Change index.mapping.use_doc_values_skipper default setting to true (elastic#134221)

TSBD and LogsDB indexes with this setting set to true do not use backing indexes
for `host.name`, `_tsid` or `@timestamp` fields, and instead enable sparse indexes
on their doc_values fields.

This was originally added and set to default to `true` a while back, but was then changed 
to default to `false` when performance suffered. Changes to lucene, and the addition of 
filter-by-filter optimizations on skipper queries, means that performance looks more 
acceptable now.

This is still gated behind a feature flag so that we can measure the behaviour in nightly
benchmarks before enabling for public use.

Author: romseygeek

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

@@ -671,7 +671,7 @@ public boolean isES87TSDBCodecEnabled() {
     public static final boolean DOC_VALUES_SKIPPER = new FeatureFlag("doc_values_skipper").isEnabled();
     public static final Setting<Boolean> USE_DOC_VALUES_SKIPPER = Setting.boolSetting(
         "index.mapping.use_doc_values_skipper",
-        false,
+        true,
         Property.IndexScope,
         Property.Final
     );

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

@@ -191,6 +191,7 @@ private static Version parseUnchecked(String version) {
     public static final IndexVersion UPGRADE_TO_LUCENE_10_3_1 = def(9_041_0_00, Version.LUCENE_10_3_1);
 
     public static final IndexVersion REENABLED_TIMESTAMP_DOC_VALUES_SPARSE_INDEX = def(9_042_0_00, Version.LUCENE_10_3_1);
+    public static final IndexVersion SKIPPERS_ENABLED_BY_DEFAULT = def(9_043_0_00, Version.LUCENE_10_3_1);
 
     /*
      * STOP! READ THIS FIRST! No, really,

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

@@ -1100,7 +1100,7 @@ private DateFieldMapper(
      * Determines whether the doc values skipper (sparse index) should be used for the {@code @timestamp} field.
      * <p>
      * The doc values skipper is enabled only if {@code index.mapping.use_doc_values_skipper} is set to {@code true},
-     * the index was created on or after {@link IndexVersions#REENABLED_TIMESTAMP_DOC_VALUES_SPARSE_INDEX}, and the
+     * the index was created on or after {@link IndexVersions#SKIPPERS_ENABLED_BY_DEFAULT}, and the
      * field has doc values enabled. Additionally, the index mode must be {@link IndexMode#LOGSDB} or {@link IndexMode#TIME_SERIES}, and
      * the index sorting configuration must include the {@code @timestamp} field.
      *
@@ -1109,9 +1109,8 @@ private DateFieldMapper(
      * @param fullFieldName  The full name of the field being checked, expected to be {@code @timestamp}.
      * @return {@code true} if the doc values skipper should be used, {@code false} otherwise.
      */
-
     private static boolean shouldUseDocValuesSkipper(IndexSettings indexSettings, boolean hasDocValues, final String fullFieldName) {
-        return indexSettings.getIndexVersionCreated().onOrAfter(IndexVersions.REENABLED_TIMESTAMP_DOC_VALUES_SPARSE_INDEX)
+        return indexSettings.getIndexVersionCreated().onOrAfter(IndexVersions.SKIPPERS_ENABLED_BY_DEFAULT)
             && indexSettings.useDocValuesSkipper()
             && hasDocValues
             && (IndexMode.LOGSDB.equals(indexSettings.getMode()) || IndexMode.TIME_SERIES.equals(indexSettings.getMode()))

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

@@ -515,7 +515,7 @@ private static FieldType resolveFieldType(
                     assert hasDocValues.getValue();
                     return new FieldType(Defaults.FIELD_TYPE_WITH_SKIP_DOC_VALUES);
                 }
-                if (indexCreatedVersion.onOrAfter(IndexVersions.HOSTNAME_DOC_VALUES_SPARSE_INDEX)
+                if (indexCreatedVersion.onOrAfter(IndexVersions.SKIPPERS_ENABLED_BY_DEFAULT)
                     && shouldUseDocValuesSkipper(hasDocValues.getValue(), indexSortConfig, indexMode, fullFieldName)) {
                     return new FieldType(Defaults.FIELD_TYPE_WITH_SKIP_DOC_VALUES);
                 }

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

@@ -60,7 +60,7 @@ public static TimeSeriesIdFieldMapper getInstance(boolean useDocValuesSkipper) {
     }
 
     public static TimeSeriesIdFieldMapper getInstance(MappingParserContext context) {
-        boolean useDocValuesSkipper = context.indexVersionCreated().onOrAfter(IndexVersions.TIME_SERIES_ID_DOC_VALUES_SPARSE_INDEX)
+        boolean useDocValuesSkipper = context.indexVersionCreated().onOrAfter(IndexVersions.SKIPPERS_ENABLED_BY_DEFAULT)
             && context.getIndexSettings().useDocValuesSkipper();
         return TimeSeriesIdFieldMapper.getInstance(useDocValuesSkipper);
     }