diff --git a/README.md b/README.md
index ad727a4..b3e0afb 100644
--- a/README.md
+++ b/README.md
@@ -32,7 +32,7 @@
   <a href="https://x.com/ZvecAI">🐦 <strong>X (Twitter)</strong> </a>
 </p>
 
-**Zvec** is an open-source, in-process vector database — lightweight, lightning-fast, and designed to embed directly into applications. Built on **Proxima** (Alibaba's battle-tested vector search engine), it delivers production-grade, low-latency, scalable similarity search with minimal setup.
+**Zvec** is an open-source, in-process vector database — lightweight, lightning-fast, and designed to embed directly into applications. Battle-tested within Alibaba Group, it delivers production-grade, low-latency and scalable similarity search with minimal setup.
 
 > [!Important]
 > 🚀 **v0.3.1 (Apr 17, 2026)**
diff --git a/src/db/collection.cc b/src/db/collection.cc
index c554149..e75492b 100644
--- a/src/db/collection.cc
+++ b/src/db/collection.cc
@@ -624,10 +624,11 @@ Status CollectionImpl::execute_tasks(
 
 Status CollectionImpl::DropIndex(const std::string &column_name) {
   CHECK_COLLECTION_READONLY_RETURN_STATUS;
-  CHECK_DESTROY_RETURN_STATUS(destroyed_, false);
 
   std::lock_guard lock(schema_handle_mtx_);
 
+  CHECK_DESTROY_RETURN_STATUS(destroyed_, false);
+
   auto new_schema = std::make_shared<CollectionSchema>(*schema_);
   auto s = new_schema->drop_index(column_name);
   CHECK_RETURN_STATUS(s);
@@ -1548,8 +1549,6 @@ Status CollectionImpl::DeleteByFilter(const std::string &filter) {
 
   CHECK_DESTROY_RETURN_STATUS(destroyed_, false);
 
-  auto segments = get_all_segments();
-
   VectorQuery query;
   query.filter_ = filter;
   query.topk_ = INT32_MAX;
diff --git a/src/db/common/concurrent_roaring_bitmap.h b/src/db/common/concurrent_roaring_bitmap.h
index 8d5f106..d1c6bd4 100644
--- a/src/db/common/concurrent_roaring_bitmap.h
+++ b/src/db/common/concurrent_roaring_bitmap.h
@@ -79,7 +79,8 @@ class ConcurrentRoaringBitmap32 {
     std::shared_lock<std::shared_mutex> lock(mutex_);
     uint64_t max_rank{0}, min_rank{0};
     max_rank = roaring_bitmap_rank(bitmap_, max_doc_id);
-    min_rank = roaring_bitmap_rank(bitmap_, min_doc_id - 1);
+    min_rank =
+        min_doc_id == 0 ? 0 : roaring_bitmap_rank(bitmap_, min_doc_id - 1);
     return max_rank - min_rank;
   }
 
diff --git a/src/db/common/error_code.cc b/src/db/common/error_code.cc
index d24c9cd..df7211a 100644
--- a/src/db/common/error_code.cc
+++ b/src/db/common/error_code.cc
@@ -123,8 +123,10 @@ PROXIMA_ZVEC_ERROR_CODE_DEFINE(InvalidCollectionName, 2042,
 PROXIMA_ZVEC_ERROR_CODE_DEFINE(InvalidPartitionName, 2043,
                                "Invalid partition name");
 PROXIMA_ZVEC_ERROR_CODE_DEFINE(InvalidFieldName, 2044, "Invalid field name");
-PROXIMA_ZVEC_ERROR_CODE_DEFINE(InvalidChannelCount, 2045, "Invalid field name");
-PROXIMA_ZVEC_ERROR_CODE_DEFINE(InvalidReplicaCount, 2046, "Invalid field name");
+PROXIMA_ZVEC_ERROR_CODE_DEFINE(InvalidChannelCount, 2045,
+                               "Invalid channel count");
+PROXIMA_ZVEC_ERROR_CODE_DEFINE(InvalidReplicaCount, 2046,
+                               "Invalid replica count");
 PROXIMA_ZVEC_ERROR_CODE_DEFINE(InvalidJson, 2047, "Invalid json");
 // used by master
 PROXIMA_ZVEC_ERROR_CODE_DEFINE(InvalidClusterConfig, 2048,
diff --git a/src/db/common/error_code.h b/src/db/common/error_code.h
index 625cd66..71b7308 100644
--- a/src/db/common/error_code.h
+++ b/src/db/common/error_code.h
@@ -144,8 +144,6 @@ PROXIMA_ZVEC_ERROR_CODE_DECLARE(UnreadyQueue);
 PROXIMA_ZVEC_ERROR_CODE_DECLARE(ScheduleError);
 PROXIMA_ZVEC_ERROR_CODE_DECLARE(TaskIsRunning);
 
-PROXIMA_ZVEC_ERROR_CODE_DECLARE(DirectoryAlreadyExists);
-PROXIMA_ZVEC_ERROR_CODE_DECLARE(DirectoryNotExists);
 
 // 2000~2999 [Client Check]
 PROXIMA_ZVEC_ERROR_CODE_DECLARE(EmptyCollectionName);
diff --git a/src/db/common/file_helper.h b/src/db/common/file_helper.h
index 7be6090..95d5b2a 100644
--- a/src/db/common/file_helper.h
+++ b/src/db/common/file_helper.h
@@ -41,7 +41,7 @@ enum class FileID : uint32_t {
 /*
  * File name coresponding to file id
  */
-static const char *GetFileName(FileID t) {
+inline const char *GetFileName(FileID t) {
   switch (t) {
     case FileID::ID_FILE:
       return "idmap";
diff --git a/src/db/common/rocbsdb_context.cc b/src/db/common/rocksdb_context.cc
similarity index 100%
rename from src/db/common/rocbsdb_context.cc
rename to src/db/common/rocksdb_context.cc
index 790456a..42867cc 100644
--- a/src/db/common/rocbsdb_context.cc
+++ b/src/db/common/rocksdb_context.cc
@@ -13,12 +13,12 @@
 // limitations under the License.
 
 
+#include "rocksdb_context.h"
 #include <rocksdb/filter_policy.h>
 #include <rocksdb/statistics.h>
 #include <rocksdb/table.h>
 #include <rocksdb/utilities/checkpoint.h>
 #include <zvec/ailego/logger/logger.h>
-#include "rocksdb_context.h"
 
 
 namespace zvec {
diff --git a/src/db/common/utils.h b/src/db/common/utils.h
index 43369f1..c238b92 100644
--- a/src/db/common/utils.h
+++ b/src/db/common/utils.h
@@ -11,6 +11,8 @@
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
+#pragma once
+
 #include <string>
 
 namespace zvec {
diff --git a/src/include/zvec/db/doc.h b/src/include/zvec/db/doc.h
index d8d649e..c78028c 100644
--- a/src/include/zvec/db/doc.h
+++ b/src/include/zvec/db/doc.h
@@ -323,8 +323,8 @@ class Doc {
  private:
   std::string pk_;
   float score_{0.0f};
-  uint64_t doc_id_;
-  Operator op_;
+  uint64_t doc_id_{0};
+  Operator op_{Operator::INSERT};
 
   template <typename T>
   static constexpr bool is_valid_type_v =
@@ -341,17 +341,17 @@ class Doc {
       std::is_same_v<T, std::vector<int8_t>> ||       // 10
       std::is_same_v<T, std::vector<int16_t>> ||      // 11
       std::is_same_v<T, std::vector<int32_t>> ||      // 12
-      std::is_same_v<T, std::vector<uint32_t>> ||     // 13
-      std::is_same_v<T, std::vector<int64_t>> ||      // 14
+      std::is_same_v<T, std::vector<int64_t>> ||      // 13
+      std::is_same_v<T, std::vector<uint32_t>> ||     // 14
       std::is_same_v<T, std::vector<uint64_t>> ||     // 15
       std::is_same_v<T, std::vector<float16_t>> ||    // 16
       std::is_same_v<T, std::vector<float>> ||        // 17
       std::is_same_v<T, std::vector<double>> ||       // 18
       std::is_same_v<T, std::vector<std::string>> ||  // 19
       std::is_same_v<
-          T, std::pair<std::vector<uint32_t>, std::vector<float16_t>>> ||  // 20
+          T, std::pair<std::vector<uint32_t>, std::vector<float>>> ||  // 20
       std::is_same_v<
-          T, std::pair<std::vector<uint32_t>, std::vector<float>>>;  // 21
+          T, std::pair<std::vector<uint32_t>, std::vector<float16_t>>>;  // 21
 
   std::unordered_map<std::string, Value> fields_;
 };
diff --git a/src/include/zvec/db/options.h b/src/include/zvec/db/options.h
index 1f2a9cb..8c3e8c5 100644
--- a/src/include/zvec/db/options.h
+++ b/src/include/zvec/db/options.h
@@ -17,11 +17,11 @@
 
 namespace zvec {
 
-const uint32_t DEFAULT_MAX_BUFFER_SIZE = 64 * 1024 * 1024;  // 128M
+const uint32_t DEFAULT_MAX_BUFFER_SIZE = 64 * 1024 * 1024;  // 64M
 
 struct CollectionOptions {
   bool read_only_{false};
-  bool enable_mmap_{true};  // ignnored when load collection
+  bool enable_mmap_{true};  // ignored when load collection
   uint32_t max_buffer_size_{
       DEFAULT_MAX_BUFFER_SIZE};  // ignored when read_only=true