67 lines
1.5 KiB
Plaintext
67 lines
1.5 KiB
Plaintext
[[mapping-index-field]]
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=== `_index` field
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When performing queries across multiple indexes, it is sometimes desirable to
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add query clauses that are associated with documents of only certain indexes.
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The `_index` field allows matching on the index a document was indexed into.
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Its value is accessible in `term`, or `terms` queries, aggregations,
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scripts, and when sorting:
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NOTE: The `_index` is exposed as a virtual field -- it is not added to the
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Lucene index as a real field. This means that you can use the `_index` field
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in a `term` or `terms` query (or any query that is rewritten to a `term`
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query, such as the `match`, `query_string` or `simple_query_string` query),
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but it does not support `prefix`, `wildcard`, `regexp`, or `fuzzy` queries.
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[source,js]
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--------------------------
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# Example documents
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PUT index_1/my_type/1
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{
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"text": "Document in index 1"
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}
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PUT index_2/my_type/2
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{
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"text": "Document in index 2"
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}
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GET index_1,index_2/_search
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{
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"query": {
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"terms": {
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"_index": ["index_1", "index_2"] <1>
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}
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},
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"aggs": {
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"indices": {
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"terms": {
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"field": "_index", <2>
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"size": 10
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}
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}
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},
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"sort": [
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{
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"_index": { <3>
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"order": "asc"
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}
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}
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],
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"script_fields": {
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"index_name": {
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"script": {
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"lang": "painless",
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"inline": "doc['_index']" <4>
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}
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}
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}
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}
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--------------------------
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// CONSOLE
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<1> Querying on the `_index` field
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<2> Aggregating on the `_index` field
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<3> Sorting on the `_index` field
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<4> Accessing the `_index` field in scripts
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