core, ethdb, trie: mode dirty data to clean cache on flush (#19307)

This PR is a more advanced form of the dirty-to-clean cacher (#18995),
where we reuse previous database write batches as datasets to uncache,
saving a dirty-trie-iteration and a dirty-trie-rlp-reencoding per block.

ethdb/batch.go

@@ -24,7 +24,6 @@ const IdealBatchSize = 100 * 1024
 // when Write is called. A batch cannot be used concurrently.
 type Batch interface {
 	Writer
-	Deleter
 
 	// ValueSize retrieves the amount of data queued up for writing.
 	ValueSize() int
@@ -32,8 +31,11 @@ type Batch interface {
 	// Write flushes any accumulated data to disk.
 	Write() error
 
-	// Reset resets the batch for reuse
+	// Reset resets the batch for reuse.
 	Reset()
+
+	// Replay replays the batch contents.
+	Replay(w Writer) error
 }
 
 // Batcher wraps the NewBatch method of a backing data store.

ethdb/database.go

@@ -14,7 +14,7 @@
 // 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 database defines the interfaces for an Ethereum data store.
+// Package ethdb defines the interfaces for an Ethereum data store.
 package ethdb
 
 import "io"
@@ -32,10 +32,7 @@ type Reader interface {
 type Writer interface {
 	// Put inserts the given value into the key-value data store.
 	Put(key []byte, value []byte) error
-}
 
-// Deleter wraps the Delete method of a backing data store.
-type Deleter interface {
 	// Delete removes the key from the key-value data store.
 	Delete(key []byte) error
 }
@@ -63,7 +60,6 @@ type Compacter interface {
 type KeyValueStore interface {
 	Reader
 	Writer
-	Deleter
 	Batcher
 	Iteratee
 	Stater
@@ -76,7 +72,6 @@ type KeyValueStore interface {
 type Database interface {
 	Reader
 	Writer
-	Deleter
 	Batcher
 	Iteratee
 	Stater

ethdb/leveldb/leveldb.go

@@ -416,3 +416,32 @@ func (b *batch) Reset() {
 	b.b.Reset()
 	b.size = 0
 }
+
+// Replay replays the batch contents.
+func (b *batch) Replay(w ethdb.Writer) error {
+	return b.b.Replay(&replayer{writer: w})
+}
+
+// replayer is a small wrapper to implement the correct replay methods.
+type replayer struct {
+	writer  ethdb.Writer
+	failure error
+}
+
+// Put inserts the given value into the key-value data store.
+func (r *replayer) Put(key, value []byte) {
+	// If the replay already failed, stop executing ops
+	if r.failure != nil {
+		return
+	}
+	r.failure = r.writer.Put(key, value)
+}
+
+// Delete removes the key from the key-value data store.
+func (r *replayer) Delete(key []byte) {
+	// If the replay already failed, stop executing ops
+	if r.failure != nil {
+		return
+	}
+	r.failure = r.writer.Delete(key)
+}

ethdb/memorydb/memorydb.go

@@ -240,6 +240,22 @@ func (b *batch) Reset() {
 	b.size = 0
 }
 
+// Replay replays the batch contents.
+func (b *batch) Replay(w ethdb.Writer) error {
+	for _, keyvalue := range b.writes {
+		if keyvalue.delete {
+			if err := w.Delete(keyvalue.key); err != nil {
+				return err
+			}
+			continue
+		}
+		if err := w.Put(keyvalue.key, keyvalue.value); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 // iterator can walk over the (potentially partial) keyspace of a memory key
 // value store. Internally it is a deep copy of the entire iterated state,
 // sorted by keys.