distsql

type PartialResult interface {
	// Next returns the next row of the sub result.
	// If no more row to return, data would be nil.
	Next() (handle int64, data []types.Datum, err error)
	// Close closes the partial result.
	Close() error
}

type SelectResult interface {
	// Next gets the next partial result.
	Next() (PartialResult, error)
	// SetFields sets the expected result type.
	SetFields(fields []*types.FieldType)
	// Close closes the iterator.
	Close() error
	// Fetch fetches partial results from client.
	// The caller should call SetFields() before call Fetch().
	Fetch()
	// IgnoreData sets ignore data attr to true.
	// For index double scan, we do not need row data when scanning index.
	IgnoreData()
}