Fix: reset the filter built at segment level for date histogram optimization

server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/FilterRewriteIT.java

@@ -0,0 +1,107 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations.bucket;
+
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
+import org.opensearch.action.index.IndexRequestBuilder;
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.time.DateFormatter;
+import org.opensearch.index.query.QueryBuilder;
+import org.opensearch.index.query.QueryBuilders;
+import org.opensearch.search.aggregations.bucket.histogram.DateHistogramInterval;
+import org.opensearch.search.aggregations.bucket.histogram.Histogram;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedDynamicSettingsOpenSearchIntegTestCase;
+
+import java.time.ZoneOffset;
+import java.time.ZonedDateTime;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
+import static org.opensearch.search.aggregations.AggregationBuilders.dateHistogram;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+
+@OpenSearchIntegTestCase.SuiteScopeTestCase
+public class FilterRewriteIT extends ParameterizedDynamicSettingsOpenSearchIntegTestCase {
+
+    // simulate segment level match all
+    private static final QueryBuilder QUERY = QueryBuilders.termQuery("match", true);
+    private static final Map<String, Long> expected = new HashMap<>();
+
+    public FilterRewriteIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected void setupSuiteScopeCluster() throws Exception {
+        assertAcked(client().admin().indices().prepareCreate("idx").get());
+
+        final int segmentCount = randomIntBetween(2, 10);
+        final Set<Long> longTerms = new HashSet();
+
+        final Map<String, Integer> dateTerms = new HashMap<>();
+        for (int i = 0; i < segmentCount; i++) {
+            final List<IndexRequestBuilder> indexRequests = new ArrayList<>();
+
+            long longTerm;
+            do {
+                longTerm = randomInt(segmentCount * 2);
+            } while (!longTerms.add(longTerm));
+            ZonedDateTime time = ZonedDateTime.of(2024, 1, ((int) longTerm % 20) + 1, 0, 0, 0, 0, ZoneOffset.UTC);
+            String dateTerm = DateFormatter.forPattern("yyyy-MM-dd").format(time);
+
+            final int frequency = randomBoolean() ? 1 : randomIntBetween(2, 20);
+            for (int j = 0; j < frequency; j++) {
+                indexRequests.add(
+                    client().prepareIndex("idx")
+                        .setSource(jsonBuilder().startObject().field("date", dateTerm).field("match", true).endObject())
+                );
+            }
+            expected.put(dateTerm + "T00:00:00.000Z", (long) frequency);
+
+            indexRandom(true, false, indexRequests);
+        }
+
+        ensureSearchable();
+    }
+
+    public void testMinDocCountOnDateHistogram() throws Exception {
+        final SearchResponse allResponse = client().prepareSearch("idx")
+            .setSize(0)
+            .setQuery(QUERY)
+            .addAggregation(dateHistogram("histo").field("date").dateHistogramInterval(DateHistogramInterval.DAY).minDocCount(0))
+            .get();
+
+        final Histogram allHisto = allResponse.getAggregations().get("histo");
+        Map<String, Long> results = new HashMap<>();
+        allHisto.getBuckets().forEach(bucket -> results.put(bucket.getKeyAsString(), bucket.getDocCount()));
+
+        for (Map.Entry<String, Long> entry : expected.entrySet()) {
+            assertEquals(entry.getValue(), results.get(entry.getKey()));
+        }
+    }
+}

server/src/main/java/org/opensearch/search/aggregations/bucket/FastFilterRewriteHelper.java

@@ -269,12 +269,15 @@ public void buildFastFilter() throws IOException {
             }
         }
 
-        public void buildFastFilter(LeafReaderContext leaf) throws IOException {
-            assert filters == null : "Filters should only be built once, but they are already built";
-            this.filters = this.aggregationType.buildFastFilter(leaf, context);
+        /**
+         * Built filters for a segment
+         */
+        public Weight[] buildFastFilter(LeafReaderContext leaf) throws IOException {
+            Weight[] filters = this.aggregationType.buildFastFilter(leaf, context);
             if (filters != null) {
                 logger.debug("Fast filter built for shard {} segment {}", context.indexShard().shardId(), leaf.ord);
             }
+            return filters;
         }
     }
 
@@ -340,7 +343,6 @@ public Weight[] buildFastFilter(LeafReaderContext leaf, SearchContext context) t
 
         private Weight[] buildFastFilter(SearchContext context, long[] bounds) throws IOException {
             bounds = processHardBounds(bounds);
-            logger.debug("Bounds are {} for shard {} with hard bound", bounds, context.indexShard().shardId());
             if (bounds == null) {
                 return null;
             }
@@ -447,8 +449,7 @@ public static boolean tryFastFilterAggregation(
                 fastFilterContext.context.indexShard().shardId(),
                 ctx.ord
             );
-            fastFilterContext.buildFastFilter(ctx);
-            filters = fastFilterContext.filters;
+            filters = fastFilterContext.buildFastFilter(ctx);
             if (filters == null) {
                 return false;
             }
@@ -480,20 +481,17 @@ public static boolean tryFastFilterAggregation(
                 incrementDocCount.accept(bucketKey, counts[i]);
                 s++;
                 if (s > size) {
-                    logger.debug("Fast filter optimization applied to composite aggregation with size {}", size);
-                    return true;
+                    break;
                 }
             }
         }
 
-        logger.debug("Fast filter optimization applied");
+        logger.debug("Fast filter optimization applied to shard {} segment {}", fastFilterContext.context.indexShard().shardId(), ctx.ord);
         return true;
     }
 
     private static boolean segmentMatchAll(SearchContext ctx, LeafReaderContext leafCtx) throws IOException {
         Weight weight = ctx.searcher().createWeight(ctx.query(), ScoreMode.COMPLETE_NO_SCORES, 1f);
-        assert weight != null;
-        int count = weight.count(leafCtx);
-        return count > 0 && count == leafCtx.reader().numDocs();
+        return weight != null && weight.count(leafCtx) == leafCtx.reader().numDocs();
     }
 }