From 7a9d9c79d15dfa7c2c1ff9685ea7fba3d5c599ad Mon Sep 17 00:00:00 2001
From: fatSheep <50252876+00fish0@users.noreply.github.com>
Date: Tue, 3 Feb 2026 14:54:56 +0800
Subject: [PATCH] [HiCache] fix: apply extra_backend_tag in Mooncake
 batch_exists (#17265)

---
 .../srt/mem_cache/storage/mooncake_store/mooncake_store.py   | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/python/sglang/srt/mem_cache/storage/mooncake_store/mooncake_store.py b/python/sglang/srt/mem_cache/storage/mooncake_store/mooncake_store.py
index 5c3b3d1ce..f661e73fa 100644
--- a/python/sglang/srt/mem_cache/storage/mooncake_store/mooncake_store.py
+++ b/python/sglang/srt/mem_cache/storage/mooncake_store/mooncake_store.py
@@ -649,6 +649,11 @@ class MooncakeStore(HiCacheStorage):
     def batch_exists(
         self, keys, extra_info: Optional[HiCacheStorageExtraInfo] = None
     ) -> int:
+        # Apply extra_backend_tag prefix if available
+        if self.extra_backend_tag is not None:
+            prefix = self.extra_backend_tag
+            keys = [f"{prefix}_{key}" for key in keys]
+
         if self.is_mla_backend:
             query_keys = [f"{key}_{self.mla_suffix}_k" for key in keys]
             key_multiplier = 1