Adjust knn query cancellation checks to use collector patter (#132515)

Author: benwtrent

server/src/main/java/org/elasticsearch/index/codec/vectors/IVFVectorsReader.java

@@ -22,7 +22,6 @@
 import org.apache.lucene.index.VectorEncoding;
 import org.apache.lucene.index.VectorSimilarityFunction;
 import org.apache.lucene.internal.hppc.IntObjectHashMap;
-import org.apache.lucene.search.AbstractKnnCollector;
 import org.apache.lucene.search.KnnCollector;
 import org.apache.lucene.store.ChecksumIndexInput;
 import org.apache.lucene.store.DataInput;
@@ -232,8 +231,6 @@ public final void search(String field, float[] target, KnnCollector knnCollector
             }
             return visitedDocs.getAndSet(docId) == false;
         };
-        assert knnCollector instanceof AbstractKnnCollector;
-        AbstractKnnCollector knnCollectorImpl = (AbstractKnnCollector) knnCollector;
         int nProbe = DYNAMIC_NPROBE;
         // Search strategy may be null if this is being called from checkIndex (e.g. from a test)
         if (knnCollector.getSearchStrategy() instanceof IVFKnnSearchStrategy ivfSearchStrategy) {
@@ -259,7 +256,8 @@ public final void search(String field, float[] target, KnnCollector knnCollector
         // Note, numCollected is doing the bare minimum here.
         // TODO do we need to handle nested doc counts similarly to how we handle
         // filtering? E.g. keep exploring until we hit an expected number of parent documents vs. child vectors?
-        while (centroidIterator.hasNext() && (centroidsVisited < nProbe || knnCollectorImpl.numCollected() < knnCollector.k())) {
+        while (centroidIterator.hasNext()
+            && (centroidsVisited < nProbe || knnCollector.minCompetitiveSimilarity() == Float.NEGATIVE_INFINITY)) {
             ++centroidsVisited;
             // todo do we actually need to know the score???
             long offset = centroidIterator.nextPostingListOffset();

server/src/main/java/org/elasticsearch/search/internal/ExitableDirectoryReader.java

@@ -26,7 +26,6 @@
 import org.apache.lucene.search.KnnCollector;
 import org.apache.lucene.search.VectorScorer;
 import org.apache.lucene.search.suggest.document.CompletionTerms;
-import org.apache.lucene.util.BitSet;
 import org.apache.lucene.util.Bits;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.automaton.CompiledAutomaton;
@@ -146,7 +145,7 @@ public void searchNearestVectors(String field, byte[] target, KnnCollector colle
                 in.searchNearestVectors(field, target, collector, acceptDocs);
                 return;
             }
-            in.searchNearestVectors(field, target, collector, createTimeOutCheckingBits(acceptDocs));
+            in.searchNearestVectors(field, target, new TimeOutCheckingKnnCollector(collector), acceptDocs);
         }
 
         @Override
@@ -164,122 +163,25 @@ public void searchNearestVectors(String field, float[] target, KnnCollector coll
                 in.searchNearestVectors(field, target, collector, acceptDocs);
                 return;
             }
-            in.searchNearestVectors(field, target, collector, createTimeOutCheckingBits(acceptDocs));
+            in.searchNearestVectors(field, target, new TimeOutCheckingKnnCollector(collector), acceptDocs);
         }
 
-        private Bits createTimeOutCheckingBits(Bits acceptDocs) {
-            if (acceptDocs == null || acceptDocs instanceof BitSet) {
-                return new TimeOutCheckingBitSet((BitSet) acceptDocs);
-            }
-            return new TimeOutCheckingBits(acceptDocs);
-        }
-
-        private class TimeOutCheckingBitSet extends BitSet {
-            private static final int MAX_CALLS_BEFORE_QUERY_TIMEOUT_CHECK = 10;
-            private int calls;
-            private final BitSet inner;
-            private final int maxDoc;
-
-            private TimeOutCheckingBitSet(BitSet inner) {
-                this.inner = inner;
-                this.maxDoc = maxDoc();
-            }
-
-            @Override
-            public void set(int i) {
-                throw new UnsupportedOperationException("not supported on TimeOutCheckingBitSet");
-            }
-
-            @Override
-            public boolean getAndSet(int i) {
-                throw new UnsupportedOperationException("not supported on TimeOutCheckingBitSet");
-            }
-
-            @Override
-            public void clear(int i) {
-                throw new UnsupportedOperationException("not supported on TimeOutCheckingBitSet");
-            }
-
-            @Override
-            public void clear(int startIndex, int endIndex) {
-                throw new UnsupportedOperationException("not supported on TimeOutCheckingBitSet");
-            }
-
-            @Override
-            public int cardinality() {
-                if (inner == null) {
-                    return maxDoc;
-                }
-                return inner.cardinality();
-            }
-
-            @Override
-            public int approximateCardinality() {
-                if (inner == null) {
-                    return maxDoc;
-                }
-                return inner.approximateCardinality();
-            }
-
-            @Override
-            public int prevSetBit(int index) {
-                throw new UnsupportedOperationException("not supported on TimeOutCheckingBitSet");
-            }
-
-            @Override
-            public int nextSetBit(int start, int end) {
-                throw new UnsupportedOperationException("not supported on TimeOutCheckingBitSet");
-            }
-
-            @Override
-            public long ramBytesUsed() {
-                throw new UnsupportedOperationException("not supported on TimeOutCheckingBitSet");
-            }
-
-            @Override
-            public boolean get(int index) {
-                if (calls++ % MAX_CALLS_BEFORE_QUERY_TIMEOUT_CHECK == 0) {
-                    queryCancellation.checkCancelled();
-                }
-                if (inner == null) {
-                    // if acceptDocs is null, we assume all docs are accepted
-                    return index >= 0 && index < maxDoc;
-                }
-                return inner.get(index);
-            }
-
-            @Override
-            public int length() {
-                if (inner == null) {
-                    // if acceptDocs is null, we assume all docs are accepted
-                    return maxDoc;
-                }
-                return 0;
-            }
-        }
-
-        private class TimeOutCheckingBits implements Bits {
+        private class TimeOutCheckingKnnCollector extends KnnCollector.Decorator {
+            private final KnnCollector in;
             private static final int MAX_CALLS_BEFORE_QUERY_TIMEOUT_CHECK = 10;
-            private final Bits updatedAcceptDocs;
             private int calls;
 
-            private TimeOutCheckingBits(Bits acceptDocs) {
-                // when acceptDocs is null due to no doc deleted, we will instantiate a new one that would
-                // match all docs to allow timeout checking.
-                this.updatedAcceptDocs = acceptDocs == null ? new Bits.MatchAllBits(maxDoc()) : acceptDocs;
+            private TimeOutCheckingKnnCollector(KnnCollector in) {
+                super(in);
+                this.in = in;
             }
 
             @Override
-            public boolean get(int index) {
+            public boolean collect(int docId, float similarity) {
                 if (calls++ % MAX_CALLS_BEFORE_QUERY_TIMEOUT_CHECK == 0) {
                     queryCancellation.checkCancelled();
                 }
-                return updatedAcceptDocs.get(index);
-            }
-
-            @Override
-            public int length() {
-                return updatedAcceptDocs.length();
+                return in.collect(docId, similarity);
             }
         }
     }