update to_string

Author: zhangstar333

be/src/vec/common/string_view.h

@@ -126,16 +126,15 @@ class StringView {
     std::string dump_hex() const {
         static const char* kHex = "0123456789ABCDEF";
         std::string out;
-        out.reserve(size_ * 2 + 3);
-        out.push_back('X');
-        out.push_back('\'');
+        out.reserve(size_ * 2 + 2);
+        out.push_back('0');
+        out.push_back('x');
         const char* ptr = data();
         for (uint32_t i = 0; i < size_; ++i) {
             auto c = static_cast<unsigned char>(ptr[i]);
             out.push_back(kHex[c >> 4]);
             out.push_back(kHex[c & 0x0F]);
         }
-        out.push_back('\'');
         return out;
     }
 

be/src/vec/data_types/serde/data_type_varbinary_serde.cpp

@@ -41,7 +41,7 @@ Status DataTypeVarbinarySerDe::write_column_to_mysql_binary(const IColumn& colum
                                                             int64_t row_idx, bool col_const,
                                                             const FormatOptions& options) const {
     auto col_index = index_check_const(row_idx, col_const);
-    auto data = assert_cast<const ColumnVarbinary&>(column).get_data()[col_index];
+    const auto& data = assert_cast<const ColumnVarbinary&>(column).get_data()[col_index];
 
     if (0 != result.push_string(data.data(), data.size())) {
         return Status::InternalError("pack mysql buffer failed.");
@@ -62,7 +62,7 @@ Status DataTypeVarbinarySerDe::write_column_to_arrow(const IColumn& column, cons
                                                  builder.type()->name()));
                 continue;
             }
-            auto string_view = varbinary_column_data[i];
+            const auto& string_view = varbinary_column_data[i];
             RETURN_IF_ERROR(checkArrowStatus(builder.Append(string_view.data(), string_view.size()),
                                              column.get_name(), builder.type()->name()));
         }
@@ -117,8 +117,13 @@ Status DataTypeVarbinarySerDe::deserialize_one_cell_from_json(IColumn& column, S
 
 void DataTypeVarbinarySerDe::to_string(const IColumn& column, size_t row_num,
                                        BufferWritable& bw) const {
-    const auto value = assert_cast<const ColumnVarbinary&>(column).get_data_at(row_num);
-    bw.write(value.data, value.size);
+    const auto& value = assert_cast<const ColumnVarbinary&>(column).get_data()[row_num];
+    if (_nesting_level >= 2) { // in complex type, need to dump as hex string by hand
+        const auto& hex_str = value.dump_hex();
+        bw.write(hex_str.data(), hex_str.size());
+    } else { // mysql protocol will be handle as hex binary data directly
+        bw.write(value.data(), value.size());
+    }
 }
 
 } // namespace doris::vectorized