Logsdb and source only snapshots.

docs/changelog/122199.yaml

@@ -0,0 +1,5 @@
+pr: 122199
+summary: Logsdb and source only snapshots
+area: Logs
+type: bug
+issues: []

server/src/main/java/org/elasticsearch/common/lucene/Lucene.java

@@ -20,6 +20,8 @@
 import org.apache.lucene.index.ConcurrentMergeScheduler;
 import org.apache.lucene.index.CorruptIndexException;
 import org.apache.lucene.index.DirectoryReader;
+import org.apache.lucene.index.FieldInfo;
+import org.apache.lucene.index.FieldInfos;
 import org.apache.lucene.index.FilterCodecReader;
 import org.apache.lucene.index.FilterDirectoryReader;
 import org.apache.lucene.index.FilterLeafReader;
@@ -190,14 +192,24 @@ public static SegmentInfos pruneUnreferencedFiles(String segmentsFileName, Direc
                 throw new IllegalStateException("no commit found in the directory");
             }
         }
+        String parentField = null;
         final IndexCommit cp = getIndexCommit(si, directory);
+        try (var reader = DirectoryReader.open(cp)) {
+            var topLevelFieldInfos = FieldInfos.getMergedFieldInfos(reader);
+            for (FieldInfo fieldInfo : topLevelFieldInfos) {
+                if (fieldInfo.isParentField()) {
+                    parentField = fieldInfo.getName();
+                }
+            }
+        }
         try (
             IndexWriter writer = new IndexWriter(
                 directory,
                 indexWriterConfigWithNoMerging(Lucene.STANDARD_ANALYZER).setSoftDeletesField(Lucene.SOFT_DELETES_FIELD)
                     .setIndexCommit(cp)
                     .setCommitOnClose(false)
                     .setOpenMode(IndexWriterConfig.OpenMode.APPEND)
+                    .setParentField(parentField)
             )
         ) {
             // do nothing and close this will kick off IndexFileDeleter which will remove all pending files

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

@@ -232,7 +232,8 @@ public IndexService(
                 mapperMetrics
             );
             this.indexFieldData = new IndexFieldDataService(indexSettings, indicesFieldDataCache, circuitBreakerService);
-            if (indexSettings.getIndexSortConfig().hasIndexSort()) {
+            boolean sourceOnly = Boolean.parseBoolean(indexSettings.getSettings().get("index.source_only"));
+            if (indexSettings.getIndexSortConfig().hasIndexSort() && sourceOnly == false) {
                 // we delay the actual creation of the sort order for this index because the mapping has not been merged yet.
                 // The sort order is validated right after the merge of the mapping later in the process.
                 this.indexSortSupplier = () -> indexSettings.getIndexSortConfig()

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

@@ -176,7 +176,8 @@ public Builder(
                 true,
                 () -> null,
                 (n, c, o) -> Mode.valueOf(o.toString().toUpperCase(Locale.ROOT)),
-                m -> toType(m).enabled.explicit() ? null : toType(m).mode,
+                // Avoid initializing _source.mode if it doesn't need to be serialized:
+                m -> toType(m).enabled.explicit() ? null : toType(m).serializeMode ? toType(m).mode : null,
                 (b, n, v) -> b.field(n, v.toString().toLowerCase(Locale.ROOT)),
                 v -> v.toString().toLowerCase(Locale.ROOT)
             ).setMergeValidator((previous, current, conflicts) -> (previous == current) || current != Mode.STORED)
@@ -300,10 +301,11 @@ private static SourceFieldMapper resolveStaticInstance(final Mode sourceMode) {
         if (indexMode == IndexMode.STANDARD && settingSourceMode == Mode.STORED) {
             return DEFAULT;
         }
+        SourceFieldMapper sourceFieldMapper = null;
         if (onOrAfterDeprecateModeVersion(c.indexVersionCreated())) {
-            return resolveStaticInstance(settingSourceMode);
+            sourceFieldMapper = resolveStaticInstance(settingSourceMode);
         } else {
-            return new SourceFieldMapper(
+            sourceFieldMapper = new SourceFieldMapper(
                 settingSourceMode,
                 Explicit.IMPLICIT_TRUE,
                 Strings.EMPTY_ARRAY,
@@ -312,6 +314,10 @@ private static SourceFieldMapper resolveStaticInstance(final Mode sourceMode) {
                 c.indexVersionCreated().onOrAfter(IndexVersions.SOURCE_MAPPER_MODE_ATTRIBUTE_NOOP)
             );
         }
+        // By default no attributes are specified and so the Builder doesn't get used.
+        // Need to validate the returned instance based on index mode:
+        indexMode.validateSourceFieldMapper(sourceFieldMapper);
+        return sourceFieldMapper;
     },
         c -> new Builder(
             c.getIndexSettings().getMode(),

server/src/test/java/org/elasticsearch/index/mapper/SourceFieldMapperTests.java

@@ -267,14 +267,14 @@ public void testSyntheticSourceInTimeSeries() throws IOException {
         });
         DocumentMapper mapper = createTimeSeriesModeDocumentMapper(mapping);
         assertTrue(mapper.sourceMapper().isSynthetic());
-        assertEquals("{\"_source\":{}}", mapper.sourceMapper().toString());
+        assertEquals("{}", mapper.sourceMapper().toString());
     }
 
     public void testSyntheticSourceWithLogsIndexMode() throws IOException {
         XContentBuilder mapping = fieldMapping(b -> { b.field("type", "keyword"); });
         DocumentMapper mapper = createLogsModeDocumentMapper(mapping);
         assertTrue(mapper.sourceMapper().isSynthetic());
-        assertEquals("{\"_source\":{}}", mapper.sourceMapper().toString());
+        assertEquals("{}", mapper.sourceMapper().toString());
     }
 
     public void testSupportsNonDefaultParameterValues() throws IOException {

x-pack/plugin/core/src/main/java/org/elasticsearch/snapshots/sourceonly/SourceOnlySnapshot.java

@@ -9,6 +9,7 @@
 import org.apache.lucene.codecs.Codec;
 import org.apache.lucene.index.CheckIndex;
 import org.apache.lucene.index.DirectoryReader;
+import org.apache.lucene.index.DocValuesSkipIndexType;
 import org.apache.lucene.index.DocValuesType;
 import org.apache.lucene.index.FieldInfo;
 import org.apache.lucene.index.FieldInfos;
@@ -252,7 +253,7 @@ private SegmentCommitInfo syncSegment(
                             false,
                             IndexOptions.NONE,
                             DocValuesType.NONE,
-                            fieldInfo.docValuesSkipIndexType(),
+                            DocValuesSkipIndexType.NONE,
                             -1,
                             fieldInfo.attributes(),
                             0,