Elasticsearch terms stats query not grouping correctly - search

Question

I have a terms stats query very similar to this one:
Sum Query in Elasticsearch
However, my key_field is a date.
I was expecting to receive results grouped by the full key_field value ["2014-01-20", "2014-01-21", "2014-01-22"] but it appears to be splitting the key field when it encounters a "-". What I received is actually grouped by ["2014", "01", "20", "21", "22"].
Why is it splitting my key?

Answer 1

You probably have your key_field mapped with a string-type using the standard-analyzer.
That'll tokenize 2014-01-20 into 2014, 01, and 20.
You probably want to index your date as having type date. You can also have it as a string without analyzing it.
Here's a runnable example you can play with: https://www.found.no/play/gist/5eb6b8d176e1cc72c9b8
#!/bin/bash
export ELASTICSEARCH_ENDPOINT="http://localhost:9200"
# Create indexes
curl -XPUT "$ELASTICSEARCH_ENDPOINT/play" -d '{
"settings": {},
"mappings": {
"type": {
"properties": {
"date_as_a_string": {
"type": "string"
},
"date_as_nonanalyzed_string": {
"type": "string",
"index": "not_analyzed"
}
}
}
}
}'
# Index documents
curl -XPOST "$ELASTICSEARCH_ENDPOINT/_bulk?refresh=true" -d '
{"index":{"_index":"play","_type":"type"}}
{"date":"2014-01-01T00:00:00.000Z","date_as_a_string":"2014-01-01T00:00:00.000Z","date_as_nonanalyzed_string":"2014-01-01T00:00:00.000Z","x":42}
'
# Do searches
curl -XPOST "$ELASTICSEARCH_ENDPOINT/_search?pretty" -d '
{
"facets": {
"date": {
"terms_stats": {
"key_field": "date",
"value_field": "x"
}
},
"date_as_a_string": {
"terms_stats": {
"key_field": "date_as_a_string",
"value_field": "x"
}
},
"date_as_nonanalyzed_string": {
"terms_stats": {
"key_field": "date_as_nonanalyzed_string",
"value_field": "x"
}
}
},
"size": 0
}
'