diff --git a/src/ailego/buffer/parquet_hash_table.cc b/src/ailego/buffer/parquet_hash_table.cc
index ab519843e..be8833976 100644
--- a/src/ailego/buffer/parquet_hash_table.cc
+++ b/src/ailego/buffer/parquet_hash_table.cc
@@ -141,11 +141,18 @@ ParquetBufferContextHandle ParquetBufferPool::acquire_buffer(
       return ParquetBufferContextHandle();
     }
     std::unique_lock<std::shared_mutex> lock(table_mutex_);
-    if (acquire(buffer_id, table_[buffer_id]).ok()) {
-      MemoryLimitPool::get_instance().acquire_parquet(table_[buffer_id].size);
-      arrow = set_block_acquired(buffer_id);
+    auto [iter, inserted] = table_.try_emplace(buffer_id);
+    ParquetBufferContext &context = iter->second;
+    if (!inserted) {
+      arrow = set_block_acquired(context);
+      return ParquetBufferContextHandle(buffer_id, arrow);
+    }
+    if (acquire(buffer_id, context).ok()) {
+      MemoryLimitPool::get_instance().acquire_parquet(context.size);
+      arrow = set_block_acquired(context);
       return ParquetBufferContextHandle(buffer_id, arrow);
     } else {
+      table_.erase(iter);
       LOG_ERROR("Failed to acquire parquet buffer: %s",
                 buffer_id.to_string().c_str());
       return ParquetBufferContextHandle();
@@ -154,25 +161,14 @@ ParquetBufferContextHandle ParquetBufferPool::acquire_buffer(
 }
 
 std::shared_ptr<arrow::ChunkedArray> ParquetBufferPool::set_block_acquired(
-    ParquetBufferID buffer_id) {
-  ParquetBufferContext &context = table_[buffer_id];
-  while (true) {
-    int current_count = context.ref_count.load(std::memory_order_relaxed);
-    if (current_count >= 0) {
-      if (context.ref_count.compare_exchange_weak(
-              current_count, current_count + 1, std::memory_order_acq_rel,
-              std::memory_order_acquire)) {
-        return context.arrow;
-      }
-    } else {
-      if (context.ref_count.compare_exchange_weak(current_count, 1,
-                                                  std::memory_order_acq_rel,
-                                                  std::memory_order_acquire)) {
-        context.load_count.fetch_add(1, std::memory_order_relaxed);
-        return context.arrow;
-      }
-    }
+    ParquetBufferContext &context) {
+  int current_count = context.ref_count.load(std::memory_order_relaxed);
+  if (current_count <= 0) {
+    context.load_count.fetch_add(1, std::memory_order_relaxed);
+    current_count = 0;
   }
+  context.ref_count.store(current_count + 1, std::memory_order_release);
+  return context.arrow;
 }
 
 std::shared_ptr<arrow::ChunkedArray> ParquetBufferPool::acquire(
@@ -181,7 +177,7 @@ std::shared_ptr<arrow::ChunkedArray> ParquetBufferPool::acquire(
   if (iter == table_.end()) {
     return nullptr;
   }
-  ParquetBufferContext &context = table_[buffer_id];
+  ParquetBufferContext &context = iter->second;
   while (true) {
     int current_count = context.ref_count.load(std::memory_order_acquire);
     if (current_count < 0) {
@@ -196,7 +192,6 @@ std::shared_ptr<arrow::ChunkedArray> ParquetBufferPool::acquire(
       return context.arrow;
     }
   }
-  return nullptr;
 }
 
 std::shared_ptr<arrow::ChunkedArray> ParquetBufferPool::acquire_locked(
@@ -211,7 +206,7 @@ void ParquetBufferPool::release(ParquetBufferID buffer_id) {
   if (iter == table_.end()) {
     return;
   }
-  ParquetBufferContext &context = table_[buffer_id];
+  ParquetBufferContext &context = iter->second;
   if (context.ref_count.fetch_sub(1, std::memory_order_release) == 1) {
     std::atomic_thread_fence(std::memory_order_acquire);
     BlockEvictionQueue::BlockType block;
@@ -227,13 +222,14 @@ void ParquetBufferPool::evict(ParquetBufferID buffer_id) {
   if (iter == table_.end()) {
     return;
   }
-  ParquetBufferContext &context = table_[buffer_id];
+  ParquetBufferContext &context = iter->second;
   int expected = 0;
   if (context.ref_count.compare_exchange_strong(
           expected, std::numeric_limits<int>::min())) {
     MemoryLimitPool::get_instance().release_parquet(context.size);
     context.arrow = nullptr;
     context.arrow_refs.clear();
+    table_.erase(iter);
   }
 }
 
diff --git a/src/include/zvec/ailego/buffer/parquet_hash_table.h b/src/include/zvec/ailego/buffer/parquet_hash_table.h
index 4db1a8f3d..bc99b2c3e 100644
--- a/src/include/zvec/ailego/buffer/parquet_hash_table.h
+++ b/src/include/zvec/ailego/buffer/parquet_hash_table.h
@@ -105,6 +105,8 @@ class ParquetBufferContextHandle {
 };
 
 class ParquetBufferPool {
+  friend class ParquetBufferContextHandle;
+
  public:
   typedef std::shared_ptr<ParquetBufferPool> Pointer;
 
@@ -123,21 +125,8 @@ class ParquetBufferPool {
   using Table = std::unordered_map<ParquetBufferID, ParquetBufferContext,
                                    IDHash, IDEqual>;
 
-  arrow::Status acquire(ParquetBufferID buffer_id,
-                        ParquetBufferContext &context);
-
   ParquetBufferContextHandle acquire_buffer(ParquetBufferID buffer_id);
 
-  std::shared_ptr<arrow::ChunkedArray> set_block_acquired(
-      ParquetBufferID buffer_id);
-
-  std::shared_ptr<arrow::ChunkedArray> acquire(ParquetBufferID buffer_id);
-
-  std::shared_ptr<arrow::ChunkedArray> acquire_locked(
-      ParquetBufferID buffer_id);
-
-  void release(ParquetBufferID buffer_id);
-
   void evict(ParquetBufferID buffer_id);
 
   bool is_dead_node(BlockEvictionQueue::BlockType &block);
@@ -155,6 +144,19 @@ class ParquetBufferPool {
  private:
   ParquetBufferPool() = default;
 
+  std::shared_ptr<arrow::ChunkedArray> acquire_locked(
+      ParquetBufferID buffer_id);
+
+  void release(ParquetBufferID buffer_id);
+
+  arrow::Status acquire(ParquetBufferID buffer_id,
+                        ParquetBufferContext &context);
+
+  std::shared_ptr<arrow::ChunkedArray> acquire(ParquetBufferID buffer_id);
+
+  std::shared_ptr<arrow::ChunkedArray> set_block_acquired(
+      ParquetBufferContext &context);
+
  private:
   Table table_;
   std::shared_mutex table_mutex_;