# Is there a way to copy a subset of data from one elasticsearch index to another?
**URL:** https://discuss.elastic.co/t/is-there-a-way-to-copy-a-subset-of-data-from-one-elasticsearch-index-to-another/23590
**Category:** Elasticsearch
**Created:** [May 8, 2015, 9:28pm UTC](https://discuss.elastic.co/t/is-there-a-way-to-copy-a-subset-of-data-from-one-elasticsearch-index-to-another/23590 "2015-05-08T21:28:32Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@Gerald\_DeConto](https://discuss.elastic.co/u/Gerald_DeConto)
#### Post date: [May 8, 2015, 9:28pm UTC](https://discuss.elastic.co/t/is-there-a-way-to-copy-a-subset-of-data-from-one-elasticsearch-index-to-another/23590/1 "2015-05-08T21:28:32Z")
hi all
I am looking for a way to copy a subset of data (this could mean only some
documents, or only some fields from the documents) from one elasticsearch
index to another in the same cluster
Scenario: I have a potentially very large index (with billions of
documents). I need the fine details for a period of time, but after that
period it would be useful to only have a subset of the data (filtered by
some criteria or only returning certain fields) so that our indexes dont
become needlessly bloated with less useful data.
In this situation, I don't think that we can use date-based indexes (ie
mydata-2015-05030) as the data doesnt really have a specific date to use.
I do see that there's a couple of java/node based tools, and a plugin named
knapsack ([https://github.com/jprante/elasticsearch-knapsack](https://github.com/jprante/elasticsearch-knapsack)). Hard to tell
from the docs if they can do what I am trying to do.
Has anyone had to deal with situation, copying a subset of data from one
index/cluster to a new index/cluster? If so, what are you using??
Thanks in advance for any help
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### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [July 6, 2017, 12:14am UTC](https://discuss.elastic.co/t/is-there-a-way-to-copy-a-subset-of-data-from-one-elasticsearch-index-to-another/23590/2 "2017-07-06T00:14:58Z")