diff --git a/dpsynth/adapters/protobuf.py b/dpsynth/adapters/protobuf.py
index 85fae73a..06389d5f 100644
--- a/dpsynth/adapters/protobuf.py
+++ b/dpsynth/adapters/protobuf.py
@@ -16,8 +16,11 @@
 from __future__ import annotations
 
 from collections.abc import Mapping, Sequence
+import functools
+import operator
 from typing import Any, Literal
 
+from absl import logging
 from dpsynth import domain
 from google.protobuf import descriptor
 from google.protobuf import message
@@ -107,10 +110,12 @@ def infer_domain(
   for field in msg_desc.fields:
     if _is_repeated(field):
       if ignore_unsupported_fields:
+        logging.info("Skipping repeated field %s", field.name)
         continue
       raise ValueError(f"Repeated field '{field.name}' is not supported.")
 
     if field.type == descriptor.FieldDescriptor.TYPE_MESSAGE:
+      # Strip the submessage prefix from numerical_bounds before recursing.
       prefix = f"{field.name}."
       sub_bounds = {
           k.removeprefix(prefix): v
@@ -138,6 +143,7 @@ def infer_domain(
       dtype = "int" if field.type in _INTEGER_TYPES else "float"
       if field.name not in numerical_bounds:
         if ignore_unsupported_fields:
+          logging.info("Skipping numeric field %s", field.name)
           continue
         raise ValueError(
             f"Numerical bounds must be specified for field '{field.name}'."
@@ -154,6 +160,7 @@ def infer_domain(
       )
     else:
       if ignore_unsupported_fields:
+        logging.info("Skipping unsupported field %s", field.name)
         continue
       raise ValueError(
           f"Field '{field.name}' of type {field.type} is not supported."
@@ -179,6 +186,7 @@ def infer_schema(
   return domain.Schema(attributes)
 
 
+@functools.lru_cache(maxsize=64)
 def _leaf_field_paths(desc):
   """Returns dot-separated field paths for all non-repeated leaf fields."""
   paths = []
@@ -190,7 +198,7 @@ def _leaf_field_paths(desc):
       paths.extend(f"{field.name}.{p}" for p in sub_paths)
     else:
       paths.append(field.name)
-  return paths
+  return tuple(paths)
 
 
 def _resolve_leaf(msg, path):
@@ -201,6 +209,30 @@ def _resolve_leaf(msg, path):
   return msg, leaf
 
 
+@functools.lru_cache(maxsize=64)
+def _compile_getters(desc, paths, enum_format):
+  """Precompiles per-field getters for fast tuple extraction."""
+  getters = []
+  for path in paths:
+    # Walk nested message descriptors to inspect the leaf FieldDescriptor.
+    sub_desc = desc
+    *parents, leaf = path.split(".")
+    for part in parents:
+      sub_desc = sub_desc.fields_by_name[part].message_type
+    field = sub_desc.fields_by_name[leaf]
+    # operator.attrgetter resolves dotted paths ("a.b.c") natively in C.
+    getter = operator.attrgetter(path)
+    if (
+        field.type == descriptor.FieldDescriptor.TYPE_ENUM
+        and enum_format == "name"
+    ):
+      # Proto enum attributes return integer wire numbers; map to enum names.
+      names = {v.number: v.name for v in field.enum_type.values}
+      getter = lambda m, g=getter, n=names: n[g(m)]
+    getters.append(getter)
+  return tuple(getters)
+
+
 def to_tuple(
     msg: message.Message,
     *,
@@ -208,19 +240,10 @@ def to_tuple(
     enum_format: Literal["name", "number"] = "name",
 ) -> tuple[Any, ...]:
   """Converts a Protobuf message instance to a tuple of field values."""
-  fields = _leaf_field_paths(msg.DESCRIPTOR) if schema is None else schema
-  result = []
-  for path in fields:
-    sub_msg, leaf = _resolve_leaf(msg, path)
-    field = sub_msg.DESCRIPTOR.fields_by_name[leaf]
-    val = getattr(sub_msg, leaf)
-    if (
-        field.type == descriptor.FieldDescriptor.TYPE_ENUM
-        and enum_format == "name"
-    ):
-      val = field.enum_type.values_by_number[val].name
-    result.append(val)
-  return tuple(result)
+  # Convert schema to a tuple of field names so it is hashable for lru_cache.
+  paths = _leaf_field_paths(msg.DESCRIPTOR) if schema is None else tuple(schema)
+  getters = _compile_getters(msg.DESCRIPTOR, paths, enum_format)
+  return tuple(g(msg) for g in getters)
 
 
 def from_tuple(
@@ -232,6 +255,7 @@ def from_tuple(
   """Populates a Protobuf message from a sequence of field values."""
   desc = _resolve_descriptor(proto)
   fields = _leaf_field_paths(desc) if schema is None else schema
+  # Instantiate an empty message class from the Descriptor and populate leaves.
   msg = message_factory.GetMessageClass(desc)()
   for path, val in zip(fields, values):
     sub_msg, leaf = _resolve_leaf(msg, path)