ES|QL: Score all docs in a single getOutput call in LuceneTopNSourceOperator (#136172)

Author: ioanatia

x-pack/plugin/esql/compute/src/main/java/org/elasticsearch/compute/lucene/LuceneTopNSourceOperator.java

@@ -21,8 +21,6 @@
 import org.apache.lucene.search.TopScoreDocCollectorManager;
 import org.apache.lucene.util.RamUsageEstimator;
 import org.elasticsearch.common.Strings;
-import org.elasticsearch.common.breaker.CircuitBreaker;
-import org.elasticsearch.compute.data.BlockFactory;
 import org.elasticsearch.compute.data.DocBlock;
 import org.elasticsearch.compute.data.DocVector;
 import org.elasticsearch.compute.data.DoubleBlock;
@@ -42,6 +40,7 @@
 import java.util.Arrays;
 import java.util.List;
 import java.util.Optional;
+import java.util.concurrent.TimeUnit;
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
@@ -91,8 +90,7 @@ public Factory(
         public SourceOperator get(DriverContext driverContext) {
             return new LuceneTopNSourceOperator(
                 contexts,
-                driverContext.breaker(),
-                driverContext.blockFactory(),
+                driverContext,
                 maxPageSize,
                 sorts,
                 estimatedPerRowSortSize,
@@ -126,7 +124,10 @@ public String describe() {
     // We use the same value as the INITIAL_INTERVAL from CancellableBulkScorer
     private static final int NUM_DOCS_INTERVAL = 1 << 12;
 
-    private final CircuitBreaker breaker;
+    // The max time we should be spending scoring docs in one getOutput call, before we return to update the driver status
+    private static final long MAX_EXEC_TIME = TimeUnit.SECONDS.toNanos(1);
+
+    private final DriverContext driverContext;
     private final List<SortBuilder<?>> sorts;
     private final long estimatedPerRowSortSize;
     private final int limit;
@@ -151,22 +152,21 @@ public String describe() {
 
     public LuceneTopNSourceOperator(
         List<? extends ShardContext> contexts,
-        CircuitBreaker breaker,
-        BlockFactory blockFactory,
+        DriverContext driverContext,
         int maxPageSize,
         List<SortBuilder<?>> sorts,
         long estimatedPerRowSortSize,
         int limit,
         LuceneSliceQueue sliceQueue,
         boolean needsScore
     ) {
-        super(contexts, blockFactory, maxPageSize, sliceQueue);
-        this.breaker = breaker;
+        super(contexts, driverContext.blockFactory(), maxPageSize, sliceQueue);
+        this.driverContext = driverContext;
         this.sorts = sorts;
         this.estimatedPerRowSortSize = estimatedPerRowSortSize;
         this.limit = limit;
         this.needsScore = needsScore;
-        breaker.addEstimateBytesAndMaybeBreak(reserveSize(), "esql lucene topn");
+        driverContext.breaker().addEstimateBytesAndMaybeBreak(reserveSize(), "esql lucene topn");
     }
 
     @Override
@@ -201,34 +201,49 @@ public Page getCheckedOutput() throws IOException {
 
     private Page collect() throws IOException {
         assert doneCollecting == false;
+        long start = System.nanoTime();
+
         var scorer = getCurrentOrLoadNextScorer();
-        if (scorer == null) {
-            doneCollecting = true;
-            startEmitting();
-            return emit();
-        }
-        try {
+
+        while (scorer != null) {
             if (scorer.tags().isEmpty() == false) {
                 throw new UnsupportedOperationException("tags not supported by " + getClass());
             }
-            if (perShardCollector == null || perShardCollector.shardContext.index() != scorer.shardContext().index()) {
-                // TODO: share the bottom between shardCollectors
-                perShardCollector = newPerShardCollector(scorer.shardContext(), sorts, needsScore, limit);
+
+            try {
+                if (perShardCollector == null || perShardCollector.shardContext.index() != scorer.shardContext().index()) {
+                    // TODO: share the bottom between shardCollectors
+                    perShardCollector = newPerShardCollector(scorer.shardContext(), sorts, needsScore, limit);
+                }
+                var leafCollector = perShardCollector.getLeafCollector(scorer.leafReaderContext());
+                scorer.scoreNextRange(leafCollector, scorer.leafReaderContext().reader().getLiveDocs(), NUM_DOCS_INTERVAL);
+            } catch (CollectionTerminatedException cte) {
+                // Lucene terminated early the collection (doing topN for an index that's sorted and the topN uses the same sorting)
+                scorer.markAsDone();
+            }
+
+            // check if the query has been cancelled.
+            driverContext.checkForEarlyTermination();
+
+            if (scorer.isDone()) {
+                var nextScorer = getCurrentOrLoadNextScorer();
+                if (nextScorer != null && nextScorer.shardContext().index() != scorer.shardContext().index()) {
+                    startEmitting();
+                    return emit();
+                }
+                scorer = nextScorer;
             }
-            var leafCollector = perShardCollector.getLeafCollector(scorer.leafReaderContext());
-            scorer.scoreNextRange(leafCollector, scorer.leafReaderContext().reader().getLiveDocs(), NUM_DOCS_INTERVAL);
-        } catch (CollectionTerminatedException cte) {
-            // Lucene terminated early the collection (doing topN for an index that's sorted and the topN uses the same sorting)
-            scorer.markAsDone();
-        }
-        if (scorer.isDone()) {
-            var nextScorer = getCurrentOrLoadNextScorer();
-            if (nextScorer == null || nextScorer.shardContext().index() != scorer.shardContext().index()) {
-                startEmitting();
-                return emit();
+
+            // When it takes a long time to start emitting pages we need to return back to the driver so we can update its status.
+            // Even if this should almost never happen, we want to update the driver status even when a query runs "forever".
+            if (System.nanoTime() - start > MAX_EXEC_TIME) {
+                return null;
             }
         }
-        return null;
+
+        doneCollecting = true;
+        startEmitting();
+        return emit();
     }
 
     private boolean isEmitting() {
@@ -348,7 +363,7 @@ protected void describe(StringBuilder sb) {
 
     @Override
     protected void additionalClose() {
-        Releasables.close(() -> breaker.addWithoutBreaking(-reserveSize()));
+        Releasables.close(() -> driverContext.breaker().addWithoutBreaking(-reserveSize()));
     }
 
     private long reserveSize() {