# Efficient way to reindex a big index using parent/child to ES 2.0
**URL:** https://discuss.elastic.co/t/efficient-way-to-reindex-a-big-index-using-parent-child-to-es-2-0/34602
**Category:** Elasticsearch
**Created:** [November 14, 2015, 10:51pm UTC](https://discuss.elastic.co/t/efficient-way-to-reindex-a-big-index-using-parent-child-to-es-2-0/34602 "2015-11-14T22:51:42Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@przemekpokrywka](https://discuss.elastic.co/u/przemekpokrywka)
#### Post date: [November 14, 2015, 10:51pm UTC](https://discuss.elastic.co/t/efficient-way-to-reindex-a-big-index-using-parent-child-to-es-2-0/34602/1 "2015-11-14T22:51:42Z")
Hello,
I've read about memory and performance improvements of parent/child handling in ES 2.0 and I want to benefit from it.
The docs advise to reindex my index that use \_parent field ([https://www.elastic.co/guide/en/elasticsearch/reference/2.0/breaking\_20\_parent\_child\_changes.html](https://www.elastic.co/guide/en/elasticsearch/reference/2.0/breaking_20_parent_child_changes.html)).
I'm looking for advice what would be the easiest/fastest way to do it?
The docs say: "The refactored and improved implementation is only active for indices created on or after version 2.0."
Is there a better way (in terms of human effort and processing time), than just to create a new index and indexing all of my data once again?
For example if I made a snaphot of my ES 1.7 index and tried to restore it, would it automatically become performant, ES 2.0 index?
Thanks,
Przemek
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### Author:  [@warkolm](https://discuss.elastic.co/u/warkolm)
#### Post date: [November 16, 2015, 3:30am UTC](https://discuss.elastic.co/t/efficient-way-to-reindex-a-big-index-using-parent-child-to-es-2-0/34602/2 "2015-11-16T03:30:43Z")
Snapshot and restore won't work, it needs to be a reindex.
The official clients all have functions that should help!
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### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [July 5, 2017, 11:38pm UTC](https://discuss.elastic.co/t/efficient-way-to-reindex-a-big-index-using-parent-child-to-es-2-0/34602/3 "2017-07-05T23:38:20Z")