plugeth/core/rawdb/freezer.go
AusIV 3ebfeb09fe
core/rawdb: fix high memory usage in freezer (#21243)
The ancients variable in the freezer is a list of hashes, which
identifies all of the hashes to be frozen. The slice is being allocated
with a capacity of `limit`, which is the number of the last block
this batch will attempt to add to the freezer. That means we are
allocating memory for all of the blocks in the freezer, not just
the ones to be added.

If instead we allocate `limit - f.frozen`, we will only allocate
enough space for the blocks we're about to add to the freezer. On
mainnet this reduces usage by about 320 MB.
2020-06-19 10:51:37 +03:00

412 lines
13 KiB
Go

// 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"
"fmt"
"math"
"os"
"path/filepath"
"sync/atomic"
"time"
"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/ethereum/go-ethereum/params"
"github.com/prometheus/tsdb/fileutil"
)
var (
// errUnknownTable is returned if the user attempts to read from a table that is
// not tracked by the freezer.
errUnknownTable = errors.New("unknown table")
// errOutOrderInsertion is returned if the user attempts to inject out-of-order
// binary blobs into the freezer.
errOutOrderInsertion = errors.New("the append operation is out-order")
// errSymlinkDatadir is returned if the ancient directory specified by user
// is a symbolic link.
errSymlinkDatadir = errors.New("symbolic link datadir is not supported")
)
const (
// freezerRecheckInterval is the frequency to check the key-value database for
// chain progression that might permit new blocks to be frozen into immutable
// storage.
freezerRecheckInterval = time.Minute
// freezerBatchLimit is the maximum number of blocks to freeze in one batch
// before doing an fsync and deleting it from the key-value store.
freezerBatchLimit = 30000
)
// freezer is an memory mapped append-only database to store immutable chain data
// into flat files:
//
// - The append only nature ensures that disk writes are minimized.
// - The memory mapping ensures we can max out system memory for caching without
// reserving it for go-ethereum. This would also reduce the memory requirements
// of Geth, and thus also GC overhead.
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
tables map[string]*freezerTable // Data tables for storing everything
instanceLock fileutil.Releaser // File-system lock to prevent double opens
quit chan struct{}
}
// newFreezer creates a chain freezer that moves ancient chain data into
// append-only flat file containers.
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)
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) {
if info.Mode()&os.ModeSymlink != 0 {
log.Warn("Symbolic link ancient database is not supported", "path", datadir)
return nil, errSymlinkDatadir
}
}
// Leveldb uses LOCK as the filelock filename. To prevent the
// name collision, we use FLOCK as the lock name.
lock, _, err := fileutil.Flock(filepath.Join(datadir, "FLOCK"))
if err != nil {
return nil, err
}
// Open all the supported data tables
freezer := &freezer{
tables: make(map[string]*freezerTable),
instanceLock: lock,
quit: make(chan struct{}),
}
for name, disableSnappy := range freezerNoSnappy {
table, err := newTable(datadir, name, readMeter, writeMeter, sizeGauge, disableSnappy)
if err != nil {
for _, table := range freezer.tables {
table.Close()
}
lock.Release()
return nil, err
}
freezer.tables[name] = table
}
if err := freezer.repair(); err != nil {
for _, table := range freezer.tables {
table.Close()
}
lock.Release()
return nil, err
}
log.Info("Opened ancient database", "database", datadir)
return freezer, nil
}
// Close terminates the chain freezer, unmapping all the data files.
func (f *freezer) Close() error {
f.quit <- struct{}{}
var errs []error
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 errs != nil {
return fmt.Errorf("%v", errs)
}
return nil
}
// HasAncient returns an indicator whether the specified ancient data exists
// in the freezer.
func (f *freezer) HasAncient(kind string, number uint64) (bool, error) {
if table := f.tables[kind]; table != nil {
return table.has(number), nil
}
return false, nil
}
// Ancient retrieves an ancient binary blob from the append-only immutable files.
func (f *freezer) Ancient(kind string, number uint64) ([]byte, error) {
if table := f.tables[kind]; table != nil {
return table.Retrieve(number)
}
return nil, errUnknownTable
}
// Ancients returns the length of the frozen items.
func (f *freezer) Ancients() (uint64, error) {
return atomic.LoadUint64(&f.frozen), nil
}
// AncientSize returns the ancient size of the specified category.
func (f *freezer) AncientSize(kind string) (uint64, error) {
if table := f.tables[kind]; table != nil {
return table.size()
}
return 0, errUnknownTable
}
// AppendAncient injects all binary blobs belong to block at the end of the
// append-only immutable table files.
//
// Notably, this function is lock free but kind of thread-safe. All out-of-order
// injection will be rejected. But if two injections with same number happen at
// the same time, we can get into the trouble.
func (f *freezer) AppendAncient(number uint64, hash, header, body, receipts, td []byte) (err error) {
// Ensure the binary blobs we are appending is continuous with freezer.
if atomic.LoadUint64(&f.frozen) != number {
return errOutOrderInsertion
}
// Rollback all inserted data if any insertion below failed to ensure
// the tables won't out of sync.
defer func() {
if err != nil {
rerr := f.repair()
if rerr != nil {
log.Crit("Failed to repair freezer", "err", rerr)
}
log.Info("Append ancient failed", "number", number, "err", err)
}
}()
// Inject all the components into the relevant data tables
if err := f.tables[freezerHashTable].Append(f.frozen, hash[:]); err != nil {
log.Error("Failed to append ancient hash", "number", f.frozen, "hash", hash, "err", err)
return err
}
if err := f.tables[freezerHeaderTable].Append(f.frozen, header); err != nil {
log.Error("Failed to append ancient header", "number", f.frozen, "hash", hash, "err", err)
return err
}
if err := f.tables[freezerBodiesTable].Append(f.frozen, body); err != nil {
log.Error("Failed to append ancient body", "number", f.frozen, "hash", hash, "err", err)
return err
}
if err := f.tables[freezerReceiptTable].Append(f.frozen, receipts); err != nil {
log.Error("Failed to append ancient receipts", "number", f.frozen, "hash", hash, "err", err)
return err
}
if err := f.tables[freezerDifficultyTable].Append(f.frozen, td); err != nil {
log.Error("Failed to append ancient difficulty", "number", f.frozen, "hash", hash, "err", err)
return err
}
atomic.AddUint64(&f.frozen, 1) // Only modify atomically
return nil
}
// Truncate discards any recent data above the provided threshold number.
func (f *freezer) TruncateAncients(items uint64) error {
if atomic.LoadUint64(&f.frozen) <= items {
return nil
}
for _, table := range f.tables {
if err := table.truncate(items); err != nil {
return err
}
}
atomic.StoreUint64(&f.frozen, items)
return nil
}
// sync flushes all data tables to disk.
func (f *freezer) Sync() error {
var errs []error
for _, table := range f.tables {
if err := table.Sync(); err != nil {
errs = append(errs, err)
}
}
if errs != nil {
return fmt.Errorf("%v", errs)
}
return nil
}
// freeze is a background thread that periodically checks the blockchain for any
// import progress and moves ancient data from the fast database into the freezer.
//
// This functionality is deliberately broken off from block importing to avoid
// incurring additional data shuffling delays on block propagation.
func (f *freezer) freeze(db ethdb.KeyValueStore) {
nfdb := &nofreezedb{KeyValueStore: db}
backoff := false
for {
select {
case <-f.quit:
log.Info("Freezer shutting down")
return
default:
}
if backoff {
select {
case <-time.NewTimer(freezerRecheckInterval).C:
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
backoff = true
continue
}
number := ReadHeaderNumber(nfdb, hash)
switch {
case number == nil:
log.Error("Current full block number unavailable", "hash", hash)
backoff = true
continue
case *number < params.ImmutabilityThreshold:
log.Debug("Current full block not old enough", "number", *number, "hash", hash, "delay", params.ImmutabilityThreshold)
backoff = true
continue
case *number-params.ImmutabilityThreshold <= f.frozen:
log.Debug("Ancient blocks frozen already", "number", *number, "hash", hash, "frozen", f.frozen)
backoff = true
continue
}
head := ReadHeader(nfdb, hash, *number)
if head == nil {
log.Error("Current full block unavailable", "number", *number, "hash", hash)
backoff = true
continue
}
// Seems we have data ready to be frozen, process in usable batches
limit := *number - params.ImmutabilityThreshold
if limit-f.frozen > freezerBatchLimit {
limit = f.frozen + freezerBatchLimit
}
var (
start = time.Now()
first = f.frozen
ancients = make([]common.Hash, 0, limit-f.frozen)
)
for f.frozen < limit {
// Retrieves all the components of the canonical block
hash := ReadCanonicalHash(nfdb, f.frozen)
if hash == (common.Hash{}) {
log.Error("Canonical hash missing, can't freeze", "number", f.frozen)
break
}
header := ReadHeaderRLP(nfdb, hash, f.frozen)
if len(header) == 0 {
log.Error("Block header missing, can't freeze", "number", f.frozen, "hash", hash)
break
}
body := ReadBodyRLP(nfdb, hash, f.frozen)
if len(body) == 0 {
log.Error("Block body missing, can't freeze", "number", f.frozen, "hash", hash)
break
}
receipts := ReadReceiptsRLP(nfdb, hash, f.frozen)
if len(receipts) == 0 {
log.Error("Block receipts missing, can't freeze", "number", f.frozen, "hash", hash)
break
}
td := ReadTdRLP(nfdb, hash, f.frozen)
if len(td) == 0 {
log.Error("Total difficulty missing, can't freeze", "number", f.frozen, "hash", hash)
break
}
log.Trace("Deep froze ancient block", "number", f.frozen, "hash", hash)
// Inject all the components into the relevant data tables
if err := f.AppendAncient(f.frozen, hash[:], header, body, receipts, td); err != nil {
break
}
ancients = append(ancients, hash)
}
// Batch of blocks have been frozen, flush them before wiping from leveldb
if err := f.Sync(); err != nil {
log.Crit("Failed to flush frozen tables", "err", err)
}
// Wipe out all data from the active database
batch := db.NewBatch()
for i := 0; i < len(ancients); i++ {
// Always keep the genesis block in active database
if first+uint64(i) != 0 {
DeleteBlockWithoutNumber(batch, ancients[i], first+uint64(i))
DeleteCanonicalHash(batch, first+uint64(i))
}
}
if err := batch.Write(); err != nil {
log.Crit("Failed to delete frozen canonical blocks", "err", err)
}
batch.Reset()
// Wipe out side chain also.
for number := first; number < f.frozen; number++ {
// Always keep the genesis block in active database
if number != 0 {
for _, hash := range ReadAllHashes(db, number) {
DeleteBlock(batch, hash, number)
}
}
}
if err := batch.Write(); err != nil {
log.Crit("Failed to delete frozen 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,
}
if n := len(ancients); n > 0 {
context = append(context, []interface{}{"hash", ancients[n-1]}...)
}
log.Info("Deep froze chain segment", context...)
// Avoid database thrashing with tiny writes
if f.frozen-first < freezerBatchLimit {
backoff = true
}
}
}
// repair truncates all data tables to the same length.
func (f *freezer) repair() error {
min := uint64(math.MaxUint64)
for _, table := range f.tables {
items := atomic.LoadUint64(&table.items)
if min > items {
min = items
}
}
for _, table := range f.tables {
if err := table.truncate(min); err != nil {
return err
}
}
atomic.StoreUint64(&f.frozen, min)
return nil
}