From 8c8a9e5ca1f7d30cddd91f510dd978d42496d225 Mon Sep 17 00:00:00 2001 From: rjl493456442 Date: Thu, 10 Mar 2022 16:35:22 +0800 Subject: [PATCH] core, ethdb, tests, trie: introduce database snapshot (#24486) --- core/rawdb/table.go | 7 +++ ethdb/database.go | 2 + ethdb/dbtest/testsuite.go | 62 +++++++++++++++++++++++ ethdb/leveldb/leveldb.go | 36 ++++++++++++++ ethdb/memorydb/memorydb.go | 69 +++++++++++++++++++++++++- ethdb/snapshot.go | 41 +++++++++++++++ tests/fuzzers/stacktrie/trie_fuzzer.go | 1 + trie/iterator_test.go | 6 ++- trie/trie_test.go | 1 + 9 files changed, 223 insertions(+), 2 deletions(-) create mode 100644 ethdb/snapshot.go diff --git a/core/rawdb/table.go b/core/rawdb/table.go index bd47161c5f..253ed51455 100644 --- a/core/rawdb/table.go +++ b/core/rawdb/table.go @@ -177,6 +177,13 @@ func (t *table) NewBatchWithSize(size int) ethdb.Batch { return &tableBatch{t.db.NewBatchWithSize(size), t.prefix} } +// NewSnapshot creates a database snapshot based on the current state. +// The created snapshot will not be affected by all following mutations +// happened on the database. +func (t *table) NewSnapshot() (ethdb.Snapshot, error) { + return t.db.NewSnapshot() +} + // tableBatch is a wrapper around a database batch that prefixes each key access // with a pre-configured string. type tableBatch struct { diff --git a/ethdb/database.go b/ethdb/database.go index 0a5729c6c1..1057636762 100644 --- a/ethdb/database.go +++ b/ethdb/database.go @@ -64,6 +64,7 @@ type KeyValueStore interface { Iteratee Stater Compacter + Snapshotter io.Closer } @@ -153,5 +154,6 @@ type Database interface { Iteratee Stater Compacter + Snapshotter io.Closer } diff --git a/ethdb/dbtest/testsuite.go b/ethdb/dbtest/testsuite.go index 06ee2211e6..6b206af48d 100644 --- a/ethdb/dbtest/testsuite.go +++ b/ethdb/dbtest/testsuite.go @@ -313,6 +313,68 @@ func TestDatabaseSuite(t *testing.T, New func() ethdb.KeyValueStore) { } }) + t.Run("Snapshot", func(t *testing.T) { + db := New() + defer db.Close() + + initial := map[string]string{ + "k1": "v1", "k2": "v2", "k3": "", "k4": "", + } + for k, v := range initial { + db.Put([]byte(k), []byte(v)) + } + snapshot, err := db.NewSnapshot() + if err != nil { + t.Fatal(err) + } + for k, v := range initial { + got, err := snapshot.Get([]byte(k)) + if err != nil { + t.Fatal(err) + } + if !bytes.Equal(got, []byte(v)) { + t.Fatalf("Unexpected value want: %v, got %v", v, got) + } + } + + // Flush more modifications into the database, ensure the snapshot + // isn't affected. + var ( + update = map[string]string{"k1": "v1-b", "k3": "v3-b"} + insert = map[string]string{"k5": "v5-b"} + delete = map[string]string{"k2": ""} + ) + for k, v := range update { + db.Put([]byte(k), []byte(v)) + } + for k, v := range insert { + db.Put([]byte(k), []byte(v)) + } + for k := range delete { + db.Delete([]byte(k)) + } + for k, v := range initial { + got, err := snapshot.Get([]byte(k)) + if err != nil { + t.Fatal(err) + } + if !bytes.Equal(got, []byte(v)) { + t.Fatalf("Unexpected value want: %v, got %v", v, got) + } + } + for k := range insert { + got, err := snapshot.Get([]byte(k)) + if err == nil || len(got) != 0 { + t.Fatal("Unexpected value") + } + } + for k := range delete { + got, err := snapshot.Get([]byte(k)) + if err != nil || len(got) == 0 { + t.Fatal("Unexpected deletion") + } + } + }) } func iterateKeys(it ethdb.Iterator) []string { diff --git a/ethdb/leveldb/leveldb.go b/ethdb/leveldb/leveldb.go index cb348ea28c..15bd4e6eb3 100644 --- a/ethdb/leveldb/leveldb.go +++ b/ethdb/leveldb/leveldb.go @@ -228,6 +228,19 @@ func (db *Database) NewIterator(prefix []byte, start []byte) ethdb.Iterator { return db.db.NewIterator(bytesPrefixRange(prefix, start), nil) } +// NewSnapshot creates a database snapshot based on the current state. +// The created snapshot will not be affected by all following mutations +// happened on the database. +// Note don't forget to release the snapshot once it's used up, otherwise +// the stale data will never be cleaned up by the underlying compactor. +func (db *Database) NewSnapshot() (ethdb.Snapshot, error) { + snap, err := db.db.GetSnapshot() + if err != nil { + return nil, err + } + return &snapshot{db: snap}, nil +} + // Stat returns a particular internal stat of the database. func (db *Database) Stat(property string) (string, error) { return db.db.GetProperty(property) @@ -527,3 +540,26 @@ func bytesPrefixRange(prefix, start []byte) *util.Range { r.Start = append(r.Start, start...) return r } + +// snapshot wraps a leveldb snapshot for implementing the Snapshot interface. +type snapshot struct { + db *leveldb.Snapshot +} + +// Has retrieves if a key is present in the snapshot backing by a key-value +// data store. +func (snap *snapshot) Has(key []byte) (bool, error) { + return snap.db.Has(key, nil) +} + +// Get retrieves the given key if it's present in the snapshot backing by +// key-value data store. +func (snap *snapshot) Get(key []byte) ([]byte, error) { + return snap.db.Get(key, nil) +} + +// Release releases associated resources. Release should always succeed and can +// be called multiple times without causing error. +func (snap *snapshot) Release() { + snap.db.Release() +} diff --git a/ethdb/memorydb/memorydb.go b/ethdb/memorydb/memorydb.go index 7c8d655f4a..95ec9bb8aa 100644 --- a/ethdb/memorydb/memorydb.go +++ b/ethdb/memorydb/memorydb.go @@ -35,6 +35,10 @@ var ( // errMemorydbNotFound is returned if a key is requested that is not found in // the provided memory database. errMemorydbNotFound = errors.New("not found") + + // errSnapshotReleased is returned if callers want to retrieve data from a + // released snapshot. + errSnapshotReleased = errors.New("snapshot released") ) // Database is an ephemeral key-value store. Apart from basic data storage @@ -53,7 +57,7 @@ func New() *Database { } } -// NewWithCap returns a wrapped map pre-allocated to the provided capcity with +// NewWithCap returns a wrapped map pre-allocated to the provided capacity with // all the required database interface methods implemented. func NewWithCap(size int) *Database { return &Database{ @@ -170,6 +174,13 @@ func (db *Database) NewIterator(prefix []byte, start []byte) ethdb.Iterator { } } +// NewSnapshot creates a database snapshot based on the current state. +// The created snapshot will not be affected by all following mutations +// happened on the database. +func (db *Database) NewSnapshot() (ethdb.Snapshot, error) { + return newSnapshot(db), nil +} + // Stat returns a particular internal stat of the database. func (db *Database) Stat(property string) (string, error) { return "", errors.New("unknown property") @@ -320,3 +331,59 @@ func (it *iterator) Value() []byte { func (it *iterator) Release() { it.keys, it.values = nil, nil } + +// snapshot wraps a batch of key-value entries deep copied from the in-memory +// database for implementing the Snapshot interface. +type snapshot struct { + db map[string][]byte + lock sync.RWMutex +} + +// newSnapshot initializes the snapshot with the given database instance. +func newSnapshot(db *Database) *snapshot { + db.lock.RLock() + defer db.lock.RUnlock() + + copied := make(map[string][]byte) + for key, val := range db.db { + copied[key] = common.CopyBytes(val) + } + return &snapshot{db: copied} +} + +// Has retrieves if a key is present in the snapshot backing by a key-value +// data store. +func (snap *snapshot) Has(key []byte) (bool, error) { + snap.lock.RLock() + defer snap.lock.RUnlock() + + if snap.db == nil { + return false, errSnapshotReleased + } + _, ok := snap.db[string(key)] + return ok, nil +} + +// Get retrieves the given key if it's present in the snapshot backing by +// key-value data store. +func (snap *snapshot) Get(key []byte) ([]byte, error) { + snap.lock.RLock() + defer snap.lock.RUnlock() + + if snap.db == nil { + return nil, errSnapshotReleased + } + if entry, ok := snap.db[string(key)]; ok { + return common.CopyBytes(entry), nil + } + return nil, errMemorydbNotFound +} + +// Release releases associated resources. Release should always succeed and can +// be called multiple times without causing error. +func (snap *snapshot) Release() { + snap.lock.Lock() + defer snap.lock.Unlock() + + snap.db = nil +} diff --git a/ethdb/snapshot.go b/ethdb/snapshot.go new file mode 100644 index 0000000000..753e0f6b1f --- /dev/null +++ b/ethdb/snapshot.go @@ -0,0 +1,41 @@ +// Copyright 2018 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 . + +package ethdb + +type Snapshot interface { + // Has retrieves if a key is present in the snapshot backing by a key-value + // data store. + Has(key []byte) (bool, error) + + // Get retrieves the given key if it's present in the snapshot backing by + // key-value data store. + Get(key []byte) ([]byte, error) + + // Release releases associated resources. Release should always succeed and can + // be called multiple times without causing error. + Release() +} + +// Snapshotter wraps the Snapshot method of a backing data store. +type Snapshotter interface { + // NewSnapshot creates a database snapshot based on the current state. + // The created snapshot will not be affected by all following mutations + // happened on the database. + // Note don't forget to release the snapshot once it's used up, otherwise + // the stale data will never be cleaned up by the underlying compactor. + NewSnapshot() (Snapshot, error) +} diff --git a/tests/fuzzers/stacktrie/trie_fuzzer.go b/tests/fuzzers/stacktrie/trie_fuzzer.go index 6beec7c802..9ed8bcbc51 100644 --- a/tests/fuzzers/stacktrie/trie_fuzzer.go +++ b/tests/fuzzers/stacktrie/trie_fuzzer.go @@ -67,6 +67,7 @@ func (s *spongeDb) Get(key []byte) ([]byte, error) { return nil, error func (s *spongeDb) Delete(key []byte) error { panic("implement me") } func (s *spongeDb) NewBatch() ethdb.Batch { return &spongeBatch{s} } func (s *spongeDb) NewBatchWithSize(size int) ethdb.Batch { return &spongeBatch{s} } +func (s *spongeDb) NewSnapshot() (ethdb.Snapshot, error) { panic("implement me") } func (s *spongeDb) Stat(property string) (string, error) { panic("implement me") } func (s *spongeDb) Compact(start []byte, limit []byte) error { panic("implement me") } func (s *spongeDb) Close() error { return nil } diff --git a/trie/iterator_test.go b/trie/iterator_test.go index fdcb8f3843..1a9a5e80e5 100644 --- a/trie/iterator_test.go +++ b/trie/iterator_test.go @@ -475,9 +475,13 @@ func (l *loggingDb) NewBatchWithSize(size int) ethdb.Batch { } func (l *loggingDb) NewIterator(prefix []byte, start []byte) ethdb.Iterator { - fmt.Printf("NewIterator\n") return l.backend.NewIterator(prefix, start) } + +func (l *loggingDb) NewSnapshot() (ethdb.Snapshot, error) { + return l.backend.NewSnapshot() +} + func (l *loggingDb) Stat(property string) (string, error) { return l.backend.Stat(property) } diff --git a/trie/trie_test.go b/trie/trie_test.go index 63aed333db..a1fdc8cd58 100644 --- a/trie/trie_test.go +++ b/trie/trie_test.go @@ -677,6 +677,7 @@ func (s *spongeDb) Get(key []byte) ([]byte, error) { return nil, error func (s *spongeDb) Delete(key []byte) error { panic("implement me") } func (s *spongeDb) NewBatch() ethdb.Batch { return &spongeBatch{s} } func (s *spongeDb) NewBatchWithSize(size int) ethdb.Batch { return &spongeBatch{s} } +func (s *spongeDb) NewSnapshot() (ethdb.Snapshot, error) { panic("implement me") } func (s *spongeDb) Stat(property string) (string, error) { panic("implement me") } func (s *spongeDb) Compact(start []byte, limit []byte) error { panic("implement me") } func (s *spongeDb) Close() error { return nil }