Official Go implementation of the Ethereum protocol
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go-ethereum/core/state/snapshot/wipe.go

132 lines
4.4 KiB

// 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 snapshot
import (
"bytes"
"time"
"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"
)
// wipeSnapshot starts a goroutine to iterate over the entire key-value database
// and delete all the data associated with the snapshot (accounts, storage,
// metadata). After all is done, the snapshot range of the database is compacted
// to free up unused data blocks.
func wipeSnapshot(db ethdb.KeyValueStore, full bool) chan struct{} {
// Wipe the snapshot root marker synchronously
if full {
rawdb.DeleteSnapshotRoot(db)
}
// Wipe everything else asynchronously
wiper := make(chan struct{}, 1)
go func() {
if err := wipeContent(db); err != nil {
log.Error("Failed to wipe state snapshot", "err", err) // Database close will trigger this
return
}
close(wiper)
}()
return wiper
}
// wipeContent iterates over the entire key-value database and deletes all the
// data associated with the snapshot (accounts, storage), but not the root hash
// as the wiper is meant to run on a background thread but the root needs to be
// removed in sync to avoid data races. After all is done, the snapshot range of
// the database is compacted to free up unused data blocks.
func wipeContent(db ethdb.KeyValueStore) error {
if err := wipeKeyRange(db, "accounts", rawdb.SnapshotAccountPrefix, len(rawdb.SnapshotAccountPrefix)+common.HashLength); err != nil {
return err
}
if err := wipeKeyRange(db, "storage", rawdb.SnapshotStoragePrefix, len(rawdb.SnapshotStoragePrefix)+2*common.HashLength); err != nil {
return err
}
// Compact the snapshot section of the database to get rid of unused space
start := time.Now()
log.Info("Compacting snapshot account area ")
end := common.CopyBytes(rawdb.SnapshotAccountPrefix)
end[len(end)-1]++
if err := db.Compact(rawdb.SnapshotAccountPrefix, end); err != nil {
return err
}
log.Info("Compacting snapshot storage area ")
end = common.CopyBytes(rawdb.SnapshotStoragePrefix)
end[len(end)-1]++
if err := db.Compact(rawdb.SnapshotStoragePrefix, end); err != nil {
return err
}
log.Info("Compacted snapshot area in database", "elapsed", common.PrettyDuration(time.Since(start)))
return nil
}
// wipeKeyRange deletes a range of keys from the database starting with prefix
// and having a specific total key length.
func wipeKeyRange(db ethdb.KeyValueStore, kind string, prefix []byte, keylen int) error {
// Batch deletions together to avoid holding an iterator for too long
var (
batch = db.NewBatch()
items int
)
// Iterate over the key-range and delete all of them
start, logged := time.Now(), time.Now()
it := db.NewIterator(prefix, nil)
for it.Next() {
// Skip any keys with the correct prefix but wrong length (trie nodes)
key := it.Key()
if !bytes.HasPrefix(key, prefix) {
break
}
if len(key) != keylen {
continue
}
// Delete the key and periodically recreate the batch and iterator
batch.Delete(key)
items++
if items%10000 == 0 {
// Batch too large (or iterator too long lived, flush and recreate)
it.Release()
if err := batch.Write(); err != nil {
return err
}
batch.Reset()
seekPos := key[len(prefix):]
it = db.NewIterator(prefix, seekPos)
if time.Since(logged) > 8*time.Second {
log.Info("Deleting state snapshot leftovers", "kind", kind, "wiped", items, "elapsed", common.PrettyDuration(time.Since(start)))
logged = time.Now()
}
}
}
it.Release()
if err := batch.Write(); err != nil {
return err
}
log.Info("Deleted state snapshot leftovers", "kind", kind, "wiped", items, "elapsed", common.PrettyDuration(time.Since(start)))
return nil
}