Move index sorting defaults to IndexSettingProviders

rest-api-spec/src/yamlRestTest/resources/rest-api-spec/test/logsdb/10_settings.yml

@@ -276,7 +276,7 @@ override sort order settings:
                 type: text
 
   - match: { error.type: "illegal_argument_exception" }
-  - match: { error.reason: "index.sort.fields:[] index.sort.order:[asc, asc], size mismatch" }
+  - match: { error.reason: "index.sort.field:[] index.sort.order:[asc, asc], size mismatch" }
 
 ---
 override sort missing settings:
@@ -312,7 +312,7 @@ override sort missing settings:
                 type: text
 
   - match: { error.type: "illegal_argument_exception" }
-  - match: { error.reason: "index.sort.fields:[] index.sort.missing:[_last, _first], size mismatch" }
+  - match: { error.reason: "index.sort.field:[] index.sort.missing:[_last, _first], size mismatch" }
 
 ---
 override sort mode settings:
@@ -348,7 +348,7 @@ override sort mode settings:
                 type: text
 
   - match: { error.type: "illegal_argument_exception" }
-  - match: { error.reason: "index.sort.fields:[] index.sort.mode:[MAX, MAX], size mismatch" }
+  - match: { error.reason: "index.sort.field:[] index.sort.mode:[MAX, MAX], size mismatch" }
 
 ---
 override sort field using nested field type in sorting:

rest-api-spec/src/yamlRestTest/resources/rest-api-spec/test/tsdb/10_settings.yml

@@ -576,3 +576,29 @@ check time_series empty time bound value:
           "@timestamp": "2021-09-26T03:09:52.123456789Z",
           "metricset": "pod"
         }
+
+---
+default sort field:
+  - requires:
+      cluster_features: ["gte_v8.1.0"]
+      reason: introduced in 8.1.0
+
+  - do:
+      indices.create:
+        index: test_index
+        body:
+          settings:
+            index:
+              mode: time_series
+              routing_path: foo
+              time_series:
+                start_time: 2021-04-28T00:00:00Z
+                end_time: 2021-04-29T00:00:00Z
+
+  - do:
+      indices.get_settings:
+        index: test_index
+        include_defaults: true
+  - match: { .test_index.settings.index.mode: time_series }
+  - match: { .test_index.settings.index.sort.field: [ "_tsid", "@timestamp" ] }
+  - match: { .test_index.settings.index.sort.order: [ "asc", "desc" ] }

server/src/main/java/org/elasticsearch/index/IndexMode.java

@@ -38,6 +38,7 @@
 import org.elasticsearch.index.mapper.TimeSeriesIdFieldMapper;
 import org.elasticsearch.index.mapper.TimeSeriesRoutingHashFieldMapper;
 import org.elasticsearch.index.mapper.TsidExtractingIdFieldMapper;
+import org.elasticsearch.search.sort.SortOrder;
 
 import java.io.IOException;
 import java.time.Instant;
@@ -402,7 +403,7 @@ public SourceFieldMapper.Mode defaultSourceMode() {
         }
     };
 
-    static final String HOST_NAME = "host.name";
+    public static final String HOST_NAME = "host.name";
 
     private static void validateRoutingPathSettings(Map<Setting<?>, Object> settings) {
         settingRequiresTimeSeries(settings, IndexMetadata.INDEX_ROUTING_PATH);
@@ -451,8 +452,6 @@ private static CompressedXContent createDefaultMapping(boolean includeHostName)
     }
 
     private static final List<Setting<?>> TIME_SERIES_UNSUPPORTED = List.of(
-        IndexSortConfig.INDEX_SORT_FIELD_SETTING,
-        IndexSortConfig.INDEX_SORT_ORDER_SETTING,
         IndexSortConfig.INDEX_SORT_MODE_SETTING,
         IndexSortConfig.INDEX_SORT_MISSING_SETTING
     );
@@ -639,6 +638,32 @@ public void provideAdditionalSettings(
             }
             if (indexMode == LOOKUP) {
                 additionalSettings.put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1);
+            } else if (indexMode == TIME_SERIES) {
+                var sortFields = List.of(TimeSeriesIdFieldMapper.NAME, DataStreamTimestampFieldMapper.DEFAULT_PATH);
+                var sortOrder = List.of(SortOrder.ASC, SortOrder.DESC);
+
+                if (IndexSortConfig.INDEX_SORT_FIELD_SETTING.exists(indexTemplateAndCreateRequestSettings)) {
+                    if (IndexSortConfig.INDEX_SORT_FIELD_SETTING.get(indexTemplateAndCreateRequestSettings).equals(sortFields) == false) {
+                        throw new IllegalArgumentException(
+                            tsdbMode() + " is incompatible with [" + IndexSortConfig.INDEX_SORT_FIELD_SETTING.getKey() + "]"
+                        );
+                    }
+                } else {
+                    additionalSettings.putList(IndexSortConfig.INDEX_SORT_FIELD_SETTING.getKey(), sortFields);
+                }
+
+                if (IndexSortConfig.INDEX_SORT_ORDER_SETTING.exists(indexTemplateAndCreateRequestSettings)) {
+                    if (IndexSortConfig.INDEX_SORT_ORDER_SETTING.get(indexTemplateAndCreateRequestSettings).equals(sortOrder) == false) {
+                        throw new IllegalArgumentException(
+                            tsdbMode() + " is incompatible with [" + IndexSortConfig.INDEX_SORT_ORDER_SETTING.getKey() + "]"
+                        );
+                    }
+                } else {
+                    additionalSettings.putList(
+                        IndexSortConfig.INDEX_SORT_ORDER_SETTING.getKey(),
+                        sortOrder.stream().map(Object::toString).toList()
+                    );
+                }
             }
         }
     }

server/src/main/java/org/elasticsearch/index/IndexSortConfig.java

@@ -102,25 +102,6 @@ public final class IndexSortConfig {
         Setting.Property.ServerlessPublic
     );
 
-    public static final FieldSortSpec[] TIME_SERIES_SORT, TIMESTAMP_SORT, HOSTNAME_TIMESTAMP_SORT, HOSTNAME_TIMESTAMP_BWC_SORT;
-    static {
-        FieldSortSpec timeStampSpec = new FieldSortSpec(DataStreamTimestampFieldMapper.DEFAULT_PATH);
-        timeStampSpec.order = SortOrder.DESC;
-        TIME_SERIES_SORT = new FieldSortSpec[] { new FieldSortSpec(TimeSeriesIdFieldMapper.NAME), timeStampSpec };
-        TIMESTAMP_SORT = new FieldSortSpec[] { timeStampSpec };
-
-        FieldSortSpec hostnameSpec = new FieldSortSpec(IndexMode.HOST_NAME);
-        hostnameSpec.order = SortOrder.ASC;
-        hostnameSpec.missingValue = "_last";
-        hostnameSpec.mode = MultiValueMode.MIN;
-        HOSTNAME_TIMESTAMP_SORT = new FieldSortSpec[] { hostnameSpec, timeStampSpec };
-
-        // Older indexes use ascending ordering for host name and timestamp.
-        HOSTNAME_TIMESTAMP_BWC_SORT = new FieldSortSpec[] {
-            new FieldSortSpec(IndexMode.HOST_NAME),
-            new FieldSortSpec(DataStreamTimestampFieldMapper.DEFAULT_PATH) };
-    }
-
     private static String validateMissingValue(String missing) {
         if ("_last".equals(missing) == false && "_first".equals(missing) == false) {
             throw new IllegalArgumentException("Illegal missing value:[" + missing + "], " + "must be one of [_last, _first]");
@@ -146,6 +127,85 @@ private static MultiValueMode parseMultiValueMode(String value) {
         return mode;
     }
 
+    private static void checkSizeMismatch(String firstKey, List<?> first, String secondKey, List<?> second) {
+        if (first.size() != second.size()) {
+            throw new IllegalArgumentException(firstKey + ":" + first + " " + secondKey + ":" + second + ", size mismatch");
+        }
+    }
+
+    public static void validateSortSettings(Settings settings) {
+        List<String> fields = INDEX_SORT_FIELD_SETTING.get(settings);
+
+        if (INDEX_SORT_ORDER_SETTING.exists(settings)) {
+            var order = INDEX_SORT_ORDER_SETTING.get(settings);
+            checkSizeMismatch(INDEX_SORT_FIELD_SETTING.getKey(), fields, INDEX_SORT_ORDER_SETTING.getKey(), order);
+        }
+
+        if (INDEX_SORT_MODE_SETTING.exists(settings)) {
+            var mode = INDEX_SORT_MODE_SETTING.get(settings);
+            checkSizeMismatch(INDEX_SORT_FIELD_SETTING.getKey(), fields, INDEX_SORT_MODE_SETTING.getKey(), mode);
+        }
+
+        if (INDEX_SORT_MISSING_SETTING.exists(settings)) {
+            var missing = INDEX_SORT_MISSING_SETTING.get(settings);
+            checkSizeMismatch(INDEX_SORT_FIELD_SETTING.getKey(), fields, INDEX_SORT_MISSING_SETTING.getKey(), missing);
+        }
+    }
+
+    public static class LegacyIndexSortConfigDefaults {
+        public static final FieldSortSpec[] TIME_SERIES_SORT, TIMESTAMP_SORT, HOSTNAME_TIMESTAMP_SORT, HOSTNAME_TIMESTAMP_BWC_SORT;
+
+        static {
+            FieldSortSpec timeStampSpec = new FieldSortSpec(DataStreamTimestampFieldMapper.DEFAULT_PATH);
+            timeStampSpec.order = SortOrder.DESC;
+            TIME_SERIES_SORT = new FieldSortSpec[] { new FieldSortSpec(TimeSeriesIdFieldMapper.NAME), timeStampSpec };
+            TIMESTAMP_SORT = new FieldSortSpec[] { timeStampSpec };
+
+            FieldSortSpec hostnameSpec = new FieldSortSpec(IndexMode.HOST_NAME);
+            hostnameSpec.order = SortOrder.ASC;
+            hostnameSpec.missingValue = "_last";
+            hostnameSpec.mode = MultiValueMode.MIN;
+            HOSTNAME_TIMESTAMP_SORT = new FieldSortSpec[] { hostnameSpec, timeStampSpec };
+
+            // Older indexes use ascending ordering for host name and timestamp.
+            HOSTNAME_TIMESTAMP_BWC_SORT = new FieldSortSpec[] {
+                new FieldSortSpec(IndexMode.HOST_NAME),
+                new FieldSortSpec(DataStreamTimestampFieldMapper.DEFAULT_PATH) };
+        }
+
+        public static FieldSortSpec[] getLegacyDefaultSortSpecs(IndexSettings indexSettings) {
+            var version = indexSettings.getIndexVersionCreated();
+            if (version.onOrAfter(IndexVersions.EXPLICIT_INDEX_SORTING_DEFAULTS)) {
+                return null;
+            }
+
+            final Settings settings = indexSettings.getSettings();
+
+            IndexMode indexMode = indexSettings.getMode();
+            if (indexMode == IndexMode.TIME_SERIES) {
+                return TIME_SERIES_SORT;
+            } else if (indexMode == IndexMode.LOGSDB) {
+                if (INDEX_SORT_FIELD_SETTING.exists(settings)) {
+                    return null;
+                }
+
+                validateSortSettings(settings);
+
+                if (version.onOrAfter(IndexVersions.LOGSB_OPTIONAL_SORTING_ON_HOST_NAME)
+                    || version.between(
+                        IndexVersions.LOGSB_OPTIONAL_SORTING_ON_HOST_NAME_BACKPORT,
+                        IndexVersions.UPGRADE_TO_LUCENE_10_0_0
+                    )) {
+                    return (IndexSettings.LOGSDB_SORT_ON_HOST_NAME.get(settings)) ? HOSTNAME_TIMESTAMP_SORT : TIMESTAMP_SORT;
+                } else {
+                    return HOSTNAME_TIMESTAMP_BWC_SORT;
+                }
+            }
+
+            return null;
+        }
+    }
+
     // visible for tests
     final FieldSortSpec[] sortSpecs;
     private final IndexVersion indexCreatedVersion;
@@ -158,34 +218,13 @@ public IndexSortConfig(IndexSettings indexSettings) {
         this.indexName = indexSettings.getIndex().getName();
         this.indexMode = indexSettings.getMode();
 
-        if (indexMode == IndexMode.TIME_SERIES) {
-            sortSpecs = TIME_SERIES_SORT;
+        var legacyDefaultSortSpecs = LegacyIndexSortConfigDefaults.getLegacyDefaultSortSpecs(indexSettings);
+        if (legacyDefaultSortSpecs != null) {
+            this.sortSpecs = legacyDefaultSortSpecs;
             return;
         }
 
         List<String> fields = INDEX_SORT_FIELD_SETTING.get(settings);
-        if (indexMode == IndexMode.LOGSDB && INDEX_SORT_FIELD_SETTING.exists(settings) == false) {
-            if (INDEX_SORT_ORDER_SETTING.exists(settings)) {
-                var order = INDEX_SORT_ORDER_SETTING.get(settings);
-                throw new IllegalArgumentException("index.sort.fields:" + fields + " index.sort.order:" + order + ", size mismatch");
-            }
-            if (INDEX_SORT_MODE_SETTING.exists(settings)) {
-                var mode = INDEX_SORT_MODE_SETTING.get(settings);
-                throw new IllegalArgumentException("index.sort.fields:" + fields + " index.sort.mode:" + mode + ", size mismatch");
-            }
-            if (INDEX_SORT_MISSING_SETTING.exists(settings)) {
-                var missing = INDEX_SORT_MISSING_SETTING.get(settings);
-                throw new IllegalArgumentException("index.sort.fields:" + fields + " index.sort.missing:" + missing + ", size mismatch");
-            }
-            var version = indexSettings.getIndexVersionCreated();
-            if (version.onOrAfter(IndexVersions.LOGSB_OPTIONAL_SORTING_ON_HOST_NAME)
-                || version.between(IndexVersions.LOGSB_OPTIONAL_SORTING_ON_HOST_NAME_BACKPORT, IndexVersions.UPGRADE_TO_LUCENE_10_0_0)) {
-                sortSpecs = (IndexSettings.LOGSDB_SORT_ON_HOST_NAME.get(settings)) ? HOSTNAME_TIMESTAMP_SORT : TIMESTAMP_SORT;
-            } else {
-                sortSpecs = HOSTNAME_TIMESTAMP_BWC_SORT;
-            }
-            return;
-        }
         sortSpecs = fields.stream().map(FieldSortSpec::new).toArray(FieldSortSpec[]::new);
 
         if (INDEX_SORT_ORDER_SETTING.exists(settings)) {

server/src/main/java/org/elasticsearch/index/IndexVersions.java

@@ -186,6 +186,7 @@ private static Version parseUnchecked(String version) {
     public static final IndexVersion TSID_CREATED_DURING_ROUTING = def(9_037_0_00, Version.LUCENE_10_2_2);
     public static final IndexVersion UPGRADE_TO_LUCENE_10_3_0 = def(9_038_0_00, Version.LUCENE_10_3_0);
     public static final IndexVersion IGNORED_SOURCE_COALESCED_ENTRIES = def(9_039_0_00, Version.LUCENE_10_3_0);
+    public static final IndexVersion EXPLICIT_INDEX_SORTING_DEFAULTS = def(9_040_0_00, Version.LUCENE_10_3_0);
 
     /*
      * STOP! READ THIS FIRST! No, really,

server/src/main/java/org/elasticsearch/index/mapper/MapperFeatures.java

@@ -52,6 +52,7 @@ public class MapperFeatures implements FeatureSpecification {
     static final NodeFeature IGNORED_SOURCE_FIELDS_PER_ENTRY = new NodeFeature("mapper.ignored_source_fields_per_entry");
     public static final NodeFeature MULTI_FIELD_UNICODE_OPTIMISATION_FIX = new NodeFeature("mapper.multi_field.unicode_optimisation_fix");
     static final NodeFeature PATTERN_TEXT_RENAME = new NodeFeature("mapper.pattern_text_rename");
+    static final NodeFeature PROVIDE_INDEX_SORT_SETTING_DEFAULTS = new NodeFeature("mapper.provide_index_sort_setting_defaults");
 
     @Override
     public Set<NodeFeature> getTestFeatures() {
@@ -89,7 +90,8 @@ public Set<NodeFeature> getTestFeatures() {
             IGNORED_SOURCE_FIELDS_PER_ENTRY,
             MULTI_FIELD_UNICODE_OPTIMISATION_FIX,
             MATCH_ONLY_TEXT_BLOCK_LOADER_FIX,
-            PATTERN_TEXT_RENAME
+            PATTERN_TEXT_RENAME,
+            PROVIDE_INDEX_SORT_SETTING_DEFAULTS
         );
     }
 }

server/src/main/java/org/elasticsearch/search/aggregations/support/TimeSeriesIndexSearcher.java

@@ -39,7 +39,7 @@
 import java.util.List;
 import java.util.function.IntSupplier;
 
-import static org.elasticsearch.index.IndexSortConfig.TIME_SERIES_SORT;
+import static org.elasticsearch.index.IndexSortConfig.LegacyIndexSortConfigDefaults.TIME_SERIES_SORT;
 
 /**
  * An IndexSearcher wrapper that executes the searches in time-series indices by traversing them by tsid and timestamp

server/src/test/java/org/elasticsearch/index/IndexSettingsTests.java

@@ -268,6 +268,10 @@ public static IndexMetadata newIndexMeta(String name, Settings indexSettings) {
         return IndexMetadata.builder(name).settings(indexSettings(IndexVersion.current(), 1, 1).put(indexSettings)).build();
     }
 
+    public static IndexMetadata newIndexMeta(String name, Settings indexSettings, IndexVersion indexVersion) {
+        return IndexMetadata.builder(name).settings(indexSettings(indexVersion, 1, 1).put(indexSettings)).build();
+    }
+
     public void testUpdateDurability() {
         IndexMetadata metadata = newIndexMeta(
             "index",