[Test] Randomly disable doc values skippers in time-series indices

modules/data-streams/src/internalClusterTest/java/org/elasticsearch/datastreams/TSDBSyntheticIdsIT.java

@@ -1221,6 +1221,9 @@ private static void putDataStreamTemplate(String indexPattern, int primaries, in
         } else if (rarely()) {
             settings.put(IndexSettings.INDEX_MAPPER_SOURCE_MODE_SETTING.getKey(), SourceFieldMapper.Mode.STORED);
         }
+        if (rarely()) {
+            settings.put(IndexSettings.USE_DOC_VALUES_SKIPPER.getKey(), false);
+        }
         settings.put(extraSettings);
 
         final var mappings = """

server/src/main/java/org/elasticsearch/index/codec/tsdb/TSDBSyntheticIdDocValuesHolder.java

@@ -10,13 +10,15 @@
 package org.elasticsearch.index.codec.tsdb;
 
 import org.apache.lucene.codecs.DocValuesProducer;
+import org.apache.lucene.index.DocValuesSkipIndexType;
 import org.apache.lucene.index.DocValuesSkipper;
 import org.apache.lucene.index.FieldInfo;
 import org.apache.lucene.index.FieldInfos;
 import org.apache.lucene.index.SortedDocValues;
 import org.apache.lucene.index.SortedNumericDocValues;
 import org.apache.lucene.search.DocIdSetIterator;
 import org.apache.lucene.util.BytesRef;
+import org.elasticsearch.core.Nullable;
 import org.elasticsearch.index.mapper.TimeSeriesRoutingHashFieldMapper;
 import org.elasticsearch.index.mapper.TsidExtractingIdFieldMapper;
 import org.elasticsearch.index.mapper.Uid;
@@ -39,6 +41,8 @@ class TSDBSyntheticIdDocValuesHolder {
     private final FieldInfo timestampFieldInfo;
     private final FieldInfo routingHashFieldInfo;
     private final DocValuesProducer docValuesProducer;
+    private final boolean hasTsIdSkipper;
+    private final boolean hasTimestampSkipper;
 
     private SortedNumericDocValues timestampDocValues; // sorted desc. order
     private SortedDocValues routingHashDocValues; // sorted asc. order
@@ -52,6 +56,8 @@ class TSDBSyntheticIdDocValuesHolder {
         this.timestampFieldInfo = safeFieldInfo(fieldInfos, TSDBSyntheticIdPostingsFormat.TIMESTAMP);
         this.routingHashFieldInfo = safeFieldInfo(fieldInfos, TSDBSyntheticIdPostingsFormat.TS_ROUTING_HASH);
         this.docValuesProducer = docValuesProducer;
+        this.hasTsIdSkipper = tsIdFieldInfo.docValuesSkipIndexType() != DocValuesSkipIndexType.NONE;
+        this.hasTimestampSkipper = timestampFieldInfo.docValuesSkipIndexType() != DocValuesSkipIndexType.NONE;
     }
 
     private FieldInfo safeFieldInfo(FieldInfos fieldInfos, String fieldName) {
@@ -178,6 +184,9 @@ BytesRef lookupTsIdOrd(int tsIdOrdinal) throws IOException {
      * @throws IOException if any I/O exception occurs
      */
     private int findStartDocIDForTsIdOrd(int tsIdOrd) throws IOException {
+        if (hasTsIdSkipper == false) {
+            return 0;
+        }
         var skipper = docValuesProducer.getSkipper(tsIdFieldInfo);
         assert skipper != null;
         if (skipper.minValue() > tsIdOrd || tsIdOrd > skipper.maxValue()) {
@@ -265,7 +274,11 @@ int findFirstDocWithTsIdOrdinalEqualTo(int tsIdOrd) throws IOException {
         return DocIdSetIterator.NO_MORE_DOCS;
     }
 
+    @Nullable
     DocValuesSkipper docValuesSkipperForTimestamp() throws IOException {
+        if (hasTimestampSkipper == false) {
+            return null;
+        }
         var skipper = docValuesProducer.getSkipper(timestampFieldInfo);
         assert skipper != null;
         return skipper;

server/src/main/java/org/elasticsearch/index/codec/tsdb/TSDBSyntheticIdFieldsProducer.java

@@ -232,40 +232,44 @@ public SeekStatus seekCeil(BytesRef id) throws IOException {
             final long timestamp = TsidExtractingIdFieldMapper.extractTimestampFromSyntheticId(id);
 
             // Use doc values skipper on timestamp to early exit or skip to the first document matching the timestamp
+            int nextDocID;
             var skipper = docValues.docValuesSkipperForTimestamp();
-            if (timestamp > skipper.maxValue()) {
-                // timestamp is greater than the global maximum value in the segment, so the first docID matching the _tsid is guaranteed to
-                // have a smaller timestamp that the one we're looking for and we can early exit at the current docID position. Note that
-                // synthetic ids are generated so that the resulting array of bytes has a natural order that reflects the order of docs in
-                // the segment (_tsid asc then @timestamp desc). So if timestamp > skipper.maxValue(), it means that the next doc has a
-                // @timestamp smaller than what we're looking for.
-                docID = firstDocID;
-                docTsIdOrd = tsIdOrd;
-                docTimestamp = null;
-                return SeekStatus.NOT_FOUND;
-            }
-            if (skipper.minValue() > timestamp) {
-                // timestamp is smaller than the global minimum value in the segment, so no docs matching the _tsid will also match the
-                // timestamp, so we can early exit at the position of the next _tsid (if there is such one).
-                int nextDocTsIdOrd = tsIdOrd + 1;
-                if (nextDocTsIdOrd < docValues.getTsIdValueCount()) {
-                    docID = docValues.findFirstDocWithTsIdOrdinalEqualTo(nextDocTsIdOrd);
-                    docTsIdOrd = nextDocTsIdOrd;
+            if (skipper != null) {
+                if (timestamp > skipper.maxValue()) {
+                    // timestamp is greater than the global maximum value in the segment, so the first docID matching the _tsid is
+                    // guaranteed to have a smaller timestamp that the one we're looking for and we can early exit at the current docID
+                    // position. Note that synthetic ids are generated so that the resulting array of bytes has a natural order that
+                    // reflects the order of docs in the segment (_tsid asc then @timestamp desc). So if timestamp > skipper.maxValue(),
+                    // it means that the next doc has a @timestamp smaller than what we're looking for.
+                    docID = firstDocID;
+                    docTsIdOrd = tsIdOrd;
                     docTimestamp = null;
                     return SeekStatus.NOT_FOUND;
                 }
-                // no docs/terms to iterate on
-                resetDocID(DocIdSetIterator.NO_MORE_DOCS);
-                return SeekStatus.END;
-            }
-            skipper.advance(firstDocID);
-            skipper.advance(timestamp, Long.MAX_VALUE);
-
-            int nextDocID;
-            if (skipper.minDocID(0) != DocIdSetIterator.NO_MORE_DOCS) {
-                nextDocID = Math.max(firstDocID, skipper.minDocID(0));
+                if (skipper.minValue() > timestamp) {
+                    // timestamp is smaller than the global minimum value in the segment, so no docs matching the _tsid will also match
+                    // the timestamp, so we can early exit at the position of the next _tsid (if there is such one).
+                    int nextDocTsIdOrd = tsIdOrd + 1;
+                    if (nextDocTsIdOrd < docValues.getTsIdValueCount()) {
+                        docID = docValues.findFirstDocWithTsIdOrdinalEqualTo(nextDocTsIdOrd);
+                        docTsIdOrd = nextDocTsIdOrd;
+                        docTimestamp = null;
+                        return SeekStatus.NOT_FOUND;
+                    }
+                    // no docs/terms to iterate on
+                    resetDocID(DocIdSetIterator.NO_MORE_DOCS);
+                    return SeekStatus.END;
+                }
+                skipper.advance(firstDocID);
+                skipper.advance(timestamp, Long.MAX_VALUE);
+
+                if (skipper.minDocID(0) != DocIdSetIterator.NO_MORE_DOCS) {
+                    nextDocID = Math.max(firstDocID, skipper.minDocID(0));
+                } else {
+                    // we exhausted the doc values skipper, scan all docs from first doc matching _tsid
+                    nextDocID = firstDocID;
+                }
             } else {
-                // we exhausted the doc values skipper, scan all docs from first doc matching _tsid
                 nextDocID = firstDocID;
             }
             int nextDocTsIdOrd = tsIdOrd;

server/src/test/java/org/elasticsearch/index/codec/tsdb/TSDBSyntheticIdPostingsFormatTests.java

@@ -503,41 +503,36 @@ private static void runTest(CheckedBiConsumer<IndexWriter, TestDocParser, IOExce
      * Builds time-series index settings.
      */
     private static IndexSettings buildIndexSettings(final String indexName) {
-        return new IndexSettings(
-            IndexMetadata.builder(indexName)
-                .settings(
-                    indexSettings(IndexVersion.current(), 1, 0).put(IndexSettings.SYNTHETIC_ID.getKey(), true)
-                        .put(IndexSettings.MODE.getKey(), IndexMode.TIME_SERIES.getName())
-                        .putList(IndexMetadata.INDEX_DIMENSIONS.getKey(), List.of("hostname", "metric.field"))
-                        .build()
-                )
-                .putMapping("""
-                    {
+        var settings = indexSettings(IndexVersion.current(), 1, 0).put(IndexSettings.SYNTHETIC_ID.getKey(), true)
+            .put(IndexSettings.MODE.getKey(), IndexMode.TIME_SERIES.getName())
+            .putList(IndexMetadata.INDEX_DIMENSIONS.getKey(), List.of("hostname", "metric.field"));
+        if (rarely()) {
+            settings.put(IndexSettings.USE_DOC_VALUES_SKIPPER.getKey(), false);
+        }
+        return new IndexSettings(IndexMetadata.builder(indexName).settings(settings.build()).putMapping("""
+            {
+                "properties": {
+                    "@timestamp": {
+                        "type": "date"
+                    },
+                    "hostname": {
+                        "type": "keyword",
+                        "time_series_dimension": true
+                    },
+                    "metric": {
                         "properties": {
-                            "@timestamp": {
-                                "type": "date"
-                            },
-                            "hostname": {
+                            "field": {
                                 "type": "keyword",
                                 "time_series_dimension": true
                             },
-                            "metric": {
-                                "properties": {
-                                    "field": {
-                                        "type": "keyword",
-                                        "time_series_dimension": true
-                                    },
-                                    "value": {
-                                        "type": "integer",
-                                        "time_series_metric": "counter"
-                                    }
-                                }
+                            "value": {
+                                "type": "integer",
+                                "time_series_metric": "counter"
                             }
                         }
-                    }""")
-                .build(),
-            Settings.EMPTY
-        );
+                    }
+                }
+            }""").build(), Settings.EMPTY);
     }
 
     /**