Elasticsearch distinct filter values -

i have large document store in elasticsearch , retrieve distinct filter values display on html drop-downs.

an example

[     {         "name": "john doe",         "deparments": [             {                 "name": "accounts"             },             {                 "name": "management"             }         ]     },     {         "name": "jane smith",         "deparments": [             {                 "name": "it"             },             {                 "name": "management"             }         ]     } ]

the drop-down should have list of departments, i.e. it, account , management.

would kind person please point me in right direction retrieving distinct list of departments elasticsearch?

thanks

this job terms aggregation (documentation).

you can have distinct departments values :

post company/employee/_search {   "size":0,   "aggs": {     "by_departments": {       "terms": {         "field": "departments.name",         "size": 0 //see note 1       }     }   } } 

which, in example, outputs :

{    ...    "aggregations": {       "by_departments": {          "buckets": [             {                "key": "management", //see note 2                "doc_count": 2             },             {                "key": "accounts",                "doc_count": 1             },             {                "key": "it",                "doc_count": 1             }          ]       }    } } 

two additional notes :

• setting size 0 set maximum buckets number integer.max_value. don't use if there many departments distinct values.
• you can see keys terms resulting of analyzing departments values. sure use terms aggregation on field mapped not_analyzed .

for example, our default mapping (departments.name analyzed string), adding employee:

{   "name": "bill gates",   "departments": [     {       "name": "it"     },     {       "name": "human resource"     }   ] } 

will cause kind of result:

{    ...    "aggregations": {       "by_departments": {          "buckets": [             {                "key": "it",                "doc_count": 2             },             {                "key": "management",                "doc_count": 2             },             {                "key": "accounts",                "doc_count": 1             },             {                "key": "human",                "doc_count": 1             },             {                "key": "resource",                "doc_count": 1             }          ]       }    } } 

with correct mapping :

post company {   "mappings": {     "employee": {       "properties": {         "name": {           "type": "string"         },         "departments": {           "type": "object",           "properties": {             "name": {               "type": "string",               "index": "not_analyzed"             }           }         }       }     }   } } 

the same request ends outputting :

{    ...    "aggregations": {       "by_departments": {          "buckets": [             {                "key": "it",                "doc_count": 2             },             {                "key": "management",                "doc_count": 2             },             {                "key": "accounts",                "doc_count": 1             },             {                "key": "human resource",                "doc_count": 1             }          ]       }    } } 

hope helps!