From d383d70763fb89338a4a9a3095015123a5915130 Mon Sep 17 00:00:00 2001
From: lxc <ppdoooog@gmail.com>
Date: Mon, 5 May 2025 17:38:02 +0800
Subject: [PATCH] Update watermark.rs (#144)

add function that tests require
---
 mini-lsm-starter/src/mvcc/watermark.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/mini-lsm-starter/src/mvcc/watermark.rs b/mini-lsm-starter/src/mvcc/watermark.rs
index e4d80ad..34b016f 100644
--- a/mini-lsm-starter/src/mvcc/watermark.rs
+++ b/mini-lsm-starter/src/mvcc/watermark.rs
@@ -32,6 +32,10 @@ impl Watermark {
 
     pub fn remove_reader(&mut self, ts: u64) {}
 
+    pub fn num_retained_snapshots(&self) -> usize {
+        0
+    }
+
     pub fn watermark(&self) -> Option<u64> {
         Some(0)
     }