eth/downloader: dynamically move pivot even during chain sync ethereum#21529

Author: JukLee0ira

core/rawdb/accessors_chain.go

@@ -164,6 +164,17 @@ func WriteFastTrieProgress(db ethdb.KeyValueWriter, count uint64) error {
 	return nil
 }
 
+// WriteLastPivotNumber stores the number of the last pivot block.
+func WriteLastPivotNumber(db ethdb.KeyValueWriter, pivot uint64) {
+	enc, err := rlp.EncodeToBytes(pivot)
+	if err != nil {
+		log.Crit("Failed to encode pivot block number", "err", err)
+	}
+	if err := db.Put(lastPivotKey, enc); err != nil {
+		log.Crit("Failed to store pivot block number", "err", err)
+	}
+}
+
 // ReadHeaderRLP retrieves a block header in its raw RLP database encoding.
 func ReadHeaderRLP(db ethdb.Reader, hash common.Hash, number uint64) rlp.RawValue {
 	// First try to look up the data in ancient database. Extra hash

core/rawdb/schema.go

@@ -39,6 +39,9 @@ var (
 	// headFastBlockKey tracks the latest known incomplete block's hash during fast sync.
 	headFastBlockKey = []byte("LastFast")
 
+	// lastPivotKey tracks the last pivot block used by fast sync (to reenable on sethead).
+	lastPivotKey = []byte("LastPivot")
+
 	// fastTrieProgressKey tracks the number of trie entries imported during fast sync.
 	fastTrieProgressKey = []byte("TrieSync")