Query

The Query object configures what and how to search. At minimum, provide search text and a max results count.

Constructor

csharp

var query = new Query("search text", maxResults);

Full Configuration

csharp

var query = new Query("search text", maxResults)
{
    EnableCoverage  = true,              // default: true
    CoverageDepth   = 500,               // default: 500
    CoverageSetup   = coverageSetup,     // default: null
    EnableFacets    = false,             // default: false
    EnableBoost     = false,             // default: false
    SortBy          = engine.GetField("rating"), // default: null
    SortAscending   = false,             // default: false
    RemoveDuplicates = true,             // default: true
    Filter          = filter,            // default: null
    Boosts          = boostArray,        // default: null
    FieldBoosts     = new Dictionary<string, float>
    {
        ["title"] = 2.0f                 // multiplies title's Weight; key must be searchable
    },                                   // BM25F mode only, default: null
    KeyExcludeFilter = excludeSet,       // exclude specific document keys
    KeyIncludeFilter = includeSet,       // restrict to specific document keys
    TimeOutLimitMilliseconds = 1000      // default: 1000, max: 10000
};

Properties

Property	Type	Default	Description
`Text`	`string`	`""`	Search text
`MaxNumberOfRecordsToReturn`	`int`	—	Maximum results to return
`EnableCoverage`	`bool`	`true`	Enable coverage-based ranking
`CoverageDepth`	`int`	`500`	How many candidate documents coverage evaluates. Hits beyond the depth are never confirmed, so a count landing exactly on the depth is the cap, not the data — see Deep coverage
`CoverageSetup`	`CoverageSetup?`	`null`	Fine-grained coverage configuration
`EnableFacets`	`bool`	`false`	Return facet counts in the result. Also required for an empty `Text`: without it the empty query is refused, returning an empty `Result` with a `Reason` — see Empty search
`EnableBoost`	`bool`	`false`	Apply boosts defined in `Boosts`
`SortBy`	`Field?`	`null`	Secondary sort field. Score is always the primary key
`SortAscending`	`bool`	`false`	Sort direction when `SortBy` is set
`RemoveDuplicates`	`bool`	`true`	When documents share a foreign key, return only the best-scoring one. Not a group-by on arbitrary fields — see Variants and editions
`Filter`	`Filter?`	`null`	Boolean filter applied before scoring
`Boosts`	`Boost[]?`	`null`	Score boosts applied to matching documents
`FieldBoosts`	`Dictionary<string, float>?`	`null`	Per-query multipliers on each field's `Weight`. Keys must be searchable fields — an unknown or non-searchable key makes `Search` return an empty `Result`. Only applies in BM25F mode
`TimeOutLimitMilliseconds`	`int`	`1000`	Abort scoring after this many milliseconds. Max: 10000

Per-Query Field Boosts

FieldBoosts lets you adjust how much each field counts for one search, without reconfiguring or rebuilding the index.

csharp

// title and description are both Searchable in the field configuration.
var query = new Query("noise cancelling", 10)
{
    FieldBoosts = new Dictionary<string, float>
    {
        ["title"]       = 3.0f,  // 3 × title's Weight
        ["description"] = 0.5f   // half of description's Weight
    }
};

A boost multiplies the field's Weight; it does not replace it. A field with Weight = 2.0f and a boost of 3.0f counts 6×. Fields you leave out keep their Weight (a boost of 1.0). In BM25F terms the boost is folded into the pseudo term-frequency as boost × weight × tf.
Every key must be a searchable field. An unknown or non-searchable key makes Search return an empty Result — no records, and today no Reason either, so it looks like a search that matched nothing. The message is on engine.Status.ErrorMessage. Making a field non-searchable does not remove it from boosts your code still sends.
Boosts only apply in BM25F mode. Check engine.ScoringMode after Index(). The engine uses BM25F when every searchable field has the same BM25k1 (the default); if they differ it scores fields separately and ignores FieldBoosts — valid keys have no effect, and an invalid key still returns an empty result.

Constructors

csharp

Query()

For serializer.

csharp

Query(string queryText, int maxNumberOfRecordsToReturn)

Constructor for the class Query, having default parameters for most of the fields. This query uses the Coverage function, and times out after 1000 ms. To adjust more parameters, set them directly on the instance after creation.

string queryText
int maxNumberOfRecordsToReturn

Properties

Name	Type	Access	Description
Boosts	Boost[]	get/set	is the method to pass the list of boosts to be applied during the search.
CoverageDepth	int	get/set	The number of results from the pattern matcher to be considered by Coverage.
CoverageSetup	CoverageSetup	get/set	Field that controls behavior of the Coverage algorithms. Have no effect for other algorithms.
DocumentsBoosted	int	get	Returns the number of documents that may be boosted in the search.
EnableBoost	bool	get/set	Is used to toggle boosted searches on or off.
EnableCoverage	bool	get/set	Coverage is a function that detects exact matching on tokens in the query, and lifts them up to the top of the result list. If set to false, the search will run with pattern recognition (Relevancy Ranking) only. When Coverage is active, the search result will also return an index number to truncate the list on.
EnableFacets	bool	get/set	Activates calculations of facet histograms in the search results.
FieldBoosts	Dictionary<string, float>	get/set	Per-field BM25F boost factors applied at query time. Key = field name (must match a searchable field name). Value = multiplicative boost for that field's contribution to pseudo_tf. Fields not listed default to 1.0. Typical range: 0.5–3.0. Values below 1.0 de-emphasize a field; values above ~5.0 tend to overwhelm the IDF component and reduce result quality. Example: { "title": 2.0f, "body": 1.0f } doubles the title field's influence.
Filter	Filter	get/set	Is used to pass a filter to the search query.
LogPrefix	string	get/set	If the instance of the search engine has had a logger injected into its constructor, every search will be logged. The log prefix is then first added to the log text, and can be used by the client to add statistical information, for example for use in dashboards.
MaxBoost	int	get/set	Denotes the maximum possible boost that can be assigned. A hit with full boost gets the top score, 65 535; a full unboosted score is 65 535 - MaxBoost · 257.
MaxNumberOfRecordsToReturn	int	get/set	Defines the maximum number of documents to be returned.
RemoveDuplicates	bool	get/set	Removes all duplicates of documents with the same foreign key. Only the one with the best score value is returned in the results list. If foreign keys are not in use, this can be set to null.
SerializedQueryKey	string	get	Serialized key for caching empty search results. Format: F:{filterKey}\|B:{boostFilter1};{strength1},{boostFilter2};{strength2}\|S:{sortField};{asc}\|M:{maxRecords}\|E:{enableFacets}
SortAscending	bool	get/set	Only applicable if SortBy != null.
SortBy	Field	get/set	Use this in order to setup sorting of the results.
Text	string	get/set	Refers to the text (input) to be searched for.
TimeOutLimitMilliseconds	int	get/set	Sets maximum waiting time in case of overloaded CPU. We recommend 1000 ms. Cannot be more than 10000 ms.