diff --git a/workers/proxy_worker/dispatcher.py b/workers/proxy_worker/dispatcher.py
index 55aaeb3b..0276a044 100644
--- a/workers/proxy_worker/dispatcher.py
+++ b/workers/proxy_worker/dispatcher.py
@@ -35,8 +35,22 @@
 from proxy_worker.version import VERSION
 from .utils.dependency import DependencyManager
 
+# Cache protobuf constants to avoid repeated lookups in hot paths
+_RpcLog = protos.RpcLog
+_LOG_LEVEL_CRITICAL = _RpcLog.Critical
+_LOG_LEVEL_ERROR = _RpcLog.Error
+_LOG_LEVEL_WARNING = _RpcLog.Warning
+_LOG_LEVEL_INFO = _RpcLog.Information
+_LOG_LEVEL_DEBUG = _RpcLog.Debug
+_LOG_LEVEL_NONE = getattr(_RpcLog, 'None')
+
+_RpcLogCategory = _RpcLog.RpcLogCategory
+_LOG_CATEGORY_SYSTEM = _RpcLogCategory.Value('System')
+_LOG_CATEGORY_USER = _RpcLogCategory.Value('User')
+
 # Library worker import reloaded in init and reload request
 _library_worker = None
+_library_worker_has_cv = False
 
 # Thread-local invocation ID registry for efficient lookup
 _thread_invocation_registry: typing.Dict[int, str] = {}
@@ -99,9 +113,9 @@ def get_global_current_invocation_id() -> Optional[str]:
 
 
 def get_current_invocation_id() -> Optional[Any]:
-    global _library_worker
+    global _library_worker, _library_worker_has_cv
     # Check global current invocation first (most up-to-date)
-    if _library_worker and not hasattr(_library_worker, 'invocation_id_cv'):
+    if _library_worker and not _library_worker_has_cv:
         global_invocation_id = get_global_current_invocation_id()
         if global_invocation_id is not None:
             return global_invocation_id
@@ -121,23 +135,22 @@ def get_current_invocation_id() -> Optional[Any]:
         # No event loop running
         pass
 
+    # Check contextvar from library worker
+    if _library_worker and _library_worker_has_cv:
+        try:
+            cv = _library_worker.invocation_id_cv
+            val = cv.get()
+            if val is not None:
+                return val
+        except (AttributeError, LookupError):
+            pass
+
     # Check the thread-local invocation ID registry
     current_thread_id = threading.get_ident()
     thread_invocation_id = get_thread_invocation_id(current_thread_id)
     if thread_invocation_id is not None:
         return thread_invocation_id
 
-    # Check contextvar from library worker
-    if _library_worker:
-        try:
-            cv = getattr(_library_worker, 'invocation_id_cv', None)
-            if cv:
-                val = cv.get()
-                if val is not None:
-                    return val
-        except (AttributeError, LookupError):
-            pass
-
     return getattr(_invocation_id_local, 'invocation_id', None)
 
 
@@ -204,22 +217,22 @@ def __init__(self, loop: AbstractEventLoop, host: str, port: int,
     def on_logging(self, record: logging.LogRecord,
                    formatted_msg: str) -> None:
         if record.levelno >= logging.CRITICAL:
-            log_level = protos.RpcLog.Critical
+            log_level = _LOG_LEVEL_CRITICAL
         elif record.levelno >= logging.ERROR:
-            log_level = protos.RpcLog.Error
+            log_level = _LOG_LEVEL_ERROR
         elif record.levelno >= logging.WARNING:
-            log_level = protos.RpcLog.Warning
+            log_level = _LOG_LEVEL_WARNING
         elif record.levelno >= logging.INFO:
-            log_level = protos.RpcLog.Information
+            log_level = _LOG_LEVEL_INFO
         elif record.levelno >= logging.DEBUG:
-            log_level = protos.RpcLog.Debug
+            log_level = _LOG_LEVEL_DEBUG
         else:
-            log_level = getattr(protos.RpcLog, 'None')
+            log_level = _LOG_LEVEL_NONE
 
         if is_system_log_category(record.name):
-            log_category = protos.RpcLog.RpcLogCategory.Value('System')
+            log_category = _LOG_CATEGORY_SYSTEM
         else:  # customers using logging will yield 'root' in record.name
-            log_category = protos.RpcLog.RpcLogCategory.Value('User')
+            log_category = _LOG_CATEGORY_USER
 
         log = dict(
             level=log_level,
@@ -404,12 +417,13 @@ def stop(self) -> None:
 
     @staticmethod
     def reload_library_worker(directory: str):
-        global _library_worker
+        global _library_worker, _library_worker_has_cv
         v2_scriptfile = os.path.join(directory, get_script_file_name())
         if os.path.exists(v2_scriptfile):
             try:
                 import azure_functions_runtime  # NoQA
                 _library_worker = azure_functions_runtime
+                _library_worker_has_cv = hasattr(_library_worker, 'invocation_id_cv')
                 logger.debug("azure_functions_runtime import succeeded: %s",
                              _library_worker.__file__)
             except ImportError:
@@ -419,6 +433,7 @@ def reload_library_worker(directory: str):
             try:
                 import azure_functions_runtime_v1  # NoQA
                 _library_worker = azure_functions_runtime_v1
+                _library_worker_has_cv = hasattr(_library_worker, 'invocation_id_cv')
                 logger.debug("azure_functions_runtime_v1 import succeeded: %s",
                              _library_worker.__file__)  # type: ignore[union-attr]
             except ImportError: