refactor: remove WriteBuffer GetBatchCount

Author: zjw1111

src/paimon/core/mergetree/write_buffer.h

@@ -61,17 +61,17 @@ class WriteBuffer {
     /// Flush all buffered batches into KeyValueInMemoryRecordReaders and clear the buffer.
     /// @param[in,out] last_sequence_number current sequence number, updated after flush
     /// @return list of KeyValueRecordReaders built from buffered data
-    Result<std::vector<std::unique_ptr<KeyValueRecordReader>>> Flush(
-        int64_t& last_sequence_number);
+    Result<std::vector<std::unique_ptr<KeyValueRecordReader>>> Flush(int64_t& last_sequence_number);
 
     /// Return current memory usage in bytes.
-    int64_t GetMemoryUsage() const { return current_memory_in_bytes_; }
+    int64_t GetMemoryUsage() const {
+        return current_memory_in_bytes_;
+    }
 
     /// Return whether the buffer is empty.
-    bool IsEmpty() const { return batch_vec_.empty(); }
-
-    /// Return the number of batches in the buffer.
-    size_t GetBatchCount() const { return batch_vec_.size(); }
+    bool IsEmpty() const {
+        return batch_vec_.empty();
+    }
 
     /// Clear the buffer without building readers (for error paths or Close).
     void Clear();

src/paimon/core/mergetree/write_buffer_test.cpp

@@ -97,15 +97,13 @@ TEST_F(WriteBufferTest, TestFlushResetsStateAndAdvancesSequenceNumber) {
     ASSERT_OK(write_buffer.Write(CreateBatch(array1, /*row_kinds=*/{})));
     ASSERT_OK(write_buffer.Write(CreateBatch(array2, /*row_kinds=*/{})));
     ASSERT_FALSE(write_buffer.IsEmpty());
-    ASSERT_EQ(write_buffer.GetBatchCount(), 2);
     ASSERT_GT(write_buffer.GetMemoryUsage(), 0);
 
     int64_t last_sequence_number = 10;
     ASSERT_OK_AND_ASSIGN(auto readers, write_buffer.Flush(last_sequence_number));
 
     ASSERT_EQ(readers.size(), 2);
     ASSERT_TRUE(write_buffer.IsEmpty());
-    ASSERT_EQ(write_buffer.GetBatchCount(), 0);
     ASSERT_EQ(write_buffer.GetMemoryUsage(), 0);
     ASSERT_EQ(last_sequence_number, 13);
 
@@ -168,10 +166,9 @@ TEST_F(WriteBufferTest, TestFlushPreservesRowKinds) {
     }
 
     ASSERT_EQ(actual_row_kind_values,
-              (std::vector<int8_t>{RowKind::Insert()->ToByteValue(),
-                                   RowKind::UpdateBefore()->ToByteValue(),
-                                   RowKind::UpdateAfter()->ToByteValue(),
-                                   RowKind::Delete()->ToByteValue()}));
+              (std::vector<int8_t>{
+                  RowKind::Insert()->ToByteValue(), RowKind::UpdateBefore()->ToByteValue(),
+                  RowKind::UpdateAfter()->ToByteValue(), RowKind::Delete()->ToByteValue()}));
     ASSERT_EQ(actual_sequence_numbers, (std::vector<int64_t>{0, 1, 2, 3}));
 }
 
@@ -223,8 +220,8 @@ TEST_F(WriteBufferTest, TestEstimateMemoryUse) {
             arrow::field("f0", arrow::list(arrow::int32())),
             arrow::field("f1", arrow::map(arrow::utf8(), arrow::int64())),
             arrow::field("f2", arrow::struct_({arrow::field("sub1", arrow::int64()),
-                                                arrow::field("sub2", arrow::float64()),
-                                                arrow::field("sub3", arrow::boolean())})),
+                                               arrow::field("sub2", arrow::float64()),
+                                               arrow::field("sub3", arrow::boolean())})),
         };
         auto array = std::dynamic_pointer_cast<arrow::StructArray>(
             arrow::ipc::internal::json::ArrayFromJSON(arrow::struct_({fields}), R"([
@@ -242,4 +239,4 @@ TEST_F(WriteBufferTest, TestEstimateMemoryUse) {
     }
 }
 
-}  // namespace paimon::test
+}  // namespace paimon::test