3 files changed, 15 insertions, 0 deletions
diff --git a/src/db/lib.rs b/src/db/lib.rs
index d96586be..11cae4e3 100644
--- a/src/db/lib.rs
+++ b/src/db/lib.rs
@@ -181,6 +181,10 @@ impl Tree {
 	pub fn len(&self) -> Result<usize> {
 		self.0.len(self.1)
 	}
+	#[inline]
+	pub fn fast_len(&self) -> Result<Option<usize>> {
+		self.0.fast_len(self.1)
+	}
 
 	#[inline]
 	pub fn first(&self) -> Result<Option<(Value, Value)>> {
@@ -323,6 +327,9 @@ pub(crate) trait IDb: Send + Sync {
 
 	fn get(&self, tree: usize, key: &[u8]) -> Result<Option<Value>>;
 	fn len(&self, tree: usize) -> Result<usize>;
+	fn fast_len(&self, _tree: usize) -> Result<Option<usize>> {
+		Ok(None)
+	}
 
 	fn insert(&self, tree: usize, key: &[u8], value: &[u8]) -> Result<Option<Value>>;
 	fn remove(&self, tree: usize, key: &[u8]) -> Result<Option<Value>>;
diff --git a/src/db/lmdb_adapter.rs b/src/db/lmdb_adapter.rs
index c036c990..31956612 100644
--- a/src/db/lmdb_adapter.rs
+++ b/src/db/lmdb_adapter.rs
@@ -121,6 +121,10 @@ impl IDb for LmdbDb {
 		Ok(tree.len(&tx)?.try_into().unwrap())
 	}
 
+	fn fast_len(&self, tree: usize) -> Result<Option<usize>> {
+		Ok(Some(self.len(tree)?))
+	}
+
 	fn insert(&self, tree: usize, key: &[u8], value: &[u8]) -> Result<Option<Value>> {
 		let tree = self.get_tree(tree)?;
 		let mut tx = self.db.write_txn()?;
diff --git a/src/db/sqlite_adapter.rs b/src/db/sqlite_adapter.rs
index 886fda6e..63b4506e 100644
--- a/src/db/sqlite_adapter.rs
+++ b/src/db/sqlite_adapter.rs
@@ -144,6 +144,10 @@ impl IDb for SqliteDb {
 		}
 	}
 
+	fn fast_len(&self, tree: usize) -> Result<Option<usize>> {
+		Ok(Some(self.len(tree)?))
+	}
+
 	fn insert(&self, tree: usize, key: &[u8], value: &[u8]) -> Result<Option<Value>> {
 		trace!("insert {}: lock db", tree);
 		let this = self.0.lock().unwrap();