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Index
When querying across multiple indexes, you may need to filter results based on the index into which a document was indexed. The index
field matches documents based on their index.
The following example request creates two indexes, products
and customers
, and adds a document to each index:
PUT products/_doc/1
{
"name": "Widget X"
}
PUT customers/_doc/2
{
"name": "John Doe"
}
You can then query both indexes and filter the results using the _index
field, as shown in the following example request:
GET products,customers/_search
{
"query": {
"terms": {
"_index": ["products", "customers"]
}
},
"aggs": {
"index_groups": {
"terms": {
"field": "_index",
"size": 10
}
}
},
"sort": [
{
"_index": {
"order": "desc"
}
}
],
"script_fields": {
"index_name": {
"script": {
"lang": "painless",
"source": "doc['_index'].value"
}
}
}
}
In this example:
- The
query
section uses aterms
query to match documents from theproducts
andcustomers
indexes. - The
aggs
section performs aterms
aggregation on the_index
field, grouping the results by index. - The
sort
section sorts the results by the_index
field in ascending order. - The
script_fields
section adds a new field calledindex_name
to the search results containing the_index
field value for each document.
Querying on the _index
field
The _index
field represents the index into which a document was indexed. You can use this field in your queries to filter, aggregate, sort, or retrieve index information for your search results.
Because the _index
field is automatically added to every document, you can use it in your queries like any other field. For example, you can use the terms
query to match documents from multiple indexes. The following example query returns all documents from the products
and customers
indexes:
{
"query": {
"terms": {
"_index": ["products", "customers"]
}
}
}