Method TryCompact

be/src/exec/scratch-tuple-batch.h:156–176

Try to compact 'num_uncommitted_tuples' uncommitted tuples that were added to the end of 'dst_batch' by copying them to memory allocated from dst_batch->tuple_data_pool(). Returns true on success or false if the memory could not be allocated.

  /// dst_batch->tuple_data_pool(). Returns true on success or false if the memory
  /// could not be allocated.
  bool TryCompact(RowBatch* dst_batch, int num_uncommitted_tuples) {
    DCHECK_LE(dst_batch->num_rows() + num_uncommitted_tuples, dst_batch->capacity());
    // Copy rows that reference 'tuple_mem' into a new small buffer. This code handles
    // the case where num_uncommitted_tuples == 0, since TryAllocate() returns a non-null
    // pointer.
    int64_t dst_bytes = num_uncommitted_tuples * static_cast<int64_t>(tuple_byte_size);
    uint8_t* dst_buffer = dst_batch->tuple_data_pool()->TryAllocate(dst_bytes);
    if (dst_buffer == nullptr) return false;
    const int end_row = dst_batch->num_rows() + num_uncommitted_tuples;
    for (int i = dst_batch->num_rows(); i < end_row; ++i) {
      TupleRow* row = dst_batch->GetRow(i);
      Tuple* uncompacted_tuple = row->GetTuple(0);
      DCHECK_GE(reinterpret_cast<uint8_t*>(uncompacted_tuple), tuple_mem);
      DCHECK_LT(reinterpret_cast<uint8_t*>(uncompacted_tuple),
          tuple_mem + tuple_byte_size * capacity);
      row->SetTuple(0, reinterpret_cast<Tuple*>(dst_buffer));
      memcpy(dst_buffer, uncompacted_tuple, tuple_byte_size);
      dst_buffer += tuple_byte_size;
    }
    return true;
  }

  /// Creates micro batches that needs to be scanned.
  /// Bits set in 'selected_rows' are the rows that needs to be scanned. Consecutive