// 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/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/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
}
// 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)
sizeCounter = metrics.NewRegisteredCounter(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,
}
for name, disableSnappy := range freezerNoSnappy {
table, err := newTable(datadir, name, readMeter, writeMeter, sizeCounter, 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 {
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}
for {
// 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)
continue
}
number := ReadHeaderNumber(nfdb, hash)
switch {
case number == nil:
log.Error("Current full block number unavailable", "hash", hash)
time.Sleep(freezerRecheckInterval)
continue
case *number < params.ImmutabilityThreshold:
log.Debug("Current full block not old enough", "number", *number, "hash", hash, "delay", params.ImmutabilityThreshold)
time.Sleep(freezerRecheckInterval)
continue
case *number-params.ImmutabilityThreshold <= f.frozen:
log.Debug("Ancient blocks frozen already", "number", *number, "hash", hash, "frozen", f.frozen)
time.Sleep(freezerRecheckInterval)
continue
}
head := ReadHeader(nfdb, hash, *number)
if head == nil {
log.Error("Current full block unavailable", "number", *number, "hash", hash)
time.Sleep(freezerRecheckInterval)
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)
)
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 {
time.Sleep(freezerRecheckInterval)
}
}
}
// 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
}