104 lines
3.1 KiB
Plaintext
104 lines
3.1 KiB
Plaintext
[[query-dsl-has-parent-query]]
|
|
=== Has Parent Query
|
|
|
|
The `has_parent` query accepts a query and a parent type. The query is
|
|
executed in the parent document space, which is specified by the parent
|
|
type. This query returns child documents which associated parents have
|
|
matched. For the rest `has_parent` query has the same options and works
|
|
in the same manner as the `has_child` query.
|
|
|
|
[source,js]
|
|
--------------------------------------------------
|
|
GET /_search
|
|
{
|
|
"query": {
|
|
"has_parent" : {
|
|
"parent_type" : "blog",
|
|
"query" : {
|
|
"term" : {
|
|
"tag" : "something"
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
--------------------------------------------------
|
|
// CONSOLE
|
|
|
|
Note that the `has_parent` is a slow query compared to other queries in the
|
|
query dsl due to the fact that it performs a join. The performance degrades
|
|
as the number of matching parent documents increases. If you care about query
|
|
performance you should not use this query. However if you do happen to use
|
|
this query then use it as less as possible. Each `has_parent` query that gets
|
|
added to a search request can increase query time significantly.
|
|
|
|
[float]
|
|
==== Scoring capabilities
|
|
|
|
The `has_parent` also has scoring support. The default is `false` which
|
|
ignores the score from the parent document. The score is in this
|
|
case equal to the boost on the `has_parent` query (Defaults to 1). If
|
|
the score is set to `true`, then the score of the matching parent
|
|
document is aggregated into the child documents belonging to the
|
|
matching parent document. The score mode can be specified with the
|
|
`score` field inside the `has_parent` query:
|
|
|
|
[source,js]
|
|
--------------------------------------------------
|
|
GET /_search
|
|
{
|
|
"query": {
|
|
"has_parent" : {
|
|
"parent_type" : "blog",
|
|
"score" : true,
|
|
"query" : {
|
|
"term" : {
|
|
"tag" : "something"
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
--------------------------------------------------
|
|
// CONSOLE
|
|
|
|
[float]
|
|
==== Ignore Unmapped
|
|
|
|
When set to `true` the `ignore_unmapped` option will ignore an unmapped `type`
|
|
and will not match any documents for this query. This can be useful when
|
|
querying multiple indexes which might have different mappings. When set to
|
|
`false` (the default value) the query will throw an exception if the `type`
|
|
is not mapped.
|
|
|
|
[float]
|
|
==== Sorting
|
|
|
|
Child documents can't be sorted by fields in matching parent documents via the
|
|
regular sort options. If you need to sort child documents by field in the parent
|
|
documents then you should use the `function_score` query and then just sort
|
|
by `_score`.
|
|
|
|
Sorting tags by parent document' `view_count` field:
|
|
|
|
[source,js]
|
|
--------------------------------------------------
|
|
GET /_search
|
|
{
|
|
"query": {
|
|
"has_parent" : {
|
|
"parent_type" : "blog",
|
|
"score" : true,
|
|
"query" : {
|
|
"function_score" : {
|
|
"script_score": {
|
|
"script": "_score * doc['view_count'].value"
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
--------------------------------------------------
|
|
// CONSOLE
|