Remove FilteredHnswGraphSearcher

Author: carlosdelest

server/src/main/java/org/elasticsearch/index/codec/vectors/es910/hnsw/FilteredHnswGraphSearcher.java

@@ -21,7 +21,6 @@
 
 import org.apache.lucene.search.KnnCollector;
 import org.apache.lucene.search.TopKnnCollector;
-import org.apache.lucene.search.knn.KnnSearchStrategy;
 import org.apache.lucene.util.BitSet;
 import org.apache.lucene.util.Bits;
 import org.apache.lucene.util.FixedBitSet;
@@ -56,77 +55,6 @@ public HnswGraphSearcher(NeighborQueue candidates, BitSet visited) {
         this.visited = visited;
     }
 
-    /**
-     * See {@link HnswGraphSearcher#search(RandomVectorScorer, KnnCollector, HnswGraph, Bits, int)}
-     *
-     * @param scorer the scorer to compare the query with the nodes
-     * @param knnCollector a hnsw knn collector of top knn results to be returned
-     * @param graph the graph values. May represent the entire graph, or a level in a hierarchical
-     *     graph.
-     * @param acceptOrds {@link Bits} that represents the allowed document ordinals to match, or
-     *     {@code null} if they are all allowed to match.
-     */
-    public static void search(RandomVectorScorer scorer, KnnCollector knnCollector, HnswGraph graph, Bits acceptOrds) throws IOException {
-        int filteredDocCount = 0;
-        if (acceptOrds instanceof BitSet bitSet) {
-            // Use approximate cardinality as this is good enough, but ensure we don't exceed the graph
-            // size as that is illogical
-            filteredDocCount = Math.min(bitSet.approximateCardinality(), graph.size());
-        }
-        search(scorer, knnCollector, graph, acceptOrds, filteredDocCount);
-    }
-
-    /**
-     * Searches the HNSW graph for the nearest neighbors of a query vector. If entry points are
-     * directly provided via the knnCollector, then the search will be initialized at those points.
-     * Otherwise, the search will discover the best entry point per the normal HNSW search algorithm.
-     *
-     * @param scorer the scorer to compare the query with the nodes
-     * @param knnCollector a hnsw knn collector of top knn results to be returned
-     * @param graph the graph values. May represent the entire graph, or a level in a hierarchical
-     *     graph.
-     * @param acceptOrds {@link Bits} that represents the allowed document ordinals to match, or
-     *     {@code null} if they are all allowed to match.
-     * @param filteredDocCount the number of docs that pass the filter
-     */
-    public static void search(RandomVectorScorer scorer, KnnCollector knnCollector, HnswGraph graph, Bits acceptOrds, int filteredDocCount)
-        throws IOException {
-        assert filteredDocCount >= 0 && filteredDocCount <= graph.size();
-        KnnSearchStrategy.Hnsw hnswStrategy;
-        if (knnCollector.getSearchStrategy() instanceof KnnSearchStrategy.Hnsw hnsw) {
-            hnswStrategy = hnsw;
-        } else if (knnCollector.getSearchStrategy() instanceof KnnSearchStrategy.Seeded seeded
-            && seeded.originalStrategy() instanceof KnnSearchStrategy.Hnsw hnsw) {
-                hnswStrategy = hnsw;
-            } else {
-                hnswStrategy = KnnSearchStrategy.Hnsw.DEFAULT;
-            }
-        final AbstractHnswGraphSearcher innerSearcher;
-        // First, check if we should use a filtered searcher
-        if (acceptOrds != null
-            // We can only use filtered search if we know the maxConn
-            && graph.maxConn() != HnswGraph.UNKNOWN_MAX_CONN
-            && filteredDocCount > 0
-            && hnswStrategy.useFilteredSearch((float) filteredDocCount / graph.size())) {
-            innerSearcher = FilteredHnswGraphSearcher.create(knnCollector.k(), graph, filteredDocCount, acceptOrds);
-        } else {
-            innerSearcher = new HnswGraphSearcher(new NeighborQueue(knnCollector.k(), true), new SparseFixedBitSet(getGraphSize(graph)));
-        }
-        // Then, check if we the search strategy is seeded
-        final AbstractHnswGraphSearcher graphSearcher;
-        if (knnCollector.getSearchStrategy() instanceof KnnSearchStrategy.Seeded seeded && seeded.numberOfEntryPoints() > 0) {
-            graphSearcher = SeededHnswGraphSearcher.fromEntryPoints(
-                innerSearcher,
-                seeded.numberOfEntryPoints(),
-                seeded.entryPoints(),
-                graph.size()
-            );
-        } else {
-            graphSearcher = innerSearcher;
-        }
-        graphSearcher.search(knnCollector, scorer, graph, acceptOrds);
-    }
-
     /**
      * Search {@link OnHeapHnswGraph}, this method is thread safe.
      *