From 78745551c077bf54151202138c2629f288769561 Mon Sep 17 00:00:00 2001
From: Determinant <tederminant@gmail.com>
Date: Tue, 15 Sep 2020 23:55:34 -0400
Subject: WIP: geth-tavum

---
 core/rawdb/accessors_indexes.go  |  68 ++++++++++++++++---
 core/rawdb/accessors_metadata.go |  25 ++-----
 core/rawdb/accessors_snapshot.go | 120 +++++++++++++++++++++++++++++++++
 core/rawdb/database.go           |  61 ++++++++++++-----
 core/rawdb/freezer.go            | 141 ++++++++++++++++++++++++++++++---------
 core/rawdb/freezer_reinit.go     | 127 -----------------------------------
 core/rawdb/freezer_table.go      |  72 ++++++++++++--------
 core/rawdb/schema.go             |  56 ++++++++++++++--
 core/rawdb/table.go              |  93 ++++++++++++++++++++------
 9 files changed, 508 insertions(+), 255 deletions(-)
 create mode 100644 core/rawdb/accessors_snapshot.go
 delete mode 100644 core/rawdb/freezer_reinit.go

(limited to 'core/rawdb')

diff --git a/core/rawdb/accessors_indexes.go b/core/rawdb/accessors_indexes.go
index 1dd478a..bf3ba07 100644
--- a/core/rawdb/accessors_indexes.go
+++ b/core/rawdb/accessors_indexes.go
@@ -17,14 +17,15 @@
 package rawdb
 
 import (
+	"bytes"
 	"math/big"
 
 	"github.com/ava-labs/coreth/core/types"
 	"github.com/ava-labs/coreth/params"
-	"github.com/ava-labs/go-ethereum/common"
-	"github.com/ava-labs/go-ethereum/ethdb"
-	"github.com/ava-labs/go-ethereum/log"
-	"github.com/ava-labs/go-ethereum/rlp"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/ethdb"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/rlp"
 )
 
 // ReadTxLookupEntry retrieves the positional metadata associated with a transaction
@@ -52,20 +53,44 @@ func ReadTxLookupEntry(db ethdb.Reader, hash common.Hash) *uint64 {
 	return &entry.BlockIndex
 }
 
-// WriteTxLookupEntries stores a positional metadata for every transaction from
+// writeTxLookupEntry stores a positional metadata for a transaction,
+// enabling hash based transaction and receipt lookups.
+func writeTxLookupEntry(db ethdb.KeyValueWriter, hash common.Hash, numberBytes []byte) {
+	if err := db.Put(txLookupKey(hash), numberBytes); err != nil {
+		log.Crit("Failed to store transaction lookup entry", "err", err)
+	}
+}
+
+// WriteTxLookupEntries is identical to WriteTxLookupEntry, but it works on
+// a list of hashes
+func WriteTxLookupEntries(db ethdb.KeyValueWriter, number uint64, hashes []common.Hash) {
+	numberBytes := new(big.Int).SetUint64(number).Bytes()
+	for _, hash := range hashes {
+		writeTxLookupEntry(db, hash, numberBytes)
+	}
+}
+
+// WriteTxLookupEntriesByBlock stores a positional metadata for every transaction from
 // a block, enabling hash based transaction and receipt lookups.
-func WriteTxLookupEntries(db ethdb.KeyValueWriter, block *types.Block) {
-	number := block.Number().Bytes()
+func WriteTxLookupEntriesByBlock(db ethdb.KeyValueWriter, block *types.Block) {
+	numberBytes := block.Number().Bytes()
 	for _, tx := range block.Transactions() {
-		if err := db.Put(txLookupKey(tx.Hash()), number); err != nil {
-			log.Crit("Failed to store transaction lookup entry", "err", err)
-		}
+		writeTxLookupEntry(db, tx.Hash(), numberBytes)
 	}
 }
 
 // DeleteTxLookupEntry removes all transaction data associated with a hash.
 func DeleteTxLookupEntry(db ethdb.KeyValueWriter, hash common.Hash) {
-	db.Delete(txLookupKey(hash))
+	if err := db.Delete(txLookupKey(hash)); err != nil {
+		log.Crit("Failed to delete transaction lookup entry", "err", err)
+	}
+}
+
+// DeleteTxLookupEntries removes all transaction lookups for a given block.
+func DeleteTxLookupEntries(db ethdb.KeyValueWriter, hashes []common.Hash) {
+	for _, hash := range hashes {
+		DeleteTxLookupEntry(db, hash)
+	}
 }
 
 // ReadTransaction retrieves a specific transaction from the database, along with
@@ -129,3 +154,24 @@ func WriteBloomBits(db ethdb.KeyValueWriter, bit uint, section uint64, head comm
 		log.Crit("Failed to store bloom bits", "err", err)
 	}
 }
+
+// DeleteBloombits removes all compressed bloom bits vector belonging to the
+// given section range and bit index.
+func DeleteBloombits(db ethdb.Database, bit uint, from uint64, to uint64) {
+	start, end := bloomBitsKey(bit, from, common.Hash{}), bloomBitsKey(bit, to, common.Hash{})
+	it := db.NewIterator(nil, start)
+	defer it.Release()
+
+	for it.Next() {
+		if bytes.Compare(it.Key(), end) >= 0 {
+			break
+		}
+		if len(it.Key()) != len(bloomBitsPrefix)+2+8+32 {
+			continue
+		}
+		db.Delete(it.Key())
+	}
+	if it.Error() != nil {
+		log.Crit("Failed to delete bloom bits", "err", it.Error())
+	}
+}
diff --git a/core/rawdb/accessors_metadata.go b/core/rawdb/accessors_metadata.go
index 7a17123..c5e5655 100644
--- a/core/rawdb/accessors_metadata.go
+++ b/core/rawdb/accessors_metadata.go
@@ -20,10 +20,10 @@ import (
 	"encoding/json"
 
 	"github.com/ava-labs/coreth/params"
-	"github.com/ava-labs/go-ethereum/common"
-	"github.com/ava-labs/go-ethereum/ethdb"
-	"github.com/ava-labs/go-ethereum/log"
-	"github.com/ava-labs/go-ethereum/rlp"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/ethdb"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/rlp"
 )
 
 // ReadDatabaseVersion retrieves the version number of the database.
@@ -79,20 +79,3 @@ func WriteChainConfig(db ethdb.KeyValueWriter, hash common.Hash, cfg *params.Cha
 		log.Crit("Failed to store chain config", "err", err)
 	}
 }
-
-// ReadPreimage retrieves a single preimage of the provided hash.
-func ReadPreimage(db ethdb.KeyValueReader, hash common.Hash) []byte {
-	data, _ := db.Get(preimageKey(hash))
-	return data
-}
-
-// WritePreimages writes the provided set of preimages to the database.
-func WritePreimages(db ethdb.KeyValueWriter, preimages map[common.Hash][]byte) {
-	for hash, preimage := range preimages {
-		if err := db.Put(preimageKey(hash), preimage); err != nil {
-			log.Crit("Failed to store trie preimage", "err", err)
-		}
-	}
-	preimageCounter.Inc(int64(len(preimages)))
-	preimageHitCounter.Inc(int64(len(preimages)))
-}
diff --git a/core/rawdb/accessors_snapshot.go b/core/rawdb/accessors_snapshot.go
new file mode 100644
index 0000000..ecd4e65
--- /dev/null
+++ b/core/rawdb/accessors_snapshot.go
@@ -0,0 +1,120 @@
+// Copyright 2019 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package rawdb
+
+import (
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/ethdb"
+	"github.com/ethereum/go-ethereum/log"
+)
+
+// ReadSnapshotRoot retrieves the root of the block whose state is contained in
+// the persisted snapshot.
+func ReadSnapshotRoot(db ethdb.KeyValueReader) common.Hash {
+	data, _ := db.Get(snapshotRootKey)
+	if len(data) != common.HashLength {
+		return common.Hash{}
+	}
+	return common.BytesToHash(data)
+}
+
+// WriteSnapshotRoot stores the root of the block whose state is contained in
+// the persisted snapshot.
+func WriteSnapshotRoot(db ethdb.KeyValueWriter, root common.Hash) {
+	if err := db.Put(snapshotRootKey, root[:]); err != nil {
+		log.Crit("Failed to store snapshot root", "err", err)
+	}
+}
+
+// DeleteSnapshotRoot deletes the hash of the block whose state is contained in
+// the persisted snapshot. Since snapshots are not immutable, this  method can
+// be used during updates, so a crash or failure will mark the entire snapshot
+// invalid.
+func DeleteSnapshotRoot(db ethdb.KeyValueWriter) {
+	if err := db.Delete(snapshotRootKey); err != nil {
+		log.Crit("Failed to remove snapshot root", "err", err)
+	}
+}
+
+// ReadAccountSnapshot retrieves the snapshot entry of an account trie leaf.
+func ReadAccountSnapshot(db ethdb.KeyValueReader, hash common.Hash) []byte {
+	data, _ := db.Get(accountSnapshotKey(hash))
+	return data
+}
+
+// WriteAccountSnapshot stores the snapshot entry of an account trie leaf.
+func WriteAccountSnapshot(db ethdb.KeyValueWriter, hash common.Hash, entry []byte) {
+	if err := db.Put(accountSnapshotKey(hash), entry); err != nil {
+		log.Crit("Failed to store account snapshot", "err", err)
+	}
+}
+
+// DeleteAccountSnapshot removes the snapshot entry of an account trie leaf.
+func DeleteAccountSnapshot(db ethdb.KeyValueWriter, hash common.Hash) {
+	if err := db.Delete(accountSnapshotKey(hash)); err != nil {
+		log.Crit("Failed to delete account snapshot", "err", err)
+	}
+}
+
+// ReadStorageSnapshot retrieves the snapshot entry of an storage trie leaf.
+func ReadStorageSnapshot(db ethdb.KeyValueReader, accountHash, storageHash common.Hash) []byte {
+	data, _ := db.Get(storageSnapshotKey(accountHash, storageHash))
+	return data
+}
+
+// WriteStorageSnapshot stores the snapshot entry of an storage trie leaf.
+func WriteStorageSnapshot(db ethdb.KeyValueWriter, accountHash, storageHash common.Hash, entry []byte) {
+	if err := db.Put(storageSnapshotKey(accountHash, storageHash), entry); err != nil {
+		log.Crit("Failed to store storage snapshot", "err", err)
+	}
+}
+
+// DeleteStorageSnapshot removes the snapshot entry of an storage trie leaf.
+func DeleteStorageSnapshot(db ethdb.KeyValueWriter, accountHash, storageHash common.Hash) {
+	if err := db.Delete(storageSnapshotKey(accountHash, storageHash)); err != nil {
+		log.Crit("Failed to delete storage snapshot", "err", err)
+	}
+}
+
+// IterateStorageSnapshots returns an iterator for walking the entire storage
+// space of a specific account.
+func IterateStorageSnapshots(db ethdb.Iteratee, accountHash common.Hash) ethdb.Iterator {
+	return db.NewIterator(storageSnapshotsKey(accountHash), nil)
+}
+
+// ReadSnapshotJournal retrieves the serialized in-memory diff layers saved at
+// the last shutdown. The blob is expected to be max a few 10s of megabytes.
+func ReadSnapshotJournal(db ethdb.KeyValueReader) []byte {
+	data, _ := db.Get(snapshotJournalKey)
+	return data
+}
+
+// WriteSnapshotJournal stores the serialized in-memory diff layers to save at
+// shutdown. The blob is expected to be max a few 10s of megabytes.
+func WriteSnapshotJournal(db ethdb.KeyValueWriter, journal []byte) {
+	if err := db.Put(snapshotJournalKey, journal); err != nil {
+		log.Crit("Failed to store snapshot journal", "err", err)
+	}
+}
+
+// DeleteSnapshotJournal deletes the serialized in-memory diff layers saved at
+// the last shutdown
+func DeleteSnapshotJournal(db ethdb.KeyValueWriter) {
+	if err := db.Delete(snapshotJournalKey); err != nil {
+		log.Crit("Failed to remove snapshot journal", "err", err)
+	}
+}
diff --git a/core/rawdb/database.go b/core/rawdb/database.go
index f04c34f..316b5ad 100644
--- a/core/rawdb/database.go
+++ b/core/rawdb/database.go
@@ -21,13 +21,14 @@ import (
 	"errors"
 	"fmt"
 	"os"
+	"sync/atomic"
 	"time"
 
-	"github.com/ava-labs/go-ethereum/common"
-	"github.com/ava-labs/go-ethereum/ethdb"
-	"github.com/ava-labs/go-ethereum/ethdb/leveldb"
-	"github.com/ava-labs/go-ethereum/ethdb/memorydb"
-	"github.com/ava-labs/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/ethdb"
+	"github.com/ethereum/go-ethereum/ethdb/leveldb"
+	"github.com/ethereum/go-ethereum/ethdb/memorydb"
+	"github.com/ethereum/go-ethereum/log"
 	"github.com/olekukonko/tablewriter"
 )
 
@@ -41,10 +42,10 @@ type freezerdb struct {
 // the slow ancient tables.
 func (frdb *freezerdb) Close() error {
 	var errs []error
-	if err := frdb.KeyValueStore.Close(); err != nil {
+	if err := frdb.AncientStore.Close(); err != nil {
 		errs = append(errs, err)
 	}
-	if err := frdb.AncientStore.Close(); err != nil {
+	if err := frdb.KeyValueStore.Close(); err != nil {
 		errs = append(errs, err)
 	}
 	if len(errs) != 0 {
@@ -53,6 +54,22 @@ func (frdb *freezerdb) Close() error {
 	return nil
 }
 
+// Freeze is a helper method used for external testing to trigger and block until
+// a freeze cycle completes, without having to sleep for a minute to trigger the
+// automatic background run.
+func (frdb *freezerdb) Freeze(threshold uint64) {
+	// Set the freezer threshold to a temporary value
+	defer func(old uint64) {
+		atomic.StoreUint64(&frdb.AncientStore.(*freezer).threshold, old)
+	}(atomic.LoadUint64(&frdb.AncientStore.(*freezer).threshold))
+	atomic.StoreUint64(&frdb.AncientStore.(*freezer).threshold, threshold)
+
+	// Trigger a freeze cycle and block until it's done
+	trigger := make(chan struct{}, 1)
+	frdb.AncientStore.(*freezer).trigger <- trigger
+	<-trigger
+}
+
 // nofreezedb is a database wrapper that disables freezer data retrievals.
 type nofreezedb struct {
 	ethdb.KeyValueStore
@@ -137,7 +154,10 @@ func NewDatabaseWithFreezer(db ethdb.KeyValueStore, freezer string, namespace st
 			// If the freezer already contains something, ensure that the genesis blocks
 			// match, otherwise we might mix up freezers across chains and destroy both
 			// the freezer and the key-value store.
-			if frgenesis, _ := frdb.Ancient(freezerHashTable, 0); !bytes.Equal(kvgenesis, frgenesis) {
+			frgenesis, err := frdb.Ancient(freezerHashTable, 0)
+			if err != nil {
+				return nil, fmt.Errorf("failed to retrieve genesis from ancient %v", err)
+			} else if !bytes.Equal(kvgenesis, frgenesis) {
 				return nil, fmt.Errorf("genesis mismatch: %#x (leveldb) != %#x (ancients)", kvgenesis, frgenesis)
 			}
 			// Key-value store and freezer belong to the same network. Ensure that they
@@ -150,11 +170,10 @@ func NewDatabaseWithFreezer(db ethdb.KeyValueStore, freezer string, namespace st
 				}
 				// Database contains only older data than the freezer, this happens if the
 				// state was wiped and reinited from an existing freezer.
-			} else {
-				// Key-value store continues where the freezer left off, all is fine. We might
-				// have duplicate blocks (crash after freezer write but before kay-value store
-				// deletion, but that's fine).
 			}
+			// Otherwise, key-value store continues where the freezer left off, all is fine.
+			// We might have duplicate blocks (crash after freezer write but before key-value
+			// store deletion, but that's fine).
 		} else {
 			// If the freezer is empty, ensure nothing was moved yet from the key-value
 			// store, otherwise we'll end up missing data. We check block #1 to decide
@@ -167,9 +186,9 @@ func NewDatabaseWithFreezer(db ethdb.KeyValueStore, freezer string, namespace st
 					return nil, errors.New("ancient chain segments already extracted, please set --datadir.ancient to the correct path")
 				}
 				// Block #1 is still in the database, we're allowed to init a new feezer
-			} else {
-				// The head header is still the genesis, we're allowed to init a new feezer
 			}
+			// Otherwise, the head header is still the genesis, we're allowed to init a new
+			// feezer.
 		}
 	}
 	// Freezer is consistent with the key-value database, permit combining the two
@@ -222,7 +241,7 @@ func NewLevelDBDatabaseWithFreezer(file string, cache int, handles int, freezer
 // InspectDatabase traverses the entire database and checks the size
 // of all different categories of data.
 func InspectDatabase(db ethdb.Database) error {
-	it := db.NewIterator()
+	it := db.NewIterator(nil, nil)
 	defer it.Release()
 
 	var (
@@ -239,7 +258,10 @@ func InspectDatabase(db ethdb.Database) error {
 		numHashPairing  common.StorageSize
 		hashNumPairing  common.StorageSize
 		trieSize        common.StorageSize
+		codeSize        common.StorageSize
 		txlookupSize    common.StorageSize
+		accountSnapSize common.StorageSize
+		storageSnapSize common.StorageSize
 		preimageSize    common.StorageSize
 		bloomBitsSize   common.StorageSize
 		cliqueSnapsSize common.StorageSize
@@ -281,6 +303,10 @@ func InspectDatabase(db ethdb.Database) error {
 			receiptSize += size
 		case bytes.HasPrefix(key, txLookupPrefix) && len(key) == (len(txLookupPrefix)+common.HashLength):
 			txlookupSize += size
+		case bytes.HasPrefix(key, SnapshotAccountPrefix) && len(key) == (len(SnapshotAccountPrefix)+common.HashLength):
+			accountSnapSize += size
+		case bytes.HasPrefix(key, SnapshotStoragePrefix) && len(key) == (len(SnapshotStoragePrefix)+2*common.HashLength):
+			storageSnapSize += size
 		case bytes.HasPrefix(key, preimagePrefix) && len(key) == (len(preimagePrefix)+common.HashLength):
 			preimageSize += size
 		case bytes.HasPrefix(key, bloomBitsPrefix) && len(key) == (len(bloomBitsPrefix)+10+common.HashLength):
@@ -291,6 +317,8 @@ func InspectDatabase(db ethdb.Database) error {
 			chtTrieNodes += size
 		case bytes.HasPrefix(key, []byte("blt-")) && len(key) == 4+common.HashLength:
 			bloomTrieNodes += size
+		case bytes.HasPrefix(key, codePrefix) && len(key) == len(codePrefix)+common.HashLength:
+			codeSize += size
 		case len(key) == common.HashLength:
 			trieSize += size
 		default:
@@ -330,8 +358,11 @@ func InspectDatabase(db ethdb.Database) error {
 		{"Key-Value store", "Block hash->number", hashNumPairing.String()},
 		{"Key-Value store", "Transaction index", txlookupSize.String()},
 		{"Key-Value store", "Bloombit index", bloomBitsSize.String()},
+		{"Key-Value store", "Contract codes", codeSize.String()},
 		{"Key-Value store", "Trie nodes", trieSize.String()},
 		{"Key-Value store", "Trie preimages", preimageSize.String()},
+		{"Key-Value store", "Account snapshot", accountSnapSize.String()},
+		{"Key-Value store", "Storage snapshot", storageSnapSize.String()},
 		{"Key-Value store", "Clique snapshots", cliqueSnapsSize.String()},
 		{"Key-Value store", "Singleton metadata", metadata.String()},
 		{"Ancient store", "Headers", ancientHeaders.String()},
diff --git a/core/rawdb/freezer.go b/core/rawdb/freezer.go
index ce2e879..433290b 100644
--- a/core/rawdb/freezer.go
+++ b/core/rawdb/freezer.go
@@ -22,14 +22,15 @@ import (
 	"math"
 	"os"
 	"path/filepath"
+	"sync"
 	"sync/atomic"
 	"time"
 
 	"github.com/ava-labs/coreth/params"
-	"github.com/ava-labs/go-ethereum/common"
-	"github.com/ava-labs/go-ethereum/ethdb"
-	"github.com/ava-labs/go-ethereum/log"
-	"github.com/ava-labs/go-ethereum/metrics"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/ethdb"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/metrics"
 	"github.com/prometheus/tsdb/fileutil"
 )
 
@@ -69,10 +70,16 @@ type freezer struct {
 	// WARNING: The `frozen` field is accessed atomically. On 32 bit platforms, only
 	// 64-bit aligned fields can be atomic. The struct is guaranteed to be so aligned,
 	// so take advantage of that (https://golang.org/pkg/sync/atomic/#pkg-note-BUG).
-	frozen uint64 // Number of blocks already frozen
+	frozen    uint64 // Number of blocks already frozen
+	threshold uint64 // Number of recent blocks not to freeze (params.FullImmutabilityThreshold apart from tests)
 
 	tables       map[string]*freezerTable // Data tables for storing everything
 	instanceLock fileutil.Releaser        // File-system lock to prevent double opens
+
+	trigger chan chan struct{} // Manual blocking freeze trigger, test determinism
+
+	quit      chan struct{}
+	closeOnce sync.Once
 }
 
 // newFreezer creates a chain freezer that moves ancient chain data into
@@ -80,9 +87,9 @@ type freezer struct {
 func newFreezer(datadir string, namespace string) (*freezer, error) {
 	// Create the initial freezer object
 	var (
-		readMeter   = metrics.NewRegisteredMeter(namespace+"ancient/read", nil)
-		writeMeter  = metrics.NewRegisteredMeter(namespace+"ancient/write", nil)
-		sizeCounter = metrics.NewRegisteredCounter(namespace+"ancient/size", nil)
+		readMeter  = metrics.NewRegisteredMeter(namespace+"ancient/read", nil)
+		writeMeter = metrics.NewRegisteredMeter(namespace+"ancient/write", nil)
+		sizeGauge  = metrics.NewRegisteredGauge(namespace+"ancient/size", nil)
 	)
 	// Ensure the datadir is not a symbolic link if it exists.
 	if info, err := os.Lstat(datadir); !os.IsNotExist(err) {
@@ -99,11 +106,14 @@ func newFreezer(datadir string, namespace string) (*freezer, error) {
 	}
 	// Open all the supported data tables
 	freezer := &freezer{
+		threshold:    params.FullImmutabilityThreshold,
 		tables:       make(map[string]*freezerTable),
 		instanceLock: lock,
+		trigger:      make(chan chan struct{}),
+		quit:         make(chan struct{}),
 	}
 	for name, disableSnappy := range freezerNoSnappy {
-		table, err := newTable(datadir, name, readMeter, writeMeter, sizeCounter, disableSnappy)
+		table, err := newTable(datadir, name, readMeter, writeMeter, sizeGauge, disableSnappy)
 		if err != nil {
 			for _, table := range freezer.tables {
 				table.Close()
@@ -127,14 +137,17 @@ func newFreezer(datadir string, namespace string) (*freezer, error) {
 // Close terminates the chain freezer, unmapping all the data files.
 func (f *freezer) Close() error {
 	var errs []error
-	for _, table := range f.tables {
-		if err := table.Close(); err != nil {
+	f.closeOnce.Do(func() {
+		f.quit <- struct{}{}
+		for _, table := range f.tables {
+			if err := table.Close(); err != nil {
+				errs = append(errs, err)
+			}
+		}
+		if err := f.instanceLock.Release(); err != nil {
 			errs = append(errs, err)
 		}
-	}
-	if err := f.instanceLock.Release(); err != nil {
-		errs = append(errs, err)
-	}
+	})
 	if errs != nil {
 		return fmt.Errorf("%v", errs)
 	}
@@ -218,7 +231,7 @@ func (f *freezer) AppendAncient(number uint64, hash, header, body, receipts, td
 	return nil
 }
 
-// Truncate discards any recent data above the provided threshold number.
+// TruncateAncients discards any recent data above the provided threshold number.
 func (f *freezer) TruncateAncients(items uint64) error {
 	if atomic.LoadUint64(&f.frozen) <= items {
 		return nil
@@ -232,7 +245,7 @@ func (f *freezer) TruncateAncients(items uint64) error {
 	return nil
 }
 
-// sync flushes all data tables to disk.
+// Sync flushes all data tables to disk.
 func (f *freezer) Sync() error {
 	var errs []error
 	for _, table := range f.tables {
@@ -254,48 +267,75 @@ func (f *freezer) Sync() error {
 func (f *freezer) freeze(db ethdb.KeyValueStore) {
 	nfdb := &nofreezedb{KeyValueStore: db}
 
+	var (
+		backoff   bool
+		triggered chan struct{} // Used in tests
+	)
 	for {
+		select {
+		case <-f.quit:
+			log.Info("Freezer shutting down")
+			return
+		default:
+		}
+		if backoff {
+			// If we were doing a manual trigger, notify it
+			if triggered != nil {
+				triggered <- struct{}{}
+				triggered = nil
+			}
+			select {
+			case <-time.NewTimer(freezerRecheckInterval).C:
+				backoff = false
+			case triggered = <-f.trigger:
+				backoff = false
+			case <-f.quit:
+				return
+			}
+		}
 		// Retrieve the freezing threshold.
 		hash := ReadHeadBlockHash(nfdb)
 		if hash == (common.Hash{}) {
 			log.Debug("Current full block hash unavailable") // new chain, empty database
-			time.Sleep(freezerRecheckInterval)
+			backoff = true
 			continue
 		}
 		number := ReadHeaderNumber(nfdb, hash)
+		threshold := atomic.LoadUint64(&f.threshold)
+
 		switch {
 		case number == nil:
 			log.Error("Current full block number unavailable", "hash", hash)
-			time.Sleep(freezerRecheckInterval)
+			backoff = true
 			continue
 
-		case *number < params.ImmutabilityThreshold:
-			log.Debug("Current full block not old enough", "number", *number, "hash", hash, "delay", params.ImmutabilityThreshold)
-			time.Sleep(freezerRecheckInterval)
+		case *number < threshold:
+			log.Debug("Current full block not old enough", "number", *number, "hash", hash, "delay", threshold)
+			backoff = true
 			continue
 
-		case *number-params.ImmutabilityThreshold <= f.frozen:
+		case *number-threshold <= f.frozen:
 			log.Debug("Ancient blocks frozen already", "number", *number, "hash", hash, "frozen", f.frozen)
-			time.Sleep(freezerRecheckInterval)
+			backoff = true
 			continue
 		}
 		head := ReadHeader(nfdb, hash, *number)
 		if head == nil {
 			log.Error("Current full block unavailable", "number", *number, "hash", hash)
-			time.Sleep(freezerRecheckInterval)
+			backoff = true
 			continue
 		}
 		// Seems we have data ready to be frozen, process in usable batches
-		limit := *number - params.ImmutabilityThreshold
+		limit := *number - threshold
 		if limit-f.frozen > freezerBatchLimit {
 			limit = f.frozen + freezerBatchLimit
 		}
 		var (
 			start    = time.Now()
 			first    = f.frozen
-			ancients = make([]common.Hash, 0, limit)
+			ancients = make([]common.Hash, 0, limit-f.frozen)
 		)
-		for f.frozen < limit {
+		for f.frozen <= limit {
 			// Retrieves all the components of the canonical block
 			hash := ReadCanonicalHash(nfdb, f.frozen)
 			if hash == (common.Hash{}) {
@@ -346,11 +386,15 @@ func (f *freezer) freeze(db ethdb.KeyValueStore) {
 			log.Crit("Failed to delete frozen canonical blocks", "err", err)
 		}
 		batch.Reset()
-		// Wipe out side chain also.
+
+		// Wipe out side chains also and track dangling side chians
+		var dangling []common.Hash
 		for number := first; number < f.frozen; number++ {
 			// Always keep the genesis block in active database
 			if number != 0 {
-				for _, hash := range ReadAllHashes(db, number) {
+				dangling = ReadAllHashes(db, number)
+				for _, hash := range dangling {
+					log.Trace("Deleting side chain", "number", number, "hash", hash)
 					DeleteBlock(batch, hash, number)
 				}
 			}
@@ -358,6 +402,41 @@ func (f *freezer) freeze(db ethdb.KeyValueStore) {
 		if err := batch.Write(); err != nil {
 			log.Crit("Failed to delete frozen side blocks", "err", err)
 		}
+		batch.Reset()
+
+		// Step into the future and delete and dangling side chains
+		if f.frozen > 0 {
+			tip := f.frozen
+			for len(dangling) > 0 {
+				drop := make(map[common.Hash]struct{})
+				for _, hash := range dangling {
+					log.Debug("Dangling parent from freezer", "number", tip-1, "hash", hash)
+					drop[hash] = struct{}{}
+				}
+				children := ReadAllHashes(db, tip)
+				for i := 0; i < len(children); i++ {
+					// Dig up the child and ensure it's dangling
+					child := ReadHeader(nfdb, children[i], tip)
+					if child == nil {
+						log.Error("Missing dangling header", "number", tip, "hash", children[i])
+						continue
+					}
+					if _, ok := drop[child.ParentHash]; !ok {
+						children = append(children[:i], children[i+1:]...)
+						i--
+						continue
+					}
+					// Delete all block data associated with the child
+					log.Debug("Deleting dangling block", "number", tip, "hash", children[i], "parent", child.ParentHash)
+					DeleteBlock(batch, children[i], tip)
+				}
+				dangling = children
+				tip++
+			}
+			if err := batch.Write(); err != nil {
+				log.Crit("Failed to delete dangling side blocks", "err", err)
+			}
+		}
 		// Log something friendly for the user
 		context := []interface{}{
 			"blocks", f.frozen - first, "elapsed", common.PrettyDuration(time.Since(start)), "number", f.frozen - 1,
@@ -369,7 +448,7 @@ func (f *freezer) freeze(db ethdb.KeyValueStore) {
 
 		// Avoid database thrashing with tiny writes
 		if f.frozen-first < freezerBatchLimit {
-			time.Sleep(freezerRecheckInterval)
+			backoff = true
 		}
 	}
 }
diff --git a/core/rawdb/freezer_reinit.go b/core/rawdb/freezer_reinit.go
deleted file mode 100644
index 6b9fb79..0000000
--- a/core/rawdb/freezer_reinit.go
+++ /dev/null
@@ -1,127 +0,0 @@
-// Copyright 2019 The go-ethereum Authors
-// This file is part of the go-ethereum library.
-//
-// The go-ethereum library is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Lesser General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// The go-ethereum library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU Lesser General Public License for more details.
-//
-// You should have received a copy of the GNU Lesser General Public License
-// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
-
-package rawdb
-
-import (
-	"errors"
-	"runtime"
-	"sync/atomic"
-	"time"
-
-	"github.com/ava-labs/coreth/core/types"
-	"github.com/ava-labs/go-ethereum/common"
-	"github.com/ava-labs/go-ethereum/common/prque"
-	"github.com/ava-labs/go-ethereum/ethdb"
-	"github.com/ava-labs/go-ethereum/log"
-)
-
-// InitDatabaseFromFreezer reinitializes an empty database from a previous batch
-// of frozen ancient blocks. The method iterates over all the frozen blocks and
-// injects into the database the block hash->number mappings and the transaction
-// lookup entries.
-func InitDatabaseFromFreezer(db ethdb.Database) error {
-	// If we can't access the freezer or it's empty, abort
-	frozen, err := db.Ancients()
-	if err != nil || frozen == 0 {
-		return err
-	}
-	// Blocks previously frozen, iterate over- and hash them concurrently
-	var (
-		number  = ^uint64(0) // -1
-		results = make(chan *types.Block, 4*runtime.NumCPU())
-	)
-	abort := make(chan struct{})
-	defer close(abort)
-
-	for i := 0; i < runtime.NumCPU(); i++ {
-		go func() {
-			for {
-				// Fetch the next task number, terminating if everything's done
-				n := atomic.AddUint64(&number, 1)
-				if n >= frozen {
-					return
-				}
-				// Retrieve the block from the freezer (no need for the hash, we pull by
-				// number from the freezer). If successful, pre-cache the block hash and
-				// the individual transaction hashes for storing into the database.
-				block := ReadBlock(db, common.Hash{}, n)
-				if block != nil {
-					block.Hash()
-					for _, tx := range block.Transactions() {
-						tx.Hash()
-					}
-				}
-				// Feed the block to the aggregator, or abort on interrupt
-				select {
-				case results <- block:
-				case <-abort:
-					return
-				}
-			}
-		}()
-	}
-	// Reassemble the blocks into a contiguous stream and push them out to disk
-	var (
-		queue = prque.New(nil)
-		next  = int64(0)
-
-		batch  = db.NewBatch()
-		start  = time.Now()
-		logged time.Time
-	)
-	for i := uint64(0); i < frozen; i++ {
-		// Retrieve the next result and bail if it's nil
-		block := <-results
-		if block == nil {
-			return errors.New("broken ancient database")
-		}
-		// Push the block into the import queue and process contiguous ranges
-		queue.Push(block, -int64(block.NumberU64()))
-		for !queue.Empty() {
-			// If the next available item is gapped, return
-			if _, priority := queue.Peek(); -priority != next {
-				break
-			}
-			// Next block available, pop it off and index it
-			block = queue.PopItem().(*types.Block)
-			next++
-
-			// Inject hash<->number mapping and txlookup indexes
-			WriteHeaderNumber(batch, block.Hash(), block.NumberU64())
-			WriteTxLookupEntries(batch, block)
-
-			// If enough data was accumulated in memory or we're at the last block, dump to disk
-			if batch.ValueSize() > ethdb.IdealBatchSize || uint64(next) == frozen {
-				if err := batch.Write(); err != nil {
-					return err
-				}
-				batch.Reset()
-			}
-			// If we've spent too much time already, notify the user of what we're doing
-			if time.Since(logged) > 8*time.Second {
-				log.Info("Initializing chain from ancient data", "number", block.Number(), "hash", block.Hash(), "total", frozen-1, "elapsed", common.PrettyDuration(time.Since(start)))
-				logged = time.Now()
-			}
-		}
-	}
-	hash := ReadCanonicalHash(db, frozen-1)
-	WriteHeadHeaderHash(db, hash)
-	WriteHeadFastBlockHash(db, hash)
-
-	log.Info("Initialized chain from ancient data", "number", frozen-1, "hash", hash, "elapsed", common.PrettyDuration(time.Since(start)))
-	return nil
-}
diff --git a/core/rawdb/freezer_table.go b/core/rawdb/freezer_table.go
index fc72669..b9d8a27 100644
--- a/core/rawdb/freezer_table.go
+++ b/core/rawdb/freezer_table.go
@@ -26,9 +26,9 @@ import (
 	"sync"
 	"sync/atomic"
 
-	"github.com/ava-labs/go-ethereum/common"
-	"github.com/ava-labs/go-ethereum/log"
-	"github.com/ava-labs/go-ethereum/metrics"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/metrics"
 	"github.com/golang/snappy"
 )
 
@@ -94,18 +94,18 @@ type freezerTable struct {
 	// to count how many historic items have gone missing.
 	itemOffset uint32 // Offset (number of discarded items)
 
-	headBytes   uint32          // Number of bytes written to the head file
-	readMeter   metrics.Meter   // Meter for measuring the effective amount of data read
-	writeMeter  metrics.Meter   // Meter for measuring the effective amount of data written
-	sizeCounter metrics.Counter // Counter for tracking the combined size of all freezer tables
+	headBytes  uint32        // Number of bytes written to the head file
+	readMeter  metrics.Meter // Meter for measuring the effective amount of data read
+	writeMeter metrics.Meter // Meter for measuring the effective amount of data written
+	sizeGauge  metrics.Gauge // Gauge for tracking the combined size of all freezer tables
 
 	logger log.Logger   // Logger with database path and table name ambedded
 	lock   sync.RWMutex // Mutex protecting the data file descriptors
 }
 
 // newTable opens a freezer table with default settings - 2G files
-func newTable(path string, name string, readMeter metrics.Meter, writeMeter metrics.Meter, sizeCounter metrics.Counter, disableSnappy bool) (*freezerTable, error) {
-	return newCustomTable(path, name, readMeter, writeMeter, sizeCounter, 2*1000*1000*1000, disableSnappy)
+func newTable(path string, name string, readMeter metrics.Meter, writeMeter metrics.Meter, sizeGauge metrics.Gauge, disableSnappy bool) (*freezerTable, error) {
+	return newCustomTable(path, name, readMeter, writeMeter, sizeGauge, 2*1000*1000*1000, disableSnappy)
 }
 
 // openFreezerFileForAppend opens a freezer table file and seeks to the end
@@ -149,7 +149,7 @@ func truncateFreezerFile(file *os.File, size int64) error {
 // newCustomTable opens a freezer table, creating the data and index files if they are
 // non existent. Both files are truncated to the shortest common length to ensure
 // they don't go out of sync.
-func newCustomTable(path string, name string, readMeter metrics.Meter, writeMeter metrics.Meter, sizeCounter metrics.Counter, maxFilesize uint32, noCompression bool) (*freezerTable, error) {
+func newCustomTable(path string, name string, readMeter metrics.Meter, writeMeter metrics.Meter, sizeGauge metrics.Gauge, maxFilesize uint32, noCompression bool) (*freezerTable, error) {
 	// Ensure the containing directory exists and open the indexEntry file
 	if err := os.MkdirAll(path, 0755); err != nil {
 		return nil, err
@@ -172,7 +172,7 @@ func newCustomTable(path string, name string, readMeter metrics.Meter, writeMete
 		files:         make(map[uint32]*os.File),
 		readMeter:     readMeter,
 		writeMeter:    writeMeter,
-		sizeCounter:   sizeCounter,
+		sizeGauge:     sizeGauge,
 		name:          name,
 		path:          path,
 		logger:        log.New("database", path, "table", name),
@@ -189,7 +189,7 @@ func newCustomTable(path string, name string, readMeter metrics.Meter, writeMete
 		tab.Close()
 		return nil, err
 	}
-	tab.sizeCounter.Inc(int64(size))
+	tab.sizeGauge.Inc(int64(size))
 
 	return tab, nil
 }
@@ -232,8 +232,8 @@ func (t *freezerTable) repair() error {
 	t.index.ReadAt(buffer, 0)
 	firstIndex.unmarshalBinary(buffer)
 
-	t.tailId = firstIndex.offset
-	t.itemOffset = firstIndex.filenum
+	t.tailId = firstIndex.filenum
+	t.itemOffset = firstIndex.offset
 
 	t.index.ReadAt(buffer, offsetsSize-indexEntrySize)
 	lastIndex.unmarshalBinary(buffer)
@@ -330,7 +330,8 @@ func (t *freezerTable) truncate(items uint64) error {
 	defer t.lock.Unlock()
 
 	// If our item count is correct, don't do anything
-	if atomic.LoadUint64(&t.items) <= items {
+	existing := atomic.LoadUint64(&t.items)
+	if existing <= items {
 		return nil
 	}
 	// We need to truncate, save the old size for metrics tracking
@@ -339,7 +340,11 @@ func (t *freezerTable) truncate(items uint64) error {
 		return err
 	}
 	// Something's out of sync, truncate the table's offset index
-	t.logger.Warn("Truncating freezer table", "items", t.items, "limit", items)
+	log := t.logger.Debug
+	if existing > items+1 {
+		log = t.logger.Warn // Only loud warn if we delete multiple items
+	}
+	log("Truncating freezer table", "items", existing, "limit", items)
 	if err := truncateFreezerFile(t.index, int64(items+1)*indexEntrySize); err != nil {
 		return err
 	}
@@ -378,7 +383,7 @@ func (t *freezerTable) truncate(items uint64) error {
 	if err != nil {
 		return err
 	}
-	t.sizeCounter.Dec(int64(oldSize - newSize))
+	t.sizeGauge.Dec(int64(oldSize - newSize))
 
 	return nil
 }
@@ -510,7 +515,7 @@ func (t *freezerTable) Append(item uint64, blob []byte) error {
 	t.index.Write(idx.marshallBinary())
 
 	t.writeMeter.Mark(int64(bLen + indexEntrySize))
-	t.sizeCounter.Inc(int64(bLen + indexEntrySize))
+	t.sizeGauge.Inc(int64(bLen + indexEntrySize))
 
 	atomic.AddUint64(&t.items, 1)
 	return nil
@@ -519,16 +524,27 @@ func (t *freezerTable) Append(item uint64, blob []byte) error {
 // getBounds returns the indexes for the item
 // returns start, end, filenumber and error
 func (t *freezerTable) getBounds(item uint64) (uint32, uint32, uint32, error) {
-	var startIdx, endIdx indexEntry
 	buffer := make([]byte, indexEntrySize)
-	if _, err := t.index.ReadAt(buffer, int64(item*indexEntrySize)); err != nil {
-		return 0, 0, 0, err
-	}
-	startIdx.unmarshalBinary(buffer)
+	var startIdx, endIdx indexEntry
+	// Read second index
 	if _, err := t.index.ReadAt(buffer, int64((item+1)*indexEntrySize)); err != nil {
 		return 0, 0, 0, err
 	}
 	endIdx.unmarshalBinary(buffer)
+	// Read first index (unless it's the very first item)
+	if item != 0 {
+		if _, err := t.index.ReadAt(buffer, int64(item*indexEntrySize)); err != nil {
+			return 0, 0, 0, err
+		}
+		startIdx.unmarshalBinary(buffer)
+	} else {
+		// Special case if we're reading the first item in the freezer. We assume that
+		// the first item always start from zero(regarding the deletion, we
+		// only support deletion by files, so that the assumption is held).
+		// This means we can use the first item metadata to carry information about
+		// the 'global' offset, for the deletion-case
+		return 0, endIdx.offset, endIdx.filenum, nil
+	}
 	if startIdx.filenum != endIdx.filenum {
 		// If a piece of data 'crosses' a data-file,
 		// it's actually in one piece on the second data-file.
@@ -541,20 +557,22 @@ func (t *freezerTable) getBounds(item uint64) (uint32, uint32, uint32, error) {
 // Retrieve looks up the data offset of an item with the given number and retrieves
 // the raw binary blob from the data file.
 func (t *freezerTable) Retrieve(item uint64) ([]byte, error) {
+	t.lock.RLock()
 	// Ensure the table and the item is accessible
 	if t.index == nil || t.head == nil {
+		t.lock.RUnlock()
 		return nil, errClosed
 	}
 	if atomic.LoadUint64(&t.items) <= item {
+		t.lock.RUnlock()
 		return nil, errOutOfBounds
 	}
 	// Ensure the item was not deleted from the tail either
-	offset := atomic.LoadUint32(&t.itemOffset)
-	if uint64(offset) > item {
+	if uint64(t.itemOffset) > item {
+		t.lock.RUnlock()
 		return nil, errOutOfBounds
 	}
-	t.lock.RLock()
-	startOffset, endOffset, filenum, err := t.getBounds(item - uint64(offset))
+	startOffset, endOffset, filenum, err := t.getBounds(item - uint64(t.itemOffset))
 	if err != nil {
 		t.lock.RUnlock()
 		return nil, err
diff --git a/core/rawdb/schema.go b/core/rawdb/schema.go
index 51d1f66..e2b093a 100644
--- a/core/rawdb/schema.go
+++ b/core/rawdb/schema.go
@@ -18,10 +18,11 @@
 package rawdb
 
 import (
+	"bytes"
 	"encoding/binary"
 
-	"github.com/ava-labs/go-ethereum/common"
-	"github.com/ava-labs/go-ethereum/metrics"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/metrics"
 )
 
 // The fields below define the low level database schema prefixing.
@@ -38,9 +39,24 @@ var (
 	// headFastBlockKey tracks the latest known incomplete block's hash during fast sync.
 	headFastBlockKey = []byte("LastFast")
 
+	// lastPivotKey tracks the last pivot block used by fast sync (to reenable on sethead).
+	lastPivotKey = []byte("LastPivot")
+
 	// fastTrieProgressKey tracks the number of trie entries imported during fast sync.
 	fastTrieProgressKey = []byte("TrieSync")
 
+	// snapshotRootKey tracks the hash of the last snapshot.
+	snapshotRootKey = []byte("SnapshotRoot")
+
+	// snapshotJournalKey tracks the in-memory diff layers across restarts.
+	snapshotJournalKey = []byte("SnapshotJournal")
+
+	// txIndexTailKey tracks the oldest block whose transactions have been indexed.
+	txIndexTailKey = []byte("TransactionIndexTail")
+
+	// fastTxLookupLimitKey tracks the transaction lookup limit during fast sync.
+	fastTxLookupLimitKey = []byte("FastTransactionLookupLimit")
+
 	// Data item prefixes (use single byte to avoid mixing data types, avoid `i`, used for indexes).
 	headerPrefix       = []byte("h") // headerPrefix + num (uint64 big endian) + hash -> header
 	headerTDSuffix     = []byte("t") // headerPrefix + num (uint64 big endian) + hash + headerTDSuffix -> td
@@ -50,8 +66,11 @@ var (
 	blockBodyPrefix     = []byte("b") // blockBodyPrefix + num (uint64 big endian) + hash -> block body
 	blockReceiptsPrefix = []byte("r") // blockReceiptsPrefix + num (uint64 big endian) + hash -> block receipts
 
-	txLookupPrefix  = []byte("l") // txLookupPrefix + hash -> transaction/receipt lookup metadata
-	bloomBitsPrefix = []byte("B") // bloomBitsPrefix + bit (uint16 big endian) + section (uint64 big endian) + hash -> bloom bits
+	txLookupPrefix        = []byte("l") // txLookupPrefix + hash -> transaction/receipt lookup metadata
+	bloomBitsPrefix       = []byte("B") // bloomBitsPrefix + bit (uint16 big endian) + section (uint64 big endian) + hash -> bloom bits
+	SnapshotAccountPrefix = []byte("a") // SnapshotAccountPrefix + account hash -> account trie value
+	SnapshotStoragePrefix = []byte("o") // SnapshotStoragePrefix + account hash + storage hash -> storage trie value
+	codePrefix            = []byte("c") // codePrefix + code hash -> account code
 
 	preimagePrefix = []byte("secure-key-")      // preimagePrefix + hash -> preimage
 	configPrefix   = []byte("ethereum-config-") // config prefix for the db
@@ -145,6 +164,21 @@ func txLookupKey(hash common.Hash) []byte {
 	return append(txLookupPrefix, hash.Bytes()...)
 }
 
+// accountSnapshotKey = SnapshotAccountPrefix + hash
+func accountSnapshotKey(hash common.Hash) []byte {
+	return append(SnapshotAccountPrefix, hash.Bytes()...)
+}
+
+// storageSnapshotKey = SnapshotStoragePrefix + account hash + storage hash
+func storageSnapshotKey(accountHash, storageHash common.Hash) []byte {
+	return append(append(SnapshotStoragePrefix, accountHash.Bytes()...), storageHash.Bytes()...)
+}
+
+// storageSnapshotsKey = SnapshotStoragePrefix + account hash + storage hash
+func storageSnapshotsKey(accountHash common.Hash) []byte {
+	return append(SnapshotStoragePrefix, accountHash.Bytes()...)
+}
+
 // bloomBitsKey = bloomBitsPrefix + bit (uint16 big endian) + section (uint64 big endian) + hash
 func bloomBitsKey(bit uint, section uint64, hash common.Hash) []byte {
 	key := append(append(bloomBitsPrefix, make([]byte, 10)...), hash.Bytes()...)
@@ -160,6 +194,20 @@ func preimageKey(hash common.Hash) []byte {
 	return append(preimagePrefix, hash.Bytes()...)
 }
 
+// codeKey = codePrefix + hash
+func codeKey(hash common.Hash) []byte {
+	return append(codePrefix, hash.Bytes()...)
+}
+
+// IsCodeKey reports whether the given byte slice is the key of contract code,
+// if so return the raw code hash as well.
+func IsCodeKey(key []byte) (bool, []byte) {
+	if bytes.HasPrefix(key, codePrefix) && len(key) == common.HashLength+len(codePrefix) {
+		return true, key[len(codePrefix):]
+	}
+	return false, nil
+}
+
 // configKey = configPrefix + hash
 func configKey(hash common.Hash) []byte {
 	return append(configPrefix, hash.Bytes()...)
diff --git a/core/rawdb/table.go b/core/rawdb/table.go
index f9078e8..323ef62 100644
--- a/core/rawdb/table.go
+++ b/core/rawdb/table.go
@@ -17,7 +17,7 @@
 package rawdb
 
 import (
-	"github.com/ava-labs/go-ethereum/ethdb"
+	"github.com/ethereum/go-ethereum/ethdb"
 )
 
 // table is a wrapper around a database that prefixes each key access with a pre-
@@ -103,23 +103,16 @@ func (t *table) Delete(key []byte) error {
 	return t.db.Delete(append([]byte(t.prefix), key...))
 }
 
-// NewIterator creates a binary-alphabetical iterator over the entire keyspace
-// contained within the database.
-func (t *table) NewIterator() ethdb.Iterator {
-	return t.NewIteratorWithPrefix(nil)
-}
-
-// NewIteratorWithStart creates a binary-alphabetical iterator over a subset of
-// database content starting at a particular initial key (or after, if it does
-// not exist).
-func (t *table) NewIteratorWithStart(start []byte) ethdb.Iterator {
-	return t.db.NewIteratorWithStart(start)
-}
-
-// NewIteratorWithPrefix creates a binary-alphabetical iterator over a subset
-// of database content with a particular key prefix.
-func (t *table) NewIteratorWithPrefix(prefix []byte) ethdb.Iterator {
-	return t.db.NewIteratorWithPrefix(append([]byte(t.prefix), prefix...))
+// NewIterator creates a binary-alphabetical iterator over a subset
+// of database content with a particular key prefix, starting at a particular
+// initial key (or after, if it does not exist).
+func (t *table) NewIterator(prefix []byte, start []byte) ethdb.Iterator {
+	innerPrefix := append([]byte(t.prefix), prefix...)
+	iter := t.db.NewIterator(innerPrefix, start)
+	return &tableIterator{
+		iter:   iter,
+		prefix: t.prefix,
+	}
 }
 
 // Stat returns a particular internal stat of the database.
@@ -198,7 +191,69 @@ func (b *tableBatch) Reset() {
 	b.batch.Reset()
 }
 
+// tableReplayer is a wrapper around a batch replayer which truncates
+// the added prefix.
+type tableReplayer struct {
+	w      ethdb.KeyValueWriter
+	prefix string
+}
+
+// Put implements the interface KeyValueWriter.
+func (r *tableReplayer) Put(key []byte, value []byte) error {
+	trimmed := key[len(r.prefix):]
+	return r.w.Put(trimmed, value)
+}
+
+// Delete implements the interface KeyValueWriter.
+func (r *tableReplayer) Delete(key []byte) error {
+	trimmed := key[len(r.prefix):]
+	return r.w.Delete(trimmed)
+}
+
 // Replay replays the batch contents.
 func (b *tableBatch) Replay(w ethdb.KeyValueWriter) error {
-	return b.batch.Replay(w)
+	return b.batch.Replay(&tableReplayer{w: w, prefix: b.prefix})
+}
+
+// tableIterator is a wrapper around a database iterator that prefixes each key access
+// with a pre-configured string.
+type tableIterator struct {
+	iter   ethdb.Iterator
+	prefix string
+}
+
+// Next moves the iterator to the next key/value pair. It returns whether the
+// iterator is exhausted.
+func (iter *tableIterator) Next() bool {
+	return iter.iter.Next()
+}
+
+// Error returns any accumulated error. Exhausting all the key/value pairs
+// is not considered to be an error.
+func (iter *tableIterator) Error() error {
+	return iter.iter.Error()
+}
+
+// Key returns the key of the current key/value pair, or nil if done. The caller
+// should not modify the contents of the returned slice, and its contents may
+// change on the next call to Next.
+func (iter *tableIterator) Key() []byte {
+	key := iter.iter.Key()
+	if key == nil {
+		return nil
+	}
+	return key[len(iter.prefix):]
+}
+
+// Value returns the value of the current key/value pair, or nil if done. The
+// caller should not modify the contents of the returned slice, and its contents
+// may change on the next call to Next.
+func (iter *tableIterator) Value() []byte {
+	return iter.iter.Value()
+}
+
+// Release releases associated resources. Release should always succeed and can
+// be called multiple times without causing error.
+func (iter *tableIterator) Release() {
+	iter.iter.Release()
 }
-- 
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