Method optimize

iterator.go:455–483

-------------------------------------------- The optimize method tries to optimize an iterator. For example, when there's only a single segment, then the heap can be avoided by using a simpler, faster iteratorSingle implementation.

()

// when there's only a single segment, then the heap can be avoided by
// using a simpler, faster iteratorSingle implementation.
func (iter *iterator) optimize() (Iterator, error) {
	if len(iter.cursors) != 1 {
		return iter, nil
	}

	cur := iter.cursors[0]

	if cur.ssIndex == -1 && cur.sc == nil {
		// Optimization to return lowerLevelIter directly.
		return iter.lowerLevelIter, nil
	}

	seg, ok := iter.ss.a[cur.ssIndex].(*segment)
	if !ok || seg == nil {
		return iter, nil
	}

	return &iteratorSingle{
		s:       seg,
		sc:      cur.sc,
		op:      cur.op,
		k:       cur.k,
		v:       cur.v,
		closer:  iter.closer,
		options: iter.ss.options,

		iteratorOptions: iter.iteratorOptions,
	}, nil
}

// --------------------------------------------