core, trie: flush preimages to db on database close #25533 (#1107)

core/blockchain.go

@@ -1161,6 +1161,10 @@ func (bc *BlockChain) Stop() {
 	bc.chainmu.Close()
 	bc.wg.Wait()
 	bc.saveData()
+	// Flush the collected preimages to disk
+	if err := bc.stateCache.TrieDB().CommitPreimages(); err != nil {
+		log.Error("Failed to commit trie preimages", "err", err)
+	}
 	log.Info("Blockchain manager stopped")
 }
 

trie/database.go

@@ -824,3 +824,16 @@ func (db *Database) Size() (common.StorageSize, common.StorageSize) {
 	}
 	return db.dirtiesSize + db.childrenSize + metadataSize - metarootRefs, preimageSize
 }
+
+// CommitPreimages flushes the dangling preimages to disk. It is meant to be
+// called when closing the blockchain object, so that preimages are persisted
+// to the database.
+func (db *Database) CommitPreimages() error {
+	db.lock.Lock()
+	defer db.lock.Unlock()
+
+	if db.preimages == nil {
+		return nil
+	}
+	return db.preimages.commit(true)
+}