey compares two nodes by their ID; used to sort node list
-func CompareNodeIDByBLSKey(n1 NodeID, n2 NodeID) int {
+func CompareNodeIDByBLSKey(n1 Slot, n2 Slot) int {
 	return bytes.Compare(n1.BlsPublicKey[:], n2.BlsPublicKey[:])
 }
 
-// Serialize serialize NodeID into bytes
-func (n NodeID) Serialize() []byte {
+// Serialize serialize Slot into bytes
+func (n Slot) Serialize() []byte {
 	return append(n.EcdsaAddress[:], n.BlsPublicKey[:]...)
 }
 
-func (n NodeID) String() string {
+func (n Slot) String() string {
 	return "ECDSA: " + common2.MustAddressToBech32(n.EcdsaAddress) + ", BLS: " + hex.EncodeToString(n.BlsPublicKey[:])
 }
diff --git a/shard/shard_state_test.go b/shard/shard_state_test.go
index 12ce1784d..8f55e1782 100644
--- a/shard/shard_state_test.go
+++ b/shard/shard_state_test.go
@@ -30,12 +30,12 @@ func init() {
 }
 
 func TestGetHashFromNodeList(t *testing.T) {
-	l1 := []NodeID{
+	l1 := []Slot{
 		{common.Address{0x11}, blsPubKey1, nil},
 		{common.Address{0x22}, blsPubKey2, nil},
 		{common.Address{0x33}, blsPubKey3, nil},
 	}
-	l2 := []NodeID{
+	l2 := []Slot{
 		{common.Address{0x22}, blsPubKey2, nil},
 		{common.Address{0x11}, blsPubKey1, nil},
 		{common.Address{0x33}, blsPubKey3, nil},
@@ -51,7 +51,7 @@ func TestGetHashFromNodeList(t *testing.T) {
 func TestHash(t *testing.T) {
 	com1 := Committee{
 		ShardID: 22,
-		NodeList: []NodeID{
+		Slots: []Slot{
 			{common.Address{0x12}, blsPubKey11, nil},
 			{common.Address{0x23}, blsPubKey22, nil},
 			{common.Address{0x11}, blsPubKey1, nil},
@@ -59,7 +59,7 @@ func TestHash(t *testing.T) {
 	}
 	com2 := Committee{
 		ShardID: 2,
-		NodeList: []NodeID{
+		Slots: []Slot{
 			{common.Address{0x44}, blsPubKey4, nil},
 			{common.Address{0x55}, blsPubKey5, nil},
 			{common.Address{0x66}, blsPubKey6, nil},
@@ -70,7 +70,7 @@ func TestHash(t *testing.T) {
 
 	com3 := Committee{
 		ShardID: 2,
-		NodeList: []NodeID{
+		Slots: []Slot{
 			{common.Address{0x44}, blsPubKey4, nil},
 			{common.Address{0x55}, blsPubKey5, nil},
 			{common.Address{0x66}, blsPubKey6, nil},
@@ -78,7 +78,7 @@ func TestHash(t *testing.T) {
 	}
 	com4 := Committee{
 		ShardID: 22,
-		NodeList: []NodeID{
+		Slots: []Slot{
 			{common.Address{0x12}, blsPubKey11, nil},
 			{common.Address{0x23}, blsPubKey22, nil},
 			{common.Address{0x11}, blsPubKey1, nil},
diff --git a/staking/types/validator.go b/staking/types/validator.go
index 9d7d93458..2ca0b8a1b 100644
--- a/staking/types/validator.go
+++ b/staking/types/validator.go
@@ -36,9 +36,6 @@ var (
 type ValidatorWrapper struct {
 	Validator   `json:"validator" yaml:"validator" rlp:"nil"`
 	Delegations []Delegation `json:"delegations" yaml:"delegations" rlp:"nil"`
-	// TODO: move snapshot into off-chain db.
-	SnapshotValidator   *Validator   `json:"snapshot_validator" yaml:"snaphost_validator" rlp:"nil"`
-	SnapshotDelegations []Delegation `json:"snapshot_delegations" yaml:"snapshot_delegations" rlp:"nil"`
 }
 
 // Validator - data fields for a validator