fix bench db wipe (#6965)

client/db/src/bench.rs

@@ -178,6 +178,7 @@ impl<B: BlockT> BenchmarkingState<B> {
 
 	fn wipe_tracker(&self) {
 		*self.main_key_tracker.borrow_mut() = HashMap::new();
+		*self.child_key_tracker.borrow_mut() = HashMap::new();
 		self.add_whitelist_to_tracker();
 		*self.read_write_tracker.borrow_mut() = Default::default();
 	}
@@ -512,32 +513,36 @@ mod test {
 		let bench_state = BenchmarkingState::<crate::tests::Block>::new(Default::default(), None)
 			.unwrap();
 
-		let child1 = sp_core::storage::ChildInfo::new_default(b"child1");
-		let child2 = sp_core::storage::ChildInfo::new_default(b"child2");
-
-		bench_state.storage(b"foo").unwrap();
-		bench_state.child_storage(&child1, b"foo").unwrap();
-		bench_state.child_storage(&child2, b"foo").unwrap();
-
-		bench_state.storage(b"bar").unwrap();
-		bench_state.child_storage(&child1, b"bar").unwrap();
-		bench_state.child_storage(&child2, b"bar").unwrap();
-
-		bench_state.commit(
-			Default::default(),
-			Default::default(),
-			vec![
-				("foo".as_bytes().to_vec(), None)
-			],
-			vec![
-				("child1".as_bytes().to_vec(), vec![("foo".as_bytes().to_vec(), None)])
-			]
-		).unwrap();
-
-		let rw_tracker = bench_state.read_write_tracker.borrow();
-		assert_eq!(rw_tracker.reads, 6);
-		assert_eq!(rw_tracker.repeat_reads, 0);
-		assert_eq!(rw_tracker.writes, 2);
-		assert_eq!(rw_tracker.repeat_writes, 0);
+		for _ in 0..2 {
+			let child1 = sp_core::storage::ChildInfo::new_default(b"child1");
+			let child2 = sp_core::storage::ChildInfo::new_default(b"child2");
+
+			bench_state.storage(b"foo").unwrap();
+			bench_state.child_storage(&child1, b"foo").unwrap();
+			bench_state.child_storage(&child2, b"foo").unwrap();
+
+			bench_state.storage(b"bar").unwrap();
+			bench_state.child_storage(&child1, b"bar").unwrap();
+			bench_state.child_storage(&child2, b"bar").unwrap();
+
+			bench_state.commit(
+				Default::default(),
+				Default::default(),
+				vec![
+					("foo".as_bytes().to_vec(), None)
+				],
+				vec![
+					("child1".as_bytes().to_vec(), vec![("foo".as_bytes().to_vec(), None)])
+				]
+			).unwrap();
+
+			let rw_tracker = bench_state.read_write_tracker.borrow();
+			assert_eq!(rw_tracker.reads, 6);
+			assert_eq!(rw_tracker.repeat_reads, 0);
+			assert_eq!(rw_tracker.writes, 2);
+			assert_eq!(rw_tracker.repeat_writes, 0);
+			drop(rw_tracker);
+			bench_state.wipe().unwrap();
+		}
 	}
 }