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core/rawdb, core/state/snapshot: runtime snapshot generation

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This commit is contained in:
Péter Szilágyi
2019-11-26 09:48:29 +02:00
parent f300c0df01
commit 351a5903b0
21 changed files with 1551 additions and 486 deletions
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270
core/state/snapshot/snapshot.go
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@ -18,31 +18,67 @@
package snapshot
import (
"bytes"
"errors"
"fmt"
"os"
"io"
"sync"
"github.com/VictoriaMetrics/fastcache"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/rawdb"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/metrics"
"github.com/ethereum/go-ethereum/rlp"
"github.com/ethereum/go-ethereum/trie"
)
var (
snapshotCleanHitMeter = metrics.NewRegisteredMeter("state/snapshot/clean/hit", nil)
snapshotCleanMissMeter = metrics.NewRegisteredMeter("state/snapshot/clean/miss", nil)
snapshotCleanReadMeter = metrics.NewRegisteredMeter("state/snapshot/clean/read", nil)
snapshotCleanWriteMeter = metrics.NewRegisteredMeter("state/snapshot/clean/write", nil)
snapshotCleanAccountHitMeter = metrics.NewRegisteredMeter("state/snapshot/clean/account/hit", nil)
snapshotCleanAccountMissMeter = metrics.NewRegisteredMeter("state/snapshot/clean/account/miss", nil)
snapshotCleanAccountReadMeter = metrics.NewRegisteredMeter("state/snapshot/clean/account/read", nil)
snapshotCleanAccountWriteMeter = metrics.NewRegisteredMeter("state/snapshot/clean/account/write", nil)
snapshotCleanStorageHitMeter = metrics.NewRegisteredMeter("state/snapshot/clean/storage/hit", nil)
snapshotCleanStorageMissMeter = metrics.NewRegisteredMeter("state/snapshot/clean/storage/miss", nil)
snapshotCleanStorageReadMeter = metrics.NewRegisteredMeter("state/snapshot/clean/storage/read", nil)
snapshotCleanStorageWriteMeter = metrics.NewRegisteredMeter("state/snapshot/clean/storage/write", nil)
snapshotDirtyAccountHitMeter = metrics.NewRegisteredMeter("state/snapshot/dirty/account/hit", nil)
snapshotDirtyAccountMissMeter = metrics.NewRegisteredMeter("state/snapshot/dirty/account/miss", nil)
snapshotDirtyAccountReadMeter = metrics.NewRegisteredMeter("state/snapshot/dirty/account/read", nil)
snapshotDirtyAccountWriteMeter = metrics.NewRegisteredMeter("state/snapshot/dirty/account/write", nil)
snapshotDirtyStorageHitMeter = metrics.NewRegisteredMeter("state/snapshot/dirty/storage/hit", nil)
snapshotDirtyStorageMissMeter = metrics.NewRegisteredMeter("state/snapshot/dirty/storage/miss", nil)
snapshotDirtyStorageReadMeter = metrics.NewRegisteredMeter("state/snapshot/dirty/storage/read", nil)
snapshotDirtyStorageWriteMeter = metrics.NewRegisteredMeter("state/snapshot/dirty/storage/write", nil)
snapshotFlushAccountItemMeter = metrics.NewRegisteredMeter("state/snapshot/flush/account/item", nil)
snapshotFlushAccountSizeMeter = metrics.NewRegisteredMeter("state/snapshot/flush/account/size", nil)
snapshotFlushStorageItemMeter = metrics.NewRegisteredMeter("state/snapshot/flush/storage/item", nil)
snapshotFlushStorageSizeMeter = metrics.NewRegisteredMeter("state/snapshot/flush/storage/size", nil)
snapshotBloomIndexTimer = metrics.NewRegisteredResettingTimer("state/snapshot/bloom/index", nil)
snapshotBloomErrorGauge = metrics.NewRegisteredGaugeFloat64("state/snapshot/bloom/error", nil)
snapshotBloomAccountTrueHitMeter = metrics.NewRegisteredMeter("state/snapshot/bloom/account/truehit", nil)
snapshotBloomAccountFalseHitMeter = metrics.NewRegisteredMeter("state/snapshot/bloom/account/falsehit", nil)
snapshotBloomAccountMissMeter = metrics.NewRegisteredMeter("state/snapshot/bloom/account/miss", nil)
snapshotBloomStorageTrueHitMeter = metrics.NewRegisteredMeter("state/snapshot/bloom/storage/truehit", nil)
snapshotBloomStorageFalseHitMeter = metrics.NewRegisteredMeter("state/snapshot/bloom/storage/falsehit", nil)
snapshotBloomStorageMissMeter = metrics.NewRegisteredMeter("state/snapshot/bloom/storage/miss", nil)
// ErrSnapshotStale is returned from data accessors if the underlying snapshot
// layer had been invalidated due to the chain progressing forward far enough
// to not maintain the layer's original state.
ErrSnapshotStale = errors.New("snapshot stale")
// ErrNotCoveredYet is returned from data accessors if the underlying snapshot
// is being generated currently and the requested data item is not yet in the
// range of accounts covered.
ErrNotCoveredYet = errors.New("not covered yet")
// errSnapshotCycle is returned if a snapshot is attempted to be inserted
// that forms a cycle in the snapshot tree.
errSnapshotCycle = errors.New("snapshot cycle")
@ -79,7 +115,7 @@ type snapshot interface {
// Journal commits an entire diff hierarchy to disk into a single journal file.
// This is meant to be used during shutdown to persist the snapshot without
// flattening everything down (bad for reorgs).
Journal() error
Journal(path string) (io.WriteCloser, common.Hash, error)
// Stale return whether this layer has become stale (was flattened across) or
// if it's still live.
@ -96,7 +132,10 @@ type snapshot interface {
// 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 {
layers map[common.Hash]snapshot // Collection of all known layers // TODO(karalabe): split Clique overlaps
diskdb ethdb.KeyValueStore // Persistent database to store the snapshot
triedb *trie.Database // In-memory cache to access the trie through
cache int // Megabytes permitted to use for read caches
layers map[common.Hash]snapshot // Collection of all known layers
lock sync.RWMutex
}
@ -105,20 +144,24 @@ type Tree struct {
// of the snapshot matches the expected one.
//
// If the snapshot is missing or inconsistent, the entirety is deleted and will
// be reconstructed from scratch based on the tries in the key-value store.
func New(db ethdb.KeyValueStore, journal string, root common.Hash) (*Tree, error) {
// Attempt to load a previously persisted snapshot
head, err := loadSnapshot(db, journal, root)
if err != nil {
log.Warn("Failed to load snapshot, regenerating", "err", err)
if head, err = generateSnapshot(db, journal, root); err != nil {
return nil, err
}
}
// Existing snapshot loaded or one regenerated, seed all the layers
// be reconstructed from scratch based on the tries in the key-value store, on a
// background thread.
func New(diskdb ethdb.KeyValueStore, triedb *trie.Database, journal string, cache int, root common.Hash) *Tree {
// Create a new, empty snapshot tree
snap := &Tree{
diskdb: diskdb,
triedb: triedb,
cache: cache,
layers: make(map[common.Hash]snapshot),
}
// Attempt to load a previously persisted snapshot and rebuild one if failed
head, err := loadSnapshot(diskdb, triedb, journal, cache, root)
if err != nil {
log.Warn("Failed to load snapshot, regenerating", "err", err)
snap.Rebuild(root)
return snap
}
// Existing snapshot loaded, seed all the layers
for head != nil {
snap.layers[head.Root()] = head
@ -131,7 +174,7 @@ func New(db ethdb.KeyValueStore, journal string, root common.Hash) (*Tree, error
panic(fmt.Sprintf("unknown data layer: %T", self))
}
}
return snap, nil
return snap
}
// Snapshot retrieves a snapshot belonging to the given block root, or nil if no
@ -173,7 +216,7 @@ func (t *Tree) Update(blockRoot common.Hash, parentRoot common.Hash, accounts ma
// Cap traverses downwards the snapshot tree from a head block hash until the
// number of allowed layers are crossed. All layers beyond the permitted number
// are flattened downwards.
func (t *Tree) Cap(root common.Hash, layers int, memory uint64) error {
func (t *Tree) Cap(root common.Hash, layers int) error {
// Retrieve the head snapshot to cap from
snap := t.Snapshot(root)
if snap == nil {
@ -190,6 +233,8 @@ func (t *Tree) Cap(root common.Hash, layers int, memory uint64) error {
// Flattening the bottom-most diff layer requires special casing since there's
// no child to rewire to the grandparent. In that case we can fake a temporary
// child for the capping and then remove it.
var persisted *diskLayer
switch layers {
case 0:
// If full commit was requested, flatten the diffs and merge onto disk
@ -210,7 +255,7 @@ func (t *Tree) Cap(root common.Hash, layers int, memory uint64) error {
)
diff.lock.RLock()
bottom = diff.flatten().(*diffLayer)
if bottom.memory >= memory {
if bottom.memory >= aggregatorMemoryLimit {
base = diffToDisk(bottom)
}
diff.lock.RUnlock()
@ -225,7 +270,7 @@ func (t *Tree) Cap(root common.Hash, layers int, memory uint64) error {
default:
// Many layers requested to be retained, cap normally
t.cap(diff, layers, memory)
persisted = t.cap(diff, layers)
}
// Remove any layer that is stale or links into a stale layer
children := make(map[common.Hash][]common.Hash)
@ -248,13 +293,28 @@ func (t *Tree) Cap(root common.Hash, layers int, memory uint64) error {
remove(root)
}
}
// If the disk layer was modified, regenerate all the cummulative blooms
if persisted != nil {
var rebloom func(root common.Hash)
rebloom = func(root common.Hash) {
if diff, ok := t.layers[root].(*diffLayer); ok {
diff.rebloom(persisted)
}
for _, child := range children[root] {
rebloom(child)
}
}
rebloom(persisted.root)
}
return nil
}
// cap traverses downwards the diff tree until the number of allowed layers are
// crossed. All diffs beyond the permitted number are flattened downwards. If the
// layer limit is reached, memory cap is also enforced (but not before).
func (t *Tree) cap(diff *diffLayer, layers int, memory uint64) {
//
// The method returns the new disk layer if diffs were persistend into it.
func (t *Tree) cap(diff *diffLayer, layers int) *diskLayer {
// Dive until we run out of layers or reach the persistent database
for ; layers > 2; layers-- {
// If we still have diff layers below, continue down
@ -262,14 +322,14 @@ func (t *Tree) cap(diff *diffLayer, layers int, memory uint64) {
diff = parent
} else {
// Diff stack too shallow, return without modifications
return
return nil
}
}
// We're out of layers, flatten anything below, stopping if it's the disk or if
// the memory limit is not yet exceeded.
switch parent := diff.parent.(type) {
case *diskLayer:
return
return nil
case *diffLayer:
// Flatten the parent into the grandparent. The flattening internally obtains a
@ -281,8 +341,14 @@ func (t *Tree) cap(diff *diffLayer, layers int, memory uint64) {
defer diff.lock.Unlock()
diff.parent = flattened
if flattened.memory < memory {
return
if flattened.memory < aggregatorMemoryLimit {
// 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 fron underneath the generator so we **must** merge all the
// partial data down into the snapshot and restart the generation.
if flattened.parent.(*diskLayer).genAbort == nil {
return nil
}
}
default:
panic(fmt.Sprintf("unknown data layer: %T", parent))
@ -296,6 +362,7 @@ func (t *Tree) cap(diff *diffLayer, layers int, memory uint64) {
t.layers[base.root] = base
diff.parent = base
return base
}
// diffToDisk merges a bottom-most diff into the persistent disk layer underneath
@ -303,8 +370,15 @@ func (t *Tree) cap(diff *diffLayer, layers int, memory uint64) {
func diffToDisk(bottom *diffLayer) *diskLayer {
var (
base = bottom.parent.(*diskLayer)
batch = base.db.NewBatch()
batch = base.diskdb.NewBatch()
stats *generatorStats
)
// If the disk layer is running a snapshot generator, abort it
if base.genAbort != nil {
abort := make(chan *generatorStats)
base.genAbort <- abort
stats = <-abort
}
// Start by temporarily deleting the current snapshot block marker. This
// ensures that in the case of a crash, the entire snapshot is invalidated.
rawdb.DeleteSnapshotRoot(batch)
@ -319,6 +393,10 @@ func diffToDisk(bottom *diffLayer) *diskLayer {
// Push all the accounts into the database
for hash, data := range bottom.accountData {
// Skip any account not covered yet by the snapshot
if base.genMarker != nil && bytes.Compare(hash[:], base.genMarker) > 0 {
continue
}
if len(data) > 0 {
// Account was updated, push to disk
rawdb.WriteAccountSnapshot(batch, hash, data)
@ -335,19 +413,35 @@ func diffToDisk(bottom *diffLayer) *diskLayer {
rawdb.DeleteAccountSnapshot(batch, hash)
base.cache.Set(hash[:], nil)
it := rawdb.IterateStorageSnapshots(base.db, hash)
it := rawdb.IterateStorageSnapshots(base.diskdb, hash)
for it.Next() {
if key := it.Key(); len(key) == 65 { // TODO(karalabe): Yuck, we should move this into the iterator
batch.Delete(key)
base.cache.Del(key[1:])
snapshotFlushStorageItemMeter.Mark(1)
snapshotFlushStorageSizeMeter.Mark(int64(len(data)))
}
}
it.Release()
}
snapshotFlushAccountItemMeter.Mark(1)
snapshotFlushAccountSizeMeter.Mark(int64(len(data)))
}
// Push all the storage slots into the database
for accountHash, storage := range bottom.storageData {
// Skip any account not covered yet by the snapshot
if base.genMarker != nil && bytes.Compare(accountHash[:], base.genMarker) > 0 {
continue
}
// Generation might be mid-account, track that case too
midAccount := base.genMarker != nil && bytes.Equal(accountHash[:], base.genMarker[:common.HashLength])
for storageHash, data := range storage {
// Skip any slot not covered yet by the snapshot
if midAccount && bytes.Compare(storageHash[:], base.genMarker[common.HashLength:]) > 0 {
continue
}
if len(data) > 0 {
rawdb.WriteStorageSnapshot(batch, accountHash, storageHash, data)
base.cache.Set(append(accountHash[:], storageHash[:]...), data)
@ -355,6 +449,8 @@ func diffToDisk(bottom *diffLayer) *diskLayer {
rawdb.DeleteStorageSnapshot(batch, accountHash, storageHash)
base.cache.Set(append(accountHash[:], storageHash[:]...), nil)
}
snapshotFlushStorageItemMeter.Mark(1)
snapshotFlushStorageSizeMeter.Mark(int64(len(data)))
}
if batch.ValueSize() > ethdb.IdealBatchSize {
if err := batch.Write(); err != nil {
@ -368,65 +464,91 @@ func diffToDisk(bottom *diffLayer) *diskLayer {
if err := batch.Write(); err != nil {
log.Crit("Failed to write leftover snapshot", "err", err)
}
return &diskLayer{
root: bottom.root,
cache: base.cache,
db: base.db,
journal: base.journal,
res := &diskLayer{
root: bottom.root,
cache: base.cache,
diskdb: base.diskdb,
triedb: base.triedb,
genMarker: base.genMarker,
}
// If snapshot generation hasn't finished yet, port over all the starts and
// continue where the previous round left off.
//
// Note, the `base.genAbort` comparison is not used normally, it's checked
// to allow the tests to play with the marker without triggering this path.
if base.genMarker != nil && base.genAbort != nil {
res.genMarker = base.genMarker
res.genAbort = make(chan chan *generatorStats)
go res.generate(stats)
}
return res
}
// Journal commits an entire diff hierarchy to disk into a single journal file.
// This is meant to be used during shutdown to persist the snapshot without
// flattening everything down (bad for reorgs).
func (t *Tree) Journal(blockRoot common.Hash) error {
//
// The method returns the root hash of the base layer that needs to be persisted
// to disk as a trie too to allow continuing any pending generation op.
func (t *Tree) Journal(root common.Hash, path string) (common.Hash, error) {
// Retrieve the head snapshot to journal from var snap snapshot
snap := t.Snapshot(blockRoot)
snap := t.Snapshot(root)
if snap == nil {
return fmt.Errorf("snapshot [%#x] missing", blockRoot)
return common.Hash{}, fmt.Errorf("snapshot [%#x] missing", root)
}
// Run the journaling
t.lock.Lock()
defer t.lock.Unlock()
return snap.(snapshot).Journal()
writer, base, err := snap.(snapshot).Journal(path)
if err != nil {
return common.Hash{}, err
}
return base, writer.Close()
}
// loadSnapshot loads a pre-existing state snapshot backed by a key-value store.
func loadSnapshot(db ethdb.KeyValueStore, journal string, root common.Hash) (snapshot, error) {
// Retrieve the block number and hash of the snapshot, failing if no snapshot
// is present in the database (or crashed mid-update).
baseRoot := rawdb.ReadSnapshotRoot(db)
if baseRoot == (common.Hash{}) {
return nil, errors.New("missing or corrupted snapshot")
}
base := &diskLayer{
journal: journal,
db: db,
cache: fastcache.New(512 * 1024 * 1024),
root: baseRoot,
}
// Load all the snapshot diffs from the journal, failing if their chain is broken
// or does not lead from the disk snapshot to the specified head.
if _, err := os.Stat(journal); os.IsNotExist(err) {
// Journal doesn't exist, don't worry if it's not supposed to
if baseRoot != root {
return nil, fmt.Errorf("snapshot journal missing, head doesn't match snapshot: have %#x, want %#x", baseRoot, root)
// Rebuild wipes all available snapshot data from the persistent database and
// discard all caches and diff layers. Afterwards, it starts a new snapshot
// generator with the given root hash.
func (t *Tree) Rebuild(root common.Hash) {
t.lock.Lock()
defer t.lock.Unlock()
// Track whether there's a wipe currently running and keep it alive if so
var wiper chan struct{}
// Iterate over and mark all layers stale
for _, layer := range t.layers {
switch layer := layer.(type) {
case *diskLayer:
// If the base layer is generating, abort it and save
if layer.genAbort != nil {
abort := make(chan *generatorStats)
layer.genAbort <- abort
if stats := <-abort; stats != nil {
wiper = stats.wiping
}
}
// Layer should be inactive now, mark it as stale
layer.lock.Lock()
layer.stale = true
layer.lock.Unlock()
case *diffLayer:
// If the layer is a simple diff, simply mark as stale
layer.lock.Lock()
layer.stale = true
layer.lock.Unlock()
default:
panic(fmt.Sprintf("unknown layer type: %T", layer))
}
return base, nil
}
file, err := os.Open(journal)
if err != nil {
return nil, err
// Start generating a new snapshot from scratch on a backgroung thread. The
// generator will run a wiper first if there's not one running right now.
log.Info("Rebuilding state snapshot")
t.layers = map[common.Hash]snapshot{
root: generateSnapshot(t.diskdb, t.triedb, t.cache, root, wiper),
}
snapshot, err := loadDiffLayer(base, rlp.NewStream(file, 0))
if err != nil {
return nil, err
}
// Entire snapshot journal loaded, sanity check the head and return
// Journal doesn't exist, don't worry if it's not supposed to
if head := snapshot.Root(); head != root {
return nil, fmt.Errorf("head doesn't match snapshot: have %#x, want %#x", head, root)
}
return snapshot, nil
}