# Proper buckets\_path value for a Filters Aggregation?
**URL:** https://discuss.elastic.co/t/proper-buckets-path-value-for-a-filters-aggregation/57754
**Category:** Elasticsearch
**Created:** [August 11, 2016, 3:53am UTC](https://discuss.elastic.co/t/proper-buckets-path-value-for-a-filters-aggregation/57754 "2016-08-11T03:53:48Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@nfantone](https://discuss.elastic.co/u/nfantone)
#### Post date: [August 11, 2016, 3:53am UTC](https://discuss.elastic.co/t/proper-buckets-path-value-for-a-filters-aggregation/57754/1 "2016-08-11T03:53:48Z")
Hi everyone!
I'm struggling with generating a query that fits the following scenario:
- A single index with two types: `purchase` and `search`.
- Given a multi-bucket metric (say, `histogram`), calculate for each bucket the ratio or quotient of the count of documents on both types.
So far, I've managed to put together something like this:
```
{
"aggs": {
"conversion_rate_m": {
"filters": {
"filters": {
"abandon": {
"bool": {
"must": {
"type": {
"value": "search"
}
}
}
},
"conversion": {
"bool": {
"must": {
"type": {
"value": "purchase"
}
}
}
}
}
},
"aggs": {
"conversion_abandon": {
"cardinality": {
"field": "_uid"
}
}
}
},
"conversion_rate_m_metadata": {
"bucket_script": {
"buckets_path": {
"convert": "conversion_rate_m> ?", // <-- No idea here
"abandon": "conversion_rate_m> ?" // <-- ...nor here
},
"script": "convert / abandon"
}
}
}
}
```
However, I failed to guess which are the actual values for `buckets_path` that would please Elasticsearch. Tried many possible combinations, up to a point where I was just guessing things up. To make matters worse, documentation is incredibly vague and obscure on the topic.
I also tried omitting the `cardinality` agg altogether and just make use of the `doc_count` value produced by each of the `filters`, but no avail. Stumbled upon the same problem: generating a proper `bucket_path` for the script to work.
So, which value should I use? Or maybe suggest a better way of going about this?
Thank you very much.
---
### Author:  [@colings86](https://discuss.elastic.co/u/colings86)
#### Post date: [August 11, 2016, 8:14am UTC](https://discuss.elastic.co/t/proper-buckets-path-value-for-a-filters-aggregation/57754/2 "2016-08-11T08:14:15Z")
The issue here is that currently you cannot define a `buckets_path` that traverses through a multi bucket aggregation. Luckily for your use case you can instead use the single bucket aggregation `filter` rather than the multi bucket aggregation `filters`. Try the following (untested):
```auto
{
"aggs": {
"abandon": {
"filter": {
"bool": {
"must": {
"type": {
"value": "search"
}
}
}
},
"aggs": {
"distinct": {
"cardinality": {
"field": "_uid"
}
}
}
},
"conversion": {
"filter": {
"bool": {
"must": {
"type": {
"value": "purchase"
}
}
}
},
"aggs": {
"distinct": {
"cardinality": {
"field": "_uid"
}
}
}
}
},
"conversion_rate_m_metadata": {
"bucket_script": {
"buckets_path": {
"convert": "conversion>distinct",
"abandon": "abandon>distinct"
},
"script": "convert / abandon"
}
}
}
```
Hope that helps
---
### Author:  [@nfantone](https://discuss.elastic.co/u/nfantone)
#### Post date: [August 11, 2016, 3:59pm UTC](https://discuss.elastic.co/t/proper-buckets-path-value-for-a-filters-aggregation/57754/3 "2016-08-11T15:59:16Z")
Hey, thanks for your reply!
Yes, that was, in fact, my first approach. But lead me to a different issue. This is what I had, previously (renaming aggs after your suggestion):
```
{ "aggs": {
"abandon": {
"filter": {
"bool": {
"must": {
"type": {
"value": "search"
}
}
}
},
"aggs": {
"distinct": {
"cardinality": {
"field": "_uid"
}
}
}
},
"conversion": {
"filter": {
"bool": {
"must": {
"type": {
"value": "purchase"
}
}
}
},
"aggs": {
"distinct": {
"cardinality": {
"field": "_uid"
}
}
}
},
"conversion_abandon_rate": {
"bucket_script": {
"buckets_path": {
"convert": "conversion>distinct",
"abandon": "abandon>distinct"
},
"script": "convert / Math.max(abandon, 1.0)"
}
}
}
```
Running that produces a `503` response with:
```
{
"response": {
"error ": {
"root_cause ": [],
"type ": "reduce_search_phase_exception",
"reason": "[reduce]",
"phase": "fetch",
"grouped": true,
"caused_by": {
"type": "class_cast_exception",
"reason ": "org.elasticsearch.search.aggregations.bucket.filter.InternalFilter cannot be cast to org.elasticsearch.search.aggregations.InternalMultiBucketAggregation"
}
},
"status": 503
}
}
```
Which puzzled me because I'm not using _any_ multi bucket aggregation in my query and can't see why the engine is trying to cast a filter to one.
Any thoughts?
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [July 5, 2017, 10:28pm UTC](https://discuss.elastic.co/t/proper-buckets-path-value-for-a-filters-aggregation/57754/4 "2017-07-05T22:28:19Z")