Query DSL¶

Nixiesearch has a Lucene-inspired query DSL with multiple search operators.

To search over a field, make sure that this field is marked as searchable in index mapping.

Search operators¶

Currently three search operators are supported:

match: search over a single field
multi_match: search over multiple fields
match_all: match all documents

All search operators can be combined with filters to search over a subset of documents.

match¶

Match query can be written in two JSON formats. A full version:

{
  "query": {
    "match": {
      "<field-name>": {
        "query": "<search-query>",
        "operator": "or",
        "threshold": 0.666
      }
    }
  }
}

Or a shorter version:

{
  "query": {
    "match": {
      "<field-name>": "<search-query>"
    }
  }
}

Where:

<field-name>: is an existing field marked as searchable.
<search-query>: a search query string.
operator: optional, possible values: "and", "or". Default is "or". For lexical search, should documents contain all or some of the terms from the search query. For semantic search this parameter is ignored.
threshold: optional, a cosine similarity threshold

multi_match¶

An operator similar to match but able to search multiple fields at once:

{
  "query": {
    "multi_match": {
      "fields": ["<field-name>", "<field-name>"],
      "query": "<search-query>",
      "operator": "and"
    }
  }
}

Where:

<field-name>: is an existing field marked as searchable.
<search-query>: a search query string.
operator: optional, possible values: "and", "or". For lexical search, should documents contain all or some of terms from the search query. For semantic search this parameter is ignored.

Compared to Lucene-based search engines, Nixiesearch does a RRF mixing of documents matched over different fields:

At first pass, documents matching each separate field are collected.
At next step N separate per-field search results are merged together into a single ranking.

This approach allows mixing search results made over multiple fields of different underlying search types, e.g. combining lexical and semantic search over N fields.

match_all¶

A search operator matching all documents in an index. Useful when combining with filters to search over a subset of documents.

{
  "query": {
    "match_all": {}
  }
}

match_all operator has no parameters.

Wildcard field queries¶

To allow more dynamism in index schema, you can use * wildcard placeholder in field names:

schema:
  movies:
    extra_*:
      type: text
      search:
        type: lexical
        language: en

So all fields matching the wildcard pattern are going to be treated according to the schema. Wildcard fields have minor limitations:

only a single * placeholder is allowed.
you cannot have a non-wildcard field defined matching a wildcard pattern (e.g. having both a regular title_string field and a wildcard *_string in the same index).

To search over a wildcard field, you have to use the exact field name:

{
  "query": {
    "match": {
      "extra_title": "<search-query>"
    }
  }
}

Although it's possible to use wildcard placeholders in retrieval fields:

{
  "query": {
    "match_all": {}
  },
  "fields": ["extra_*"]
}

Which will return all fields stored for a document matching the extra_* wildcard pattern.