# Reviewing ES for parent/child aggregation

**URL:** <https://discuss.elastic.co/t/reviewing-es-for-parent-child-aggregation/7074>\
**Category:** Elasticsearch\
**Created:** [March 20, 2012, 5:40pm UTC](https://discuss.elastic.co/t/reviewing-es-for-parent-child-aggregation/7074 "2012-03-20T17:40:31Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![ripplekhera](https://avatars.discourse-cdn.com/v4/letter/r/aeb1de/32.png) [@ripplekhera](https://discuss.elastic.co/u/ripplekhera)\
**Post date:** [March 20, 2012, 5:40pm UTC](https://discuss.elastic.co/t/reviewing-es-for-parent-child-aggregation/7074/1 "2012-03-20T17:40:31Z")

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I am reviewing ES to replace our current setup of homegrown indexing built  
with Riak + Riak Search. Our current setup is not exactly epic fail, but  
definitely not giving us what we need. And of course, I am trying to build  
this while a current live application already exists, so it had to be did  
yesterday.

My major requirements are:

1. Modeling a one to many relationship. Think of it as Books + Paragraph.  
Books have attributes as Author, PublishTime (year+month), Title, Amazon  
link. Paragraphs belong to a book and have words, numerical score, start  
and end position within the book.

Book (Author, Date, Title, Url, Content)  
|  
|--\> Paragraph (Words, Score, StartPosition, EndPosition)

This is not the true model but a very close analogy.

1. Performing computations (such average score for words) based on date,  
with the result grouped by book. So essentially, its aggregating the score  
from the paragraphs and grouping by book. Also finding, "other" words that  
are significant based on current date and word query.

2. Scale: Currently there are millions of 'book' objects, which could grow  
to billions or more. We could have to report on 10 million book objects at  
one time, which could involve aggregating 100 million paragraph objects  
using some computation. I am hoping to use statistical facets and/or  
scripting to move this to ES instead of transporting it to the app level  
and doing aggregations using Java lists.

My main questions:

1. Do you think ES is a good fit for search+compute? Will the statistical  
facet work for my requirements?

2. Should I model the data as Parent/Child or Nested Documents? I need to  
search by Parent, but aggregate by Child. Based on my reading of the  
reference material and this forum, that is not possible using the  
Parent/Child schema since the only thing available is the has\_child filter  
which does not allow you to do computations on the children, just filter by  
them.

3. Will ES be able to handle this scale?

4. Are the computations I need to perform possible using the stastical  
facets and/or scripting?

Please do get back to me quickly, so I know I am making the right design  
decisions from the get go.

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**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [July 6, 2017, 3:35am UTC](https://discuss.elastic.co/t/reviewing-es-for-parent-child-aggregation/7074/2 "2017-07-06T03:35:26Z")

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Closed on July 6, 2017, 3:35am UTC