update disk root more frequently

core/blockchain.go

@@ -140,6 +140,9 @@ type CacheConfig struct {
 	StateHistory        uint64        // Number of blocks from head whose state histories are reserved.
 	StateScheme         string        // Scheme used to store ethereum states and merkle tree nodes on top
 
+	EnableDiskRootInterval bool          // Enable update disk root when time threshold is reached. Disabled by default
+	DiskRootThreshold      time.Duration // Time threshold after which to flush the layers to disk
+
 	SnapshotNoBuild bool // Whether the background generation is allowed
 	SnapshotWait    bool // Wait for snapshot construction on startup. TODO(karalabe): This is a dirty hack for testing, nuke it
 }
@@ -168,12 +171,14 @@ func (c *CacheConfig) triedbConfig(isVerkle bool) *triedb.Config {
 // defaultCacheConfig are the default caching values if none are specified by the
 // user (also used during testing).
 var defaultCacheConfig = &CacheConfig{
-	TrieCleanLimit: 256,
-	TrieDirtyLimit: 256,
-	TrieTimeLimit:  5 * time.Minute,
-	SnapshotLimit:  256,
-	SnapshotWait:   true,
-	StateScheme:    rawdb.HashScheme,
+	TrieCleanLimit:         256,
+	TrieDirtyLimit:         256,
+	TrieTimeLimit:          5 * time.Minute,
+	SnapshotLimit:          256,
+	SnapshotWait:           true,
+	StateScheme:            rawdb.HashScheme,
+	EnableDiskRootInterval: false,
+	DiskRootThreshold:      60 * time.Minute,
 }
 
 // DefaultCacheConfigWithScheme returns a deep copied default cache config with
@@ -441,10 +446,12 @@ func NewBlockChain(db ethdb.Database, cacheConfig *CacheConfig, genesis *Genesis
 			recover = true
 		}
 		snapconfig := snapshot.Config{
-			CacheSize:  bc.cacheConfig.SnapshotLimit,
-			Recovery:   recover,
-			NoBuild:    bc.cacheConfig.SnapshotNoBuild,
-			AsyncBuild: !bc.cacheConfig.SnapshotWait,
+			CacheSize:              bc.cacheConfig.SnapshotLimit,
+			Recovery:               recover,
+			NoBuild:                bc.cacheConfig.SnapshotNoBuild,
+			AsyncBuild:             !bc.cacheConfig.SnapshotWait,
+			EnableDiskRootInterval: bc.cacheConfig.EnableDiskRootInterval,
+			DiskRootThreshold:      bc.cacheConfig.DiskRootThreshold,
 		}
 		bc.snaps, _ = snapshot.New(snapconfig, bc.db, bc.triedb, head.Root)
 	}

core/state/snapshot/difflayer.go

@@ -76,6 +76,9 @@ var (
 	bloomDestructHasherOffset = 0
 	bloomAccountHasherOffset  = 0
 	bloomStorageHasherOffset  = 0
+
+	// Setting a minimum to prevent very low input from user
+	minTimeThreshold = 1 * time.Minute
 )
 
 func init() {

core/state/snapshot/snapshot.go

@@ -22,6 +22,7 @@ import (
 	"errors"
 	"fmt"
 	"sync"
+	"time"
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/rawdb"
@@ -150,10 +151,12 @@ type snapshot interface {
 
 // Config includes the configurations for snapshots.
 type Config struct {
-	CacheSize  int  // Megabytes permitted to use for read caches
-	Recovery   bool // Indicator that the snapshots is in the recovery mode
-	NoBuild    bool // Indicator that the snapshots generation is disallowed
-	AsyncBuild bool // The snapshot generation is allowed to be constructed asynchronously
+	CacheSize              int           // Megabytes permitted to use for read caches
+	Recovery               bool          // Indicator that the snapshots is in the recovery mode
+	NoBuild                bool          // Indicator that the snapshots generation is disallowed
+	AsyncBuild             bool          // The snapshot generation is allowed to be constructed asynchronously
+	EnableDiskRootInterval bool          // The disk root is allowed to update after a time threshold
+	DiskRootThreshold      time.Duration // The threshold to update disk root
 }
 
 // Tree is an Ethereum state snapshot tree. It consists of one persistent base
@@ -166,11 +169,12 @@ type Config struct {
 // storage data to avoid expensive multi-level trie lookups; and to allow sorted,
 // cheap iteration of the account/storage tries for sync aid.
 type Tree struct {
-	config Config                   // Snapshots configurations
-	diskdb ethdb.KeyValueStore      // Persistent database to store the snapshot
-	triedb *triedb.Database         // In-memory cache to access the trie through
-	layers map[common.Hash]snapshot // Collection of all known layers
-	lock   sync.RWMutex
+	config   Config                   // Snapshots configurations
+	diskdb   ethdb.KeyValueStore      // Persistent database to store the snapshot
+	triedb   *triedb.Database         // In-memory cache to access the trie through
+	layers   map[common.Hash]snapshot // Collection of all known layers
+	lock     sync.RWMutex
+	baseTime time.Time // Reference to calculate the time threshold
 
 	// Test hooks
 	onFlatten func() // Hook invoked when the bottom most diff layers are flattened
@@ -195,11 +199,18 @@ type Tree struct {
 func New(config Config, diskdb ethdb.KeyValueStore, triedb *triedb.Database, root common.Hash) (*Tree, error) {
 	// Create a new, empty snapshot tree
 	snap := &Tree{
-		config: config,
-		diskdb: diskdb,
-		triedb: triedb,
-		layers: make(map[common.Hash]snapshot),
+		config:   config,
+		diskdb:   diskdb,
+		triedb:   triedb,
+		layers:   make(map[common.Hash]snapshot),
+		baseTime: time.Now(),
 	}
+
+	// If user provided threshold smaller than minimum, set to minimum
+	if config.DiskRootThreshold < minTimeThreshold {
+		config.DiskRootThreshold = minTimeThreshold
+	}
+
 	// Attempt to load a previously persisted snapshot and rebuild one if failed
 	head, disabled, err := loadSnapshot(diskdb, triedb, root, config.CacheSize, config.Recovery, config.NoBuild)
 	if disabled {
@@ -500,7 +511,7 @@ func (t *Tree) cap(diff *diffLayer, layers int) *diskLayer {
 			t.onFlatten()
 		}
 		diff.parent = flattened
-		if flattened.memory < aggregatorMemoryLimit {
+		if (flattened.memory < aggregatorMemoryLimit) && !t.isPastThreshold() {
 			// Accumulator layer is smaller than the limit, so we can abort, unless
 			// there's a snapshot being generated currently. In that case, the trie
 			// will move from underneath the generator so we **must** merge all the
@@ -512,13 +523,16 @@ func (t *Tree) cap(diff *diffLayer, layers int) *diskLayer {
 	default:
 		panic(fmt.Sprintf("unknown data layer: %T", parent))
 	}
-	// If the bottom-most layer is larger than our memory cap, persist to disk
+	// If the bottom-most layer is larger than our memory cap or time elapsed greater than threshold, persist to disk
 	bottom := diff.parent.(*diffLayer)
 
 	bottom.lock.RLock()
 	base := diffToDisk(bottom)
 	bottom.lock.RUnlock()
 
+	// Reset the time reference for next update
+	t.baseTime = time.Now()
+
 	t.layers[base.root] = base
 	diff.parent = base
 	return base
@@ -885,3 +899,9 @@ func (t *Tree) Size() (diffs common.StorageSize, buf common.StorageSize) {
 	}
 	return size, 0
 }
+
+// Check if time threshold is enabled and if the time elapsed is more than the threshold.
+// if false, we can abort else we proceed to update the disk root
+func (t *Tree) isPastThreshold() bool {
+	return (t.config.EnableDiskRootInterval && (time.Since(t.baseTime) > t.config.DiskRootThreshold))
+}

core/state/snapshot/snapshot_test.go

@@ -330,6 +330,103 @@ func TestPostCapBasicDataAccess(t *testing.T) {
 	}
 }
 
+func TestForceSnapRootCaps(t *testing.T) {
+	// setAccount is a helper to construct a random account entry and assign it to
+	// an account slot in a snapshot
+	setAccount := func(accKey string) map[common.Hash][]byte {
+		return map[common.Hash][]byte{
+			common.HexToHash(accKey): randomAccount(),
+		}
+	}
+	makeRoot := func(height uint64) common.Hash {
+		var buffer [8]byte
+		binary.BigEndian.PutUint64(buffer[:], height)
+		return common.BytesToHash(buffer[:])
+	}
+	var (
+		last = common.HexToHash("0x01")
+		head common.Hash
+	)
+	// Create a starting base layer and a snapshot tree out of it
+	base := &diskLayer{
+		diskdb: rawdb.NewMemoryDatabase(),
+		root:   common.HexToHash("0x01"),
+		cache:  fastcache.New(1024 * 500),
+	}
+	snaps := &Tree{
+		layers: map[common.Hash]snapshot{
+			base.root: base,
+		},
+		baseTime: time.Now(),
+		config: Config{
+			EnableDiskRootInterval: true,
+			DiskRootThreshold:      30 * time.Minute,
+		},
+	}
+
+	// adding layers to the tree more than 128
+	for i := 0; i < 150; i++ {
+		head = makeRoot(uint64(i + 2))
+		snaps.Update(head, last, nil, setAccount(fmt.Sprintf("%d", i+2)), nil)
+		last = head
+	}
+
+	// Currently the tree should have all the 150 layers + disk layer
+	if count := len(snaps.layers); count != 151 {
+		t.Errorf("Unexpected number of layers - count %d, expected 151", count)
+	}
+
+	// Now capping without time threshold reached
+	if err := snaps.Cap(head, 128); err != nil {
+		t.Error("Error while capping layers", err)
+	}
+
+	// the diskRoot should not have been updated yet since
+	// the time and the memory limit have not been reached
+	if firstDiskRoot := snaps.diskRoot(); firstDiskRoot != base.root {
+		t.Errorf("Disk root should not have updated at this point - actual: %s, expected: %s", firstDiskRoot, base.root)
+	}
+
+	// layers beyond 128 should be flattened into one so total layers
+	// 128 top layers + 1 flattened layer + disk layer
+	if newLayers := len(snaps.layers); newLayers != 130 {
+		t.Errorf("Unexpected number of layers after flatten - count: %d, expected: 130", newLayers)
+	}
+
+	// Setting baseTime 100 min behind to trigger disk update
+	snaps.baseTime = time.Now().Add(time.Duration(-100) * time.Minute)
+
+	// Check if forceSnapshot disabled, time threshold should not trigger snapshot
+	snaps.config.EnableDiskRootInterval = false
+	if err := snaps.Cap(head, 128); err != nil {
+		t.Error("Error while capping layers", err)
+	}
+
+	// the diskRoot should not have been updated yet since
+	// the force snapshot is disabled
+	if firstDiskRoot := snaps.diskRoot(); firstDiskRoot != base.root {
+		t.Errorf("Disk root should not have updated at this point - actual: %s, expected: %s", firstDiskRoot, base.root)
+	}
+
+	// Re-enable forceSnapshot, time threshold should trigger snapshot
+	snaps.config.EnableDiskRootInterval = true
+	if err := snaps.Cap(head, 128); err != nil {
+		t.Error("Error while capping layers", err)
+	}
+
+	// the diskRoot should have been updated now since the time and the memory limit
+	// have not been reached
+	if updatedDiskRoot := snaps.diskRoot(); updatedDiskRoot == base.root {
+		t.Errorf("Disk root did not update at this point - actual: %s", updatedDiskRoot)
+	}
+
+	// disk layer should be updated now to be the flattened layer
+	// 128 top layers + disk layer
+	if newLayers := len(snaps.layers); newLayers != 129 {
+		t.Errorf("Unexpected number of layers after flatten - count: %d, expected: 130", newLayers)
+	}
+}
+
 // TestSnaphots tests the functionality for retrieving the snapshot
 // with given head root and the desired depth.
 func TestSnaphots(t *testing.T) {

eth/backend.go

@@ -190,15 +190,17 @@ func New(stack *node.Node, config *ethconfig.Config) (*Ethereum, error) {
 			EnablePreimageRecording: config.EnablePreimageRecording,
 		}
 		cacheConfig = &core.CacheConfig{
-			TrieCleanLimit:      config.TrieCleanCache,
-			TrieCleanNoPrefetch: config.NoPrefetch,
-			TrieDirtyLimit:      config.TrieDirtyCache,
-			TrieDirtyDisabled:   config.NoPruning,
-			TrieTimeLimit:       config.TrieTimeout,
-			SnapshotLimit:       config.SnapshotCache,
-			Preimages:           config.Preimages,
-			StateHistory:        config.StateHistory,
-			StateScheme:         scheme,
+			TrieCleanLimit:         config.TrieCleanCache,
+			TrieCleanNoPrefetch:    config.NoPrefetch,
+			TrieDirtyLimit:         config.TrieDirtyCache,
+			TrieDirtyDisabled:      config.NoPruning,
+			TrieTimeLimit:          config.TrieTimeout,
+			SnapshotLimit:          config.SnapshotCache,
+			Preimages:              config.Preimages,
+			StateHistory:           config.StateHistory,
+			StateScheme:            scheme,
+			EnableDiskRootInterval: config.EnableDiskRootInterval,
+			DiskRootThreshold:      config.DiskRootThreshold,
 		}
 	)
 	if config.VMTrace != "" {

eth/ethconfig/config.go

@@ -48,25 +48,27 @@ var FullNodeGPO = gasprice.Config{
 
 // Defaults contains default settings for use on the Ethereum main net.
 var Defaults = Config{
-	SyncMode:           downloader.SnapSync,
-	NetworkId:          0, // enable auto configuration of networkID == chainID
-	TxLookupLimit:      2350000,
-	TransactionHistory: 2350000,
-	StateHistory:       params.FullImmutabilityThreshold,
-	LightPeers:         100,
-	DatabaseCache:      512,
-	TrieCleanCache:     154,
-	TrieDirtyCache:     256,
-	TrieTimeout:        60 * time.Minute,
-	SnapshotCache:      102,
-	FilterLogCacheSize: 32,
-	Miner:              miner.DefaultConfig,
-	TxPool:             legacypool.DefaultConfig,
-	BlobPool:           blobpool.DefaultConfig,
-	RPCGasCap:          50000000,
-	RPCEVMTimeout:      5 * time.Second,
-	GPO:                FullNodeGPO,
-	RPCTxFeeCap:        1, // 1 ether
+	SyncMode:               downloader.SnapSync,
+	NetworkId:              0, // enable auto configuration of networkID == chainID
+	TxLookupLimit:          2350000,
+	TransactionHistory:     2350000,
+	StateHistory:           params.FullImmutabilityThreshold,
+	LightPeers:             100,
+	DatabaseCache:          512,
+	TrieCleanCache:         154,
+	TrieDirtyCache:         256,
+	TrieTimeout:            60 * time.Minute,
+	SnapshotCache:          102,
+	EnableDiskRootInterval: false,
+	DiskRootThreshold:      60 * time.Minute,
+	FilterLogCacheSize:     32,
+	Miner:                  miner.DefaultConfig,
+	TxPool:                 legacypool.DefaultConfig,
+	BlobPool:               blobpool.DefaultConfig,
+	RPCGasCap:              50000000,
+	RPCEVMTimeout:          5 * time.Second,
+	GPO:                    FullNodeGPO,
+	RPCTxFeeCap:            1, // 1 ether
 }
 
 //go:generate go run github.com/fjl/gencodec -type Config -formats toml -out gen_config.go
@@ -119,11 +121,13 @@ type Config struct {
 	DatabaseCache      int
 	DatabaseFreezer    string
 
-	TrieCleanCache int
-	TrieDirtyCache int
-	TrieTimeout    time.Duration
-	SnapshotCache  int
-	Preimages      bool
+	TrieCleanCache         int
+	TrieDirtyCache         int
+	TrieTimeout            time.Duration
+	SnapshotCache          int
+	Preimages              bool
+	EnableDiskRootInterval bool
+	DiskRootThreshold      time.Duration
 
 	// This is the number of blocks for which logs will be cached in the filter system.
 	FilterLogCacheSize int

eth/ethconfig/gen_config.go

@@ -44,6 +44,8 @@ func (c Config) MarshalTOML() (interface{}, error) {
 		TrieTimeout             time.Duration
 		SnapshotCache           int
 		Preimages               bool
+		EnableDiskRootInterval  bool
+		DiskRootThreshold       time.Duration
 		FilterLogCacheSize      int
 		Miner                   miner.Config
 		TxPool                  legacypool.Config
@@ -87,6 +89,8 @@ func (c Config) MarshalTOML() (interface{}, error) {
 	enc.TrieTimeout = c.TrieTimeout
 	enc.SnapshotCache = c.SnapshotCache
 	enc.Preimages = c.Preimages
+	enc.EnableDiskRootInterval = c.EnableDiskRootInterval
+	enc.DiskRootThreshold = c.DiskRootThreshold
 	enc.FilterLogCacheSize = c.FilterLogCacheSize
 	enc.Miner = c.Miner
 	enc.TxPool = c.TxPool
@@ -134,6 +138,8 @@ func (c *Config) UnmarshalTOML(unmarshal func(interface{}) error) error {
 		TrieTimeout             *time.Duration
 		SnapshotCache           *int
 		Preimages               *bool
+		EnableDiskRootInterval  *bool
+		DiskRootThreshold       *time.Duration
 		FilterLogCacheSize      *int
 		Miner                   *miner.Config
 		TxPool                  *legacypool.Config
@@ -234,6 +240,12 @@ func (c *Config) UnmarshalTOML(unmarshal func(interface{}) error) error {
 	if dec.Preimages != nil {
 		c.Preimages = *dec.Preimages
 	}
+	if dec.EnableDiskRootInterval != nil {
+		c.EnableDiskRootInterval = *dec.EnableDiskRootInterval
+	}
+	if dec.DiskRootThreshold != nil {
+		c.DiskRootThreshold = *dec.DiskRootThreshold
+	}
 	if dec.FilterLogCacheSize != nil {
 		c.FilterLogCacheSize = *dec.FilterLogCacheSize
 	}