diff --git a/channeldb/db.go b/channeldb/db.go
index fed6dfa0..eace4997 100644
--- a/channeldb/db.go
+++ b/channeldb/db.go
@@ -114,7 +114,7 @@ type DB struct {
 
 // Open opens an existing channeldb. Any necessary schemas migrations due to
 // updates will take place as necessary.
-func Open(dbPath string) (*DB, error) {
+func Open(dbPath string, modifiers ...OptionModifier) (*DB, error) {
 	path := filepath.Join(dbPath, dbName)
 
 	if !fileExists(path) {
@@ -123,6 +123,11 @@ func Open(dbPath string) (*DB, error) {
 		}
 	}
 
+	opts := DefaultOptions()
+	for _, modifier := range modifiers {
+		modifier(&opts)
+	}
+
 	bdb, err := bbolt.Open(path, dbFilePermission, nil)
 	if err != nil {
 		return nil, err
@@ -132,7 +137,9 @@ func Open(dbPath string) (*DB, error) {
 		DB:     bdb,
 		dbPath: dbPath,
 	}
-	chanDB.graph = newChannelGraph(chanDB)
+	chanDB.graph = newChannelGraph(
+		chanDB, opts.RejectCacheSize, opts.ChannelCacheSize,
+	)
 
 	// Synchronize the version of database and apply migrations if needed.
 	if err := chanDB.syncVersions(dbVersions); err != nil {
diff --git a/channeldb/graph.go b/channeldb/graph.go
index 207e332e..4815a647 100644
--- a/channeldb/graph.go
+++ b/channeldb/graph.go
@@ -165,11 +165,11 @@ type ChannelGraph struct {
 
 // newChannelGraph allocates a new ChannelGraph backed by a DB instance. The
 // returned instance has its own unique reject cache and channel cache.
-func newChannelGraph(db *DB) *ChannelGraph {
+func newChannelGraph(db *DB, rejectCacheSize, chanCacheSize int) *ChannelGraph {
 	return &ChannelGraph{
 		db:          db,
-		rejectCache: newRejectCache(50000),
-		chanCache:   newChannelCache(20000),
+		rejectCache: newRejectCache(rejectCacheSize),
+		chanCache:   newChannelCache(chanCacheSize),
 	}
 }