trie: remove the global node cache

Now that we keep more nodes loaded, the cache is no longer required.

build/update-license.go

@@ -49,7 +49,6 @@ var (
 		// don't relicense vendored sources
 		"crypto/sha3/", "crypto/ecies/", "logger/glog/",
 		"crypto/secp256k1/curve.go",
-		"trie/arc.go",
 		// don't license generated files
 		"contracts/chequebook/contract/",
 		"contracts/ens/contract/",

core/state/sync_test.go

@@ -62,9 +62,6 @@ func makeTestState() (ethdb.Database, common.Hash, []*testAccount) {
 	}
 	root, _ := state.Commit()
 
-	// Remove any potentially cached data from the test state creation
-	trie.ClearGlobalCache()
-
 	// Return the generated state
 	return db, root, accounts
 }
@@ -72,9 +69,6 @@ func makeTestState() (ethdb.Database, common.Hash, []*testAccount) {
 // checkStateAccounts cross references a reconstructed state with an expected
 // account array.
 func checkStateAccounts(t *testing.T, db ethdb.Database, root common.Hash, accounts []*testAccount) {
-	// Remove any potentially cached data from the state synchronisation
-	trie.ClearGlobalCache()
-
 	// Check root availability and state contents
 	state, err := New(root, db)
 	if err != nil {
@@ -98,9 +92,6 @@ func checkStateAccounts(t *testing.T, db ethdb.Database, root common.Hash, accou
 
 // checkStateConsistency checks that all nodes in a state trie are indeed present.
 func checkStateConsistency(db ethdb.Database, root common.Hash) error {
-	// Remove any potentially cached data from the test state creation or previous checks
-	trie.ClearGlobalCache()
-
 	// Create and iterate a state trie rooted in a sub-node
 	if _, err := db.Get(root.Bytes()); err != nil {
 		return nil // Consider a non existent state consistent

light/state_test.go

@@ -42,7 +42,6 @@ func (odr *testOdr) Retrieve(ctx context.Context, req OdrRequest) error {
 	case *TrieRequest:
 		t, _ := trie.New(req.root, odr.sdb)
 		req.proof = t.Prove(req.key)
-		trie.ClearGlobalCache()
 	case *NodeDataRequest:
 		req.data, _ = odr.sdb.Get(req.hash[:])
 	}
@@ -75,7 +74,6 @@ func TestLightStateOdr(t *testing.T) {
 	odr := &testOdr{sdb: sdb, ldb: ldb}
 	ls := NewLightState(root, odr)
 	ctx := context.Background()
-	trie.ClearGlobalCache()
 
 	for i := byte(0); i < 100; i++ {
 		addr := common.Address{i}
@@ -160,7 +158,6 @@ func TestLightStateSetCopy(t *testing.T) {
 	odr := &testOdr{sdb: sdb, ldb: ldb}
 	ls := NewLightState(root, odr)
 	ctx := context.Background()
-	trie.ClearGlobalCache()
 
 	for i := byte(0); i < 100; i++ {
 		addr := common.Address{i}
@@ -237,7 +234,6 @@ func TestLightStateDelete(t *testing.T) {
 	odr := &testOdr{sdb: sdb, ldb: ldb}
 	ls := NewLightState(root, odr)
 	ctx := context.Background()
-	trie.ClearGlobalCache()
 
 	addr := common.Address{42}
 

trie/arc.go

@@ -1,206 +0,0 @@
-// Copyright (c) 2015 Hans Alexander Gugel <alexander.gugel@gmail.com>
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy
-// of this software and associated documentation files (the "Software"), to deal
-// in the Software without restriction, including without limitation the rights
-// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-// copies of the Software, and to permit persons to whom the Software is
-// furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in all
-// copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-// SOFTWARE.
-
-// This file contains a modified version of package arc from
-// https://github.com/alexanderGugel/arc
-//
-// It implements the ARC (Adaptive Replacement Cache) algorithm as detailed in
-// https://www.usenix.org/legacy/event/fast03/tech/full_papers/megiddo/megiddo.pdf
-
-package trie
-
-import (
-	"container/list"
-	"sync"
-)
-
-type arc struct {
-	p     int
-	c     int
-	t1    *list.List
-	b1    *list.List
-	t2    *list.List
-	b2    *list.List
-	cache map[string]*entry
-	mutex sync.Mutex
-}
-
-type entry struct {
-	key   hashNode
-	value node
-	ll    *list.List
-	el    *list.Element
-}
-
-// newARC returns a new Adaptive Replacement Cache with the
-// given capacity.
-func newARC(c int) *arc {
-	return &arc{
-		c:     c,
-		t1:    list.New(),
-		b1:    list.New(),
-		t2:    list.New(),
-		b2:    list.New(),
-		cache: make(map[string]*entry, c),
-	}
-}
-
-// Clear clears the cache
-func (a *arc) Clear() {
-	a.mutex.Lock()
-	defer a.mutex.Unlock()
-	a.p = 0
-	a.t1 = list.New()
-	a.b1 = list.New()
-	a.t2 = list.New()
-	a.b2 = list.New()
-	a.cache = make(map[string]*entry, a.c)
-}
-
-// Put inserts a new key-value pair into the cache.
-// This optimizes future access to this entry (side effect).
-func (a *arc) Put(key hashNode, value node) bool {
-	a.mutex.Lock()
-	defer a.mutex.Unlock()
-	ent, ok := a.cache[string(key)]
-	if ok != true {
-		ent = &entry{key: key, value: value}
-		a.req(ent)
-		a.cache[string(key)] = ent
-	} else {
-		ent.value = value
-		a.req(ent)
-	}
-	return ok
-}
-
-// Get retrieves a previously via Set inserted entry.
-// This optimizes future access to this entry (side effect).
-func (a *arc) Get(key hashNode) (value node, ok bool) {
-	a.mutex.Lock()
-	defer a.mutex.Unlock()
-	ent, ok := a.cache[string(key)]
-	if ok {
-		a.req(ent)
-		return ent.value, ent.value != nil
-	}
-	return nil, false
-}
-
-func (a *arc) req(ent *entry) {
-	if ent.ll == a.t1 || ent.ll == a.t2 {
-		// Case I
-		ent.setMRU(a.t2)
-	} else if ent.ll == a.b1 {
-		// Case II
-		// Cache Miss in t1 and t2
-
-		// Adaptation
-		var d int
-		if a.b1.Len() >= a.b2.Len() {
-			d = 1
-		} else {
-			d = a.b2.Len() / a.b1.Len()
-		}
-		a.p = a.p + d
-		if a.p > a.c {
-			a.p = a.c
-		}
-
-		a.replace(ent)
-		ent.setMRU(a.t2)
-	} else if ent.ll == a.b2 {
-		// Case III
-		// Cache Miss in t1 and t2
-
-		// Adaptation
-		var d int
-		if a.b2.Len() >= a.b1.Len() {
-			d = 1
-		} else {
-			d = a.b1.Len() / a.b2.Len()
-		}
-		a.p = a.p - d
-		if a.p < 0 {
-			a.p = 0
-		}
-
-		a.replace(ent)
-		ent.setMRU(a.t2)
-	} else if ent.ll == nil {
-		// Case IV
-
-		if a.t1.Len()+a.b1.Len() == a.c {
-			// Case A
-			if a.t1.Len() < a.c {
-				a.delLRU(a.b1)
-				a.replace(ent)
-			} else {
-				a.delLRU(a.t1)
-			}
-		} else if a.t1.Len()+a.b1.Len() < a.c {
-			// Case B
-			if a.t1.Len()+a.t2.Len()+a.b1.Len()+a.b2.Len() >= a.c {
-				if a.t1.Len()+a.t2.Len()+a.b1.Len()+a.b2.Len() == 2*a.c {
-					a.delLRU(a.b2)
-				}
-				a.replace(ent)
-			}
-		}
-
-		ent.setMRU(a.t1)
-	}
-}
-
-func (a *arc) delLRU(list *list.List) {
-	lru := list.Back()
-	list.Remove(lru)
-	delete(a.cache, string(lru.Value.(*entry).key))
-}
-
-func (a *arc) replace(ent *entry) {
-	if a.t1.Len() > 0 && ((a.t1.Len() > a.p) || (ent.ll == a.b2 && a.t1.Len() == a.p)) {
-		lru := a.t1.Back().Value.(*entry)
-		lru.value = nil
-		lru.setMRU(a.b1)
-	} else {
-		lru := a.t2.Back().Value.(*entry)
-		lru.value = nil
-		lru.setMRU(a.b2)
-	}
-}
-
-func (e *entry) setLRU(list *list.List) {
-	e.detach()
-	e.ll = list
-	e.el = e.ll.PushBack(e)
-}
-
-func (e *entry) setMRU(list *list.List) {
-	e.detach()
-	e.ll = list
-	e.el = e.ll.PushFront(e)
-}
-
-func (e *entry) detach() {
-	if e.ll != nil {
-		e.ll.Remove(e.el)
-	}
-}

trie/sync_test.go

@@ -51,9 +51,6 @@ func makeTestTrie() (ethdb.Database, *Trie, map[string][]byte) {
 	}
 	trie.Commit()
 
-	// Remove any potentially cached data from the test trie creation
-	globalCache.Clear()
-
 	// Return the generated trie
 	return db, trie, content
 }
@@ -61,9 +58,6 @@ func makeTestTrie() (ethdb.Database, *Trie, map[string][]byte) {
 // checkTrieContents cross references a reconstructed trie with an expected data
 // content map.
 func checkTrieContents(t *testing.T, db Database, root []byte, content map[string][]byte) {
-	// Remove any potentially cached data from the trie synchronisation
-	globalCache.Clear()
-
 	// Check root availability and trie contents
 	trie, err := New(common.BytesToHash(root), db)
 	if err != nil {
@@ -81,9 +75,6 @@ func checkTrieContents(t *testing.T, db Database, root []byte, content map[strin
 
 // checkTrieConsistency checks that all nodes in a trie are indeed present.
 func checkTrieConsistency(db Database, root common.Hash) error {
-	// Remove any potentially cached data from the test trie creation or previous checks
-	globalCache.Clear()
-
 	// Create and iterate a trie rooted in a subnode
 	trie, err := New(root, db)
 	if err != nil {

trie/trie.go

@@ -30,12 +30,7 @@ import (
 	"github.com/ethereum/go-ethereum/rlp"
 )
 
-const defaultCacheCapacity = 800
-
 var (
-	// The global cache stores decoded trie nodes by hash as they get loaded.
-	globalCache = newARC(defaultCacheCapacity)
-
 	// This is the known root hash of an empty trie.
 	emptyRoot = common.HexToHash("56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421")
 
@@ -43,11 +38,6 @@ var (
 	emptyState = crypto.Keccak256Hash(nil)
 )
 
-// ClearGlobalCache clears the global trie cache
-func ClearGlobalCache() {
-	globalCache.Clear()
-}
-
 // Database must be implemented by backing stores for the trie.
 type Database interface {
 	DatabaseWriter
@@ -427,9 +417,6 @@ func (t *Trie) resolve(n node, prefix, suffix []byte) (node, error) {
 }
 
 func (t *Trie) resolveHash(n hashNode, prefix, suffix []byte) (node, error) {
-	if v, ok := globalCache.Get(n); ok {
-		return v, nil
-	}
 	enc, err := t.db.Get(n)
 	if err != nil || enc == nil {
 		return nil, &MissingNodeError{
@@ -441,9 +428,6 @@ func (t *Trie) resolveHash(n hashNode, prefix, suffix []byte) (node, error) {
 		}
 	}
 	dec := mustDecodeNode(n, enc)
-	if dec != nil {
-		globalCache.Put(n, dec)
-	}
 	return dec, nil
 }
 

trie/trie_test.go

@@ -76,8 +76,6 @@ func TestMissingNode(t *testing.T) {
 	updateString(trie, "123456", "asdfasdfasdfasdfasdfasdfasdfasdf")
 	root, _ := trie.Commit()
 
-	ClearGlobalCache()
-
 	trie, _ = New(root, db)
 	_, err := trie.TryGet([]byte("120000"))
 	if err != nil {
@@ -109,7 +107,6 @@ func TestMissingNode(t *testing.T) {
 	}
 
 	db.Delete(common.FromHex("e1d943cc8f061a0c0b98162830b970395ac9315654824bf21b73b891365262f9"))
-	ClearGlobalCache()
 
 	trie, _ = New(root, db)
 	_, err = trie.TryGet([]byte("120000"))