- Direct Known Subclasses:
KnnByteVectorQuery
,KnnFloatVectorQuery
KnnVectorsReader.search(java.lang.String, float[], org.apache.lucene.search.KnnCollector, org.apache.lucene.util.Bits)
to perform nearest neighbour search.
This query also allows for performing a kNN search subject to a filter. In this case, it first executes the filter for each leaf, then chooses a strategy dynamically:
- If the filter cost is less than k, just execute an exact search
- Otherwise run a kNN search subject to the filter
- If the kNN search visits too many vectors without completing, stop and run an exact search
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Nested Class Summary
Nested ClassesModifier and TypeClassDescription(package private) static class
Caches the results of a KnnVector search: a list of docs and their scores -
Field Summary
Fields -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionprotected abstract TopDocs
approximateSearch
(LeafReaderContext context, Bits acceptDocs, int visitedLimit, KnnCollectorManager knnCollectorManager) private BitSet
createBitSet
(DocIdSetIterator iterator, Bits liveDocs, int maxDoc) private Query
createRewrittenQuery
(IndexReader reader, TopDocs topK) (package private) abstract VectorScorer
createVectorScorer
(LeafReaderContext context, FieldInfo fi) boolean
Override and implement query instance equivalence properly in a subclass.protected TopDocs
exactSearch
(LeafReaderContext context, DocIdSetIterator acceptIterator, QueryTimeout queryTimeout) (package private) static int[]
findSegmentStarts
(List<LeafReaderContext> leaves, int[] docs) getField()
int
getK()
protected KnnCollectorManager
getKnnCollectorManager
(int k, IndexSearcher searcher) private TopDocs
getLeafResults
(LeafReaderContext ctx, Weight filterWeight, TimeLimitingKnnCollectorManager timeLimitingKnnCollectorManager) int
hashCode()
Override and implement query hash code properly in a subclass.protected TopDocs
mergeLeafResults
(TopDocs[] perLeafResults) Merges all segment-level kNN results to get the index-level kNN results.rewrite
(IndexSearcher indexSearcher) Expert: called to re-write queries into primitive queries.private TopDocs
searchLeaf
(LeafReaderContext ctx, Weight filterWeight, TimeLimitingKnnCollectorManager timeLimitingKnnCollectorManager) void
visit
(QueryVisitor visitor) Recurse through the query tree, visiting any child queries.Methods inherited from class org.apache.lucene.search.Query
classHash, createWeight, sameClassAs, toString, toString
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Field Details
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NO_RESULTS
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field
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k
protected final int k -
filter
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Constructor Details
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AbstractKnnVectorQuery
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Method Details
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rewrite
Description copied from class:Query
Expert: called to re-write queries into primitive queries. For example, a PrefixQuery will be rewritten into a BooleanQuery that consists of TermQuerys.Callers are expected to call
rewrite
multiple times if necessary, until the rewritten query is the same as the original query.The rewrite process may be able to make use of IndexSearcher's executor and be executed in parallel if the executor is provided.
- Overrides:
rewrite
in classQuery
- Throws:
IOException
- See Also:
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searchLeaf
private TopDocs searchLeaf(LeafReaderContext ctx, Weight filterWeight, TimeLimitingKnnCollectorManager timeLimitingKnnCollectorManager) throws IOException - Throws:
IOException
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getLeafResults
private TopDocs getLeafResults(LeafReaderContext ctx, Weight filterWeight, TimeLimitingKnnCollectorManager timeLimitingKnnCollectorManager) throws IOException - Throws:
IOException
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createBitSet
private BitSet createBitSet(DocIdSetIterator iterator, Bits liveDocs, int maxDoc) throws IOException - Throws:
IOException
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getKnnCollectorManager
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approximateSearch
protected abstract TopDocs approximateSearch(LeafReaderContext context, Bits acceptDocs, int visitedLimit, KnnCollectorManager knnCollectorManager) throws IOException - Throws:
IOException
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createVectorScorer
abstract VectorScorer createVectorScorer(LeafReaderContext context, FieldInfo fi) throws IOException - Throws:
IOException
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exactSearch
protected TopDocs exactSearch(LeafReaderContext context, DocIdSetIterator acceptIterator, QueryTimeout queryTimeout) throws IOException - Throws:
IOException
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mergeLeafResults
Merges all segment-level kNN results to get the index-level kNN results.The default implementation delegates to
TopDocs.merge(int, TopDocs[])
to find the overall topk
, which requires input results to be sorted.This method is useful for reading and / or modifying the final results as needed.
- Parameters:
perLeafResults
- array of segment-level kNN results.- Returns:
- index-level kNN results (no constraint on their ordering).
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createRewrittenQuery
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findSegmentStarts
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visit
Description copied from class:Query
Recurse through the query tree, visiting any child queries. -
equals
Description copied from class:Query
Override and implement query instance equivalence properly in a subclass. This is required so thatQueryCache
works properly.Typically a query will be equal to another only if it's an instance of the same class and its document-filtering properties are identical to those of the other instance. Utility methods are provided for certain repetitive code.
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hashCode
public int hashCode()Description copied from class:Query
Override and implement query hash code properly in a subclass. This is required so thatQueryCache
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getField
- Returns:
- the knn vector field where the knn vector search happens.
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getK
public int getK()- Returns:
- the max number of results the KnnVector search returns.
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getFilter
- Returns:
- the filter that is executed before the KnnVector search happens. Only the results accepted by this filter are returned by the KnnVector search.
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