diff --git a/sdk/python/feast/infra/online_stores/milvus_online_store/milvus.py b/sdk/python/feast/infra/online_stores/milvus_online_store/milvus.py
index ee2534684cc..e33765c1ecf 100644
--- a/sdk/python/feast/infra/online_stores/milvus_online_store/milvus.py
+++ b/sdk/python/feast/infra/online_stores/milvus_online_store/milvus.py
@@ -1,4 +1,5 @@
 import base64
+import logging
 from datetime import datetime
 from pathlib import Path
 from typing import Any, Callable, Dict, List, Literal, Optional, Sequence, Tuple, Union
@@ -42,6 +43,8 @@
     to_naive_utc,
 )
 
+logger = logging.getLogger(__name__)
+
 PROTO_TO_MILVUS_TYPE_MAPPING: Dict[ValueType, DataType] = {
     PROTO_VALUE_TO_VALUE_TYPE_MAP["bytes_val"]: DataType.VARCHAR,
     ValueType.IMAGE_BYTES: DataType.VARCHAR,
@@ -140,11 +143,13 @@ def _connect(self, config: RepoConfig) -> MilvusClient:
         if not self.client:
             if config.provider == "local" and config.online_store.path:
                 db_path = self._get_db_path(config)
-                print(f"Connecting to Milvus in local mode using {db_path}")
+                logger.info("Connecting to Milvus in local mode using %s", db_path)
                 self.client = MilvusClient(db_path)
             else:
-                print(
-                    f"Connecting to Milvus remotely at {config.online_store.host}:{config.online_store.port}"
+                logger.info(
+                    "Connecting to Milvus remotely at %s:%s",
+                    config.online_store.host,
+                    config.online_store.port,
                 )
                 self.client = MilvusClient(
                     uri=f"{config.online_store.host}:{config.online_store.port}",
@@ -339,7 +344,6 @@ def online_read(
         table: FeatureView,
         entity_keys: List[EntityKeyProto],
         requested_features: Optional[List[str]] = None,
-        full_feature_names: bool = False,
     ) -> List[Tuple[Optional[datetime], Optional[Dict[str, ValueProto]]]]:
         self.client = self._connect(config)
         collection_name = _table_id(config.project, table)
@@ -487,7 +491,7 @@ def update(
     ):
         self.client = self._connect(config)
         for table in tables_to_keep:
-            self._collections = self._get_or_create_collection(config, table)
+            self._get_or_create_collection(config, table)
 
         for table in tables_to_delete:
             collection_name = _table_id(config.project, table)
@@ -498,7 +502,7 @@ def update(
     def plan(
         self, config: RepoConfig, desired_registry_proto: RegistryProto
     ) -> List[InfraObject]:
-        raise NotImplementedError
+        return []
 
     def teardown(
         self,
@@ -686,9 +690,8 @@ def retrieve_online_documents_v2(
             for hit in hits:
                 res = {}
                 res_ts = None
-                entity_key_bytes = bytes.fromhex(
-                    hit.get("entity", {}).get(composite_key_name, None)
-                )
+                raw_key = hit.get("entity", {}).get(composite_key_name)
+                entity_key_bytes = bytes.fromhex(raw_key) if raw_key else None
                 entity_key_proto = (
                     deserialize_entity_key(entity_key_bytes)
                     if entity_key_bytes
diff --git a/sdk/python/tests/unit/online_store/test_online_retrieval.py b/sdk/python/tests/unit/online_store/test_online_retrieval.py
index 60f583ad669..63dcc8c7e48 100644
--- a/sdk/python/tests/unit/online_store/test_online_retrieval.py
+++ b/sdk/python/tests/unit/online_store/test_online_retrieval.py
@@ -1714,3 +1714,181 @@ def test_milvus_keyword_search() -> None:
         assert len(result_hybrid["content"]) > 0
         assert any("Feast" in content for content in result_hybrid["content"])
         assert len(result_hybrid["vector"]) > 0
+
+
+def test_milvus_update_preserves_collection_cache() -> None:
+    """
+    Regression test: update() used to overwrite self._collections with the
+    describe_collection() dict of the last processed table, replacing the
+    dict-of-dicts cache with a single flat dict.  After the fix, each call
+    to _get_or_create_collection() updates the keyed entry in-place and the
+    cache remains a proper mapping from collection name to collection info.
+    """
+    from datetime import timedelta
+
+    from feast import Entity, FeatureView, Field, FileSource
+    from feast.types import Array, Float32, Int64, String
+
+    runner = CliRunner()
+    with runner.local_repo(
+        example_repo_py=get_example_repo("example_rag_feature_repo.py"),
+        offline_store="file",
+        online_store="milvus",
+        apply=False,
+        teardown=False,
+    ) as store:
+        source = FileSource(
+            path="data/dummy.parquet",
+            timestamp_field="event_timestamp",
+            created_timestamp_column="created_timestamp",
+        )
+        entity_a = Entity(name="id_a", join_keys=["id_a"], value_type=ValueType.INT64)
+        entity_b = Entity(name="id_b", join_keys=["id_b"], value_type=ValueType.INT64)
+
+        fv_a = FeatureView(
+            name="fv_a",
+            entities=[entity_a],
+            schema=[
+                Field(name="id_a", dtype=Int64),
+                Field(
+                    name="vec_a",
+                    dtype=Array(Float32),
+                    vector_index=True,
+                    vector_search_metric="COSINE",
+                ),
+                Field(name="text_a", dtype=String),
+            ],
+            source=source,
+            ttl=timedelta(hours=1),
+        )
+        fv_b = FeatureView(
+            name="fv_b",
+            entities=[entity_b],
+            schema=[
+                Field(name="id_b", dtype=Int64),
+                Field(
+                    name="vec_b",
+                    dtype=Array(Float32),
+                    vector_index=True,
+                    vector_search_metric="COSINE",
+                ),
+                Field(name="text_b", dtype=String),
+            ],
+            source=source,
+            ttl=timedelta(hours=1),
+        )
+
+        store.apply([source, entity_a, entity_b, fv_a, fv_b])
+
+        online_store = store._provider._online_store
+        # After applying two feature views, the cache must be a proper dict
+        # mapping collection names to collection-info dicts, not a flat dict.
+        assert isinstance(online_store._collections, dict), (
+            "_collections should be a dict"
+        )
+        collection_name_a = f"{store.config.project}_fv_a"
+        collection_name_b = f"{store.config.project}_fv_b"
+        assert collection_name_a in online_store._collections, (
+            f"Cache missing entry for {collection_name_a}"
+        )
+        assert collection_name_b in online_store._collections, (
+            f"Cache missing entry for {collection_name_b} — "
+            "update() likely overwrote _collections with a single collection dict"
+        )
+        # Each cached value must be a collection-info dict (has a 'fields' key),
+        # not itself keyed by collection name.
+        for name in [collection_name_a, collection_name_b]:
+            assert "fields" in online_store._collections[name], (
+                f"Cache entry for {name} looks like a corrupted flat dict"
+            )
+
+
+def test_milvus_plan_returns_empty_list() -> None:
+    """
+    Regression test: plan() used to raise NotImplementedError, causing
+    `feast plan` to crash for any project using the Milvus online store.
+    It should return [] matching the OnlineStore base class default.
+    """
+    from feast.infra.online_stores.milvus_online_store.milvus import MilvusOnlineStore
+
+    store = MilvusOnlineStore()
+    result = store.plan(config=None, desired_registry_proto=None)  # type: ignore[arg-type]
+    assert result == [], f"plan() should return [] but returned {result!r}"
+
+
+def test_milvus_retrieve_online_documents_v2_missing_entity_key() -> None:
+    """
+    Regression test: retrieve_online_documents_v2() passed the raw
+    hit.get("entity", {}).get(composite_key_name, None) directly to
+    bytes.fromhex(), raising TypeError when the key was absent.
+    After the fix, a missing composite key produces a None entity_key_proto
+    instead of crashing.
+    """
+    from datetime import timedelta
+    from unittest.mock import patch
+
+    from feast import Entity, FeatureView, Field, FileSource
+    from feast.types import Array, Float32, Int64, String
+
+    runner = CliRunner()
+    with runner.local_repo(
+        example_repo_py=get_example_repo("example_rag_feature_repo.py"),
+        offline_store="file",
+        online_store="milvus",
+        apply=False,
+        teardown=False,
+    ) as store:
+        source = FileSource(
+            path="data/dummy.parquet",
+            timestamp_field="event_timestamp",
+            created_timestamp_column="created_timestamp",
+        )
+        entity = Entity(name="doc_id", join_keys=["doc_id"], value_type=ValueType.INT64)
+        fv = FeatureView(
+            name="docs",
+            entities=[entity],
+            schema=[
+                Field(name="doc_id", dtype=Int64),
+                Field(
+                    name="vec",
+                    dtype=Array(Float32),
+                    vector_index=True,
+                    vector_search_metric="COSINE",
+                ),
+                Field(name="text", dtype=String),
+            ],
+            source=source,
+            ttl=timedelta(hours=1),
+        )
+        store.apply([source, entity, fv])
+
+        online_store = store._provider._online_store
+        fv_obj = store.get_feature_view("docs")
+        # Simulate a search hit that is missing the composite primary key.
+        fake_hit = {
+            "entity": {
+                "event_ts": int(_utc_now().timestamp() * 1e6),
+                "created_ts": int(_utc_now().timestamp() * 1e6),
+                "text": "hello",
+            },
+            "distance": 0.9,
+        }
+
+        mock_results = [[fake_hit]]
+        with patch.object(online_store.client, "search", return_value=mock_results):
+            with patch.object(
+                online_store.client, "load_collection", return_value=None
+            ):
+                # Before the fix this raised TypeError: fromhex argument must be str, not None
+                result = online_store.retrieve_online_documents_v2(
+                    config=store.config,
+                    table=fv_obj,
+                    requested_features=["text"],
+                    embedding=[0.1] * 10,
+                    top_k=1,
+                )
+        assert len(result) == 1
+        _ts, entity_key_proto, _features = result[0]
+        assert entity_key_proto is None, (
+            "entity_key_proto should be None when the composite key is absent from the hit"
+        )