Allow random sampling

src/main/java/it/cavallium/dbengine/lucene/collector/DecimalBucketMultiCollectorManager.java

@@ -13,11 +13,13 @@ import org.apache.lucene.facet.Facets;
 import org.apache.lucene.facet.FacetsCollector;
 import org.apache.lucene.facet.FacetsCollectorManager;
 import org.apache.lucene.facet.LabelAndValue;
+import org.apache.lucene.facet.RandomSamplingFacetsCollector;
 import org.apache.lucene.facet.range.DoubleRange;
 import org.apache.lucene.facet.range.DoubleRangeFacetCounts;
 import org.apache.lucene.facet.range.LongRange;
 import org.apache.lucene.facet.range.LongRangeFacetCounts;
 import org.apache.lucene.facet.range.Range;
+import org.apache.lucene.search.Collector;
 import org.apache.lucene.search.CollectorManager;
 import org.apache.lucene.search.DoubleValuesSource;
 import org.apache.lucene.search.IndexSearcher;
@@ -31,8 +33,12 @@ import org.jetbrains.annotations.Nullable;
 
 public class DecimalBucketMultiCollectorManager implements CollectorMultiManager<Buckets, Buckets> {
 
+	private final FacetsCollectorManager facetsCollectorManager;
+	private final Range[] bucketRanges;
+
 	private final List<Query> queries;
 	private final Query normalizationQuery;
+	private final @Nullable Integer sampleSize;
 
 	private final String bucketField;
 	private final BucketValueSource bucketValueSource;
@@ -43,8 +49,6 @@ public class DecimalBucketMultiCollectorManager implements CollectorMultiManager
 	private final double maximum;
 	private final int buckets;
 
-	private final Range[] bucketRanges;
-
 	// todo: replace with an argument
 	private static final boolean USE_LONGS = true;
 
@@ -54,7 +58,8 @@ public class DecimalBucketMultiCollectorManager implements CollectorMultiManager
 			String bucketField,
 			BucketValueSource bucketValueSource,
 			List<Query> queries,
-			Query normalizationQuery) {
+			Query normalizationQuery,
+			@Nullable Integer sampleSize) {
 		this.queries = queries;
 		this.normalizationQuery = normalizationQuery;
 		var bucketsInt = (int) Math.ceil(buckets);
@@ -65,6 +70,7 @@ public class DecimalBucketMultiCollectorManager implements CollectorMultiManager
 		this.totalLength = bucketLength * bucketsInt;
 		this.bucketField = bucketField;
 		this.bucketValueSource = bucketValueSource;
+		this.sampleSize = sampleSize;
 
 		if (USE_LONGS) {
 			this.bucketRanges = new LongRange[bucketsInt];
@@ -90,6 +96,17 @@ public class DecimalBucketMultiCollectorManager implements CollectorMultiManager
 				);
 			}
 		}
+
+		this.facetsCollectorManager = new FacetsCollectorManager() {
+			@Override
+			public FacetsCollector newCollector() throws IOException {
+				if (sampleSize != null) {
+					return new RandomSamplingFacetsCollector(sampleSize);
+				} else {
+					return super.newCollector();
+				}
+			}
+		};
 	}
 
 	public double[] newBuckets() {
@@ -97,7 +114,8 @@ public class DecimalBucketMultiCollectorManager implements CollectorMultiManager
 	}
 
 	public Buckets search(IndexSearcher indexSearcher) throws IOException {
-		var facetsCollectorManager = new FacetsCollectorManager();
+		//var facetsCollector = facetsCollectorManager.newCollector();
+		//FacetsCollector.search(indexSearcher, normalizationQuery, 10, facetsCollector);
 		var facetsCollector = indexSearcher.search(normalizationQuery, facetsCollectorManager);
 		double[] reducedNormalizationBuckets = newBuckets();
 		List<DoubleArrayList> seriesReducedBuckets = new ArrayList<>(queries.size());
@@ -112,6 +130,7 @@ public class DecimalBucketMultiCollectorManager implements CollectorMultiManager
 			if (USE_LONGS) {
 				LongValuesSource valuesSource;
 				if (bucketValueSource instanceof NullValueSource) {
+
 					valuesSource = null;
 				} else if (bucketValueSource instanceof ConstantValueSource constantValueSource) {
 					valuesSource = LongValuesSource.constant(constantValueSource.constant().longValue());
@@ -144,7 +163,7 @@ public class DecimalBucketMultiCollectorManager implements CollectorMultiManager
 						(DoubleRange[]) bucketRanges
 				);
 			}
-			FacetResult children = facets.getTopChildren(100, bucketField);
+			FacetResult children = facets.getTopChildren(0, bucketField);
 			for (LabelAndValue labelAndValue : children.labelValues) {
 				var index = Integer.parseInt(labelAndValue.label);
 				reducedBuckets.set(index, reducedBuckets.getDouble(index) + labelAndValue.value.doubleValue());
@@ -167,7 +186,7 @@ public class DecimalBucketMultiCollectorManager implements CollectorMultiManager
 			normalizationFacets = new LongRangeFacetCounts(bucketField,
 					valuesSource,
 					facetsCollector,
-					null,
+					normalizationQuery,
 					(LongRange[]) bucketRanges
 			);
 		} else {
@@ -184,7 +203,7 @@ public class DecimalBucketMultiCollectorManager implements CollectorMultiManager
 			normalizationFacets = new DoubleRangeFacetCounts(bucketField,
 					valuesSource,
 					facetsCollector,
-					null,
+					normalizationQuery,
 					(DoubleRange[]) bucketRanges
 			);
 		}

src/main/java/it/cavallium/dbengine/lucene/searcher/BucketParams.java

@@ -2,6 +2,7 @@ package it.cavallium.dbengine.lucene.searcher;
 
 import it.cavallium.dbengine.lucene.collector.BucketValueSource;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 public record BucketParams(double min, double max, int buckets, String bucketFieldName,
-													 @NotNull BucketValueSource valueSource) {}
+													 @NotNull BucketValueSource valueSource, @Nullable Integer sampleSize) {}

src/main/java/it/cavallium/dbengine/lucene/searcher/DecimalBucketMultiSearcher.java

@@ -45,7 +45,8 @@ public class DecimalBucketMultiSearcher {
 							bucketParams.bucketFieldName(),
 							bucketParams.valueSource(),
 							queries,
-							normalizationQuery
+							normalizationQuery,
+							bucketParams.sampleSize()
 					);
 				})
 				.flatMap(cmm -> Flux