diff --git a/src/common/filter/FunctionManager.cpp b/src/common/filter/FunctionManager.cpp
index 5c9a15b5671..3aeee4c748f 100644
--- a/src/common/filter/FunctionManager.cpp
+++ b/src/common/filter/FunctionManager.cpp
@@ -566,7 +566,6 @@ FunctionManager::get(const std::string &func, size_t arity) {
 StatusOr<FunctionManager::Function>
 FunctionManager::getInternal(const std::string &func, size_t arity) const {
     auto status = Status::OK();
-    folly::RWSpinLock::ReadHolder holder(lock_);
     // check existence
     auto iter = functions_.find(func);
     if (iter == functions_.end()) {
diff --git a/src/common/filter/FunctionManager.h b/src/common/filter/FunctionManager.h
index 2be38b0733f..3d0b8a31ab7 100644
--- a/src/common/filter/FunctionManager.h
+++ b/src/common/filter/FunctionManager.h
@@ -60,7 +60,6 @@ class FunctionManager final {
         Function                body_;
     };
 
-    mutable folly::RWSpinLock                           lock_;
     std::unordered_map<std::string, FunctionAttributes> functions_;
 };