Make field limit more predictable

docs/changelog/102885.yaml

@@ -0,0 +1,5 @@
+pr: 102885
+summary: Make field limit more predictable
+area: Mapping
+type: enhancement
+issues: []

modules/legacy-geo/src/test/java/org/elasticsearch/legacygeo/mapper/LegacyGeoShapeFieldMapperTests.java

@@ -76,6 +76,12 @@ protected boolean supportsStoredFields() {
         return false;
     }
 
+    @Override
+    public void testTotalFieldsCount() throws IOException {
+        super.testTotalFieldsCount();
+        assertWarnings("Parameter [strategy] is deprecated and will be removed in a future version");
+    }
+
     @Override
     protected void registerParameters(ParameterChecker checker) throws IOException {
 

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

@@ -330,7 +330,7 @@ public NodeMappingStats getNodeMappingStats() {
         if (mapperService == null) {
             return null;
         }
-        long totalCount = mapperService().mappingLookup().getTotalFieldsCount();
+        long totalCount = mapperService().mappingLookup().getTotalMapperCount();
         long totalEstimatedOverhead = totalCount * 1024L; // 1KiB estimated per mapping
         NodeMappingStats indexNodeMappingStats = new NodeMappingStats(totalCount, totalEstimatedOverhead);
         return indexNodeMappingStats;

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

@@ -113,6 +113,11 @@ public void validate(MappingLookup mappers) {
         }
     }
 
+    @Override
+    public int getTotalFieldsCount() {
+        return 1;
+    }
+
     public static class TypeParser implements Mapper.TypeParser {
         @Override
         public Mapper.Builder parse(String name, Map<String, Object> node, MappingParserContext parserContext)

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

@@ -51,6 +51,7 @@
 import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.function.Supplier;
+import java.util.stream.Stream;
 
 import static org.elasticsearch.core.Strings.format;
 
@@ -428,6 +429,11 @@ protected void doXContentBody(XContentBuilder builder, Params params) throws IOE
 
     protected abstract String contentType();
 
+    @Override
+    public int getTotalFieldsCount() {
+        return 1 + Stream.of(multiFields.mappers).mapToInt(FieldMapper::getTotalFieldsCount).sum();
+    }
+
     public Map<String, NamedAnalyzer> indexAnalyzers() {
         return Map.of();
     }
@@ -455,7 +461,7 @@ private void add(FieldMapper mapper) {
 
             private void update(FieldMapper toMerge, MapperMergeContext context) {
                 if (mapperBuilders.containsKey(toMerge.simpleName()) == false) {
-                    if (context.decrementFieldBudgetIfPossible(toMerge.mapperSize())) {
+                    if (context.decrementFieldBudgetIfPossible(toMerge.getTotalFieldsCount())) {
                         add(toMerge);
                     }
                 } else {

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

@@ -137,16 +137,8 @@ public static FieldType freezeAndDeduplicateFieldType(FieldType fieldType) {
     }
 
     /**
-     * Returns the size this mapper counts against the {@linkplain MapperService#INDEX_MAPPING_TOTAL_FIELDS_LIMIT_SETTING field limit}.
-     * <p>
-     * Needs to be in sync with {@link MappingLookup#getTotalFieldsCount()}.
+     * The total number of fields as defined in the mapping.
+     * Defines how this mapper counts towards {@link MapperService#INDEX_MAPPING_TOTAL_FIELDS_LIMIT_SETTING}.
      */
-    public int mapperSize() {
-        int size = 1;
-        for (Mapper mapper : this) {
-            size += mapper.mapperSize();
-        }
-        return size;
-    }
-
+    public abstract int getTotalFieldsCount();
 }

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

@@ -55,6 +55,7 @@ private CacheKey() {}
     private final List<FieldMapper> indexTimeScriptMappers;
     private final Mapping mapping;
     private final Set<String> completionFields;
+    private final int totalFieldsCount;
 
     /**
      * Creates a new {@link MappingLookup} instance by parsing the provided mapping and extracting its field definitions.
@@ -127,6 +128,7 @@ private MappingLookup(
         Collection<ObjectMapper> objectMappers,
         Collection<FieldAliasMapper> aliasMappers
     ) {
+        this.totalFieldsCount = mapping.getRoot().getTotalFieldsCount();
         this.mapping = mapping;
         Map<String, Mapper> fieldMappers = new HashMap<>();
         Map<String, ObjectMapper> objects = new HashMap<>();
@@ -223,6 +225,14 @@ FieldTypeLookup fieldTypesLookup() {
      * Returns the total number of fields defined in the mappings, including field mappers, object mappers as well as runtime fields.
      */
     public long getTotalFieldsCount() {
+        return totalFieldsCount;
+    }
+
+    /**
+     * Returns the total number of mappers defined in the mappings, including field mappers and their sub-fields
+     * (which are not explicitly defined in the mappings), multi-fields, object mappers, runtime fields and metadata field mappers.
+     */
+    public long getTotalMapperCount() {
         return fieldMappers.size() + objectMappers.size() + runtimeFieldMappersCount;
     }
 
@@ -282,7 +292,7 @@ void checkFieldLimit(long limit, int additionalFieldsToAdd) {
     }
 
     boolean exceedsLimit(long limit, int additionalFieldsToAdd) {
-        return getTotalFieldsCount() + additionalFieldsToAdd - mapping.getSortedMetadataMappers().length > limit;
+        return totalFieldsCount + additionalFieldsToAdd > limit;
     }
 
     private void checkDimensionFieldLimit(long limit) {

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

@@ -182,6 +182,11 @@ public ObjectMapper build(MapperBuilderContext context) {
         }
     }
 
+    @Override
+    public int getTotalFieldsCount() {
+        return 1 + mappers.values().stream().mapToInt(Mapper::getTotalFieldsCount).sum();
+    }
+
     public static class TypeParser implements Mapper.TypeParser {
         @Override
         public boolean supportsVersion(IndexVersion indexCreatedVersion) {
@@ -552,7 +557,7 @@ private static Map<String, Mapper> buildMergedMappers(
 
                 Mapper merged = null;
                 if (mergeIntoMapper == null) {
-                    if (objectMergeContext.decrementFieldBudgetIfPossible(mergeWithMapper.mapperSize())) {
+                    if (objectMergeContext.decrementFieldBudgetIfPossible(mergeWithMapper.getTotalFieldsCount())) {
                         merged = mergeWithMapper;
                     } else if (mergeWithMapper instanceof ObjectMapper om) {
                         merged = truncateObjectMapper(reason, objectMergeContext, om);
@@ -586,7 +591,7 @@ private static ObjectMapper truncateObjectMapper(MergeReason reason, MapperMerge
             // there's not enough capacity for the whole object mapper,
             // so we're just trying to add the shallow object, without it's sub-fields
             ObjectMapper shallowObjectMapper = objectMapper.withoutMappers();
-            if (context.decrementFieldBudgetIfPossible(shallowObjectMapper.mapperSize())) {
+            if (context.decrementFieldBudgetIfPossible(shallowObjectMapper.getTotalFieldsCount())) {
                 // now trying to add the sub-fields one by one via a merge, until we hit the limit
                 return shallowObjectMapper.merge(objectMapper, reason, context);
             }

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

@@ -523,11 +523,7 @@ private static boolean processField(
     }
 
     @Override
-    public int mapperSize() {
-        int size = runtimeFields().size();
-        for (Mapper mapper : this) {
-            size += mapper.mapperSize();
-        }
-        return size;
+    public int getTotalFieldsCount() {
+        return mappers.values().stream().mapToInt(Mapper::getTotalFieldsCount).sum() + runtimeFields.size();
     }
 }

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

@@ -34,7 +34,7 @@ public void testParsing() throws IOException {
         );
         DocumentMapper mapper = createDocumentMapper(mapping);
         assertEquals(mapping, mapper.mappingSource().toString());
-        assertEquals(2, mapper.mapping().getRoot().mapperSize());
+        assertEquals(2, mapper.mapping().getRoot().getTotalFieldsCount());
     }
 
     public void testParsingWithMissingPath() {

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

@@ -213,10 +213,10 @@ public void testMergeWithLimit() {
         final ObjectMapper mergedAdd1 = rootObjectMapper.merge(mergeWith, MapperMergeContext.root(false, false, 1));
 
         // THEN "baz" new field is added to merged mapping
-        assertEquals(3, rootObjectMapper.mapperSize());
-        assertEquals(4, mergeWith.mapperSize());
-        assertEquals(3, mergedAdd0.mapperSize());
-        assertEquals(4, mergedAdd1.mapperSize());
+        assertEquals(3, rootObjectMapper.getTotalFieldsCount());
+        assertEquals(4, mergeWith.getTotalFieldsCount());
+        assertEquals(3, mergedAdd0.getTotalFieldsCount());
+        assertEquals(4, mergedAdd1.getTotalFieldsCount());
     }
 
     public void testMergeWithLimitTruncatedObjectField() {
@@ -231,11 +231,11 @@ public void testMergeWithLimitTruncatedObjectField() {
         ObjectMapper mergedAdd1 = root.merge(mergeWith, MapperMergeContext.root(false, false, 1));
         ObjectMapper mergedAdd2 = root.merge(mergeWith, MapperMergeContext.root(false, false, 2));
         ObjectMapper mergedAdd3 = root.merge(mergeWith, MapperMergeContext.root(false, false, 3));
-        assertEquals(0, root.mapperSize());
-        assertEquals(0, mergedAdd0.mapperSize());
-        assertEquals(1, mergedAdd1.mapperSize());
-        assertEquals(2, mergedAdd2.mapperSize());
-        assertEquals(3, mergedAdd3.mapperSize());
+        assertEquals(0, root.getTotalFieldsCount());
+        assertEquals(0, mergedAdd0.getTotalFieldsCount());
+        assertEquals(1, mergedAdd1.getTotalFieldsCount());
+        assertEquals(2, mergedAdd2.getTotalFieldsCount());
+        assertEquals(3, mergedAdd3.getTotalFieldsCount());
 
         ObjectMapper parent1 = (ObjectMapper) mergedAdd1.getMapper("parent");
         assertNull(parent1.getMapper("child1"));
@@ -262,9 +262,9 @@ public void testMergeSameObjectDifferentFields() {
 
         ObjectMapper mergedAdd0 = root.merge(mergeWith, MapperMergeContext.root(false, false, 0));
         ObjectMapper mergedAdd1 = root.merge(mergeWith, MapperMergeContext.root(false, false, 1));
-        assertEquals(2, root.mapperSize());
-        assertEquals(2, mergedAdd0.mapperSize());
-        assertEquals(3, mergedAdd1.mapperSize());
+        assertEquals(2, root.getTotalFieldsCount());
+        assertEquals(2, mergedAdd0.getTotalFieldsCount());
+        assertEquals(3, mergedAdd1.getTotalFieldsCount());
 
         ObjectMapper parent0 = (ObjectMapper) mergedAdd0.getMapper("parent");
         assertNotNull(parent0.getMapper("child1"));
@@ -285,13 +285,13 @@ public void testMergeWithLimitMultiField() {
             createTextKeywordMultiField("text", "keyword2")
         ).build(MapperBuilderContext.root(false, false));
 
-        assertEquals(2, mergeInto.mapperSize());
-        assertEquals(2, mergeWith.mapperSize());
+        assertEquals(2, mergeInto.getTotalFieldsCount());
+        assertEquals(2, mergeWith.getTotalFieldsCount());
 
         ObjectMapper mergedAdd0 = mergeInto.merge(mergeWith, MapperMergeContext.root(false, false, 0));
         ObjectMapper mergedAdd1 = mergeInto.merge(mergeWith, MapperMergeContext.root(false, false, 1));
-        assertEquals(2, mergedAdd0.mapperSize());
-        assertEquals(3, mergedAdd1.mapperSize());
+        assertEquals(2, mergedAdd0.getTotalFieldsCount());
+        assertEquals(3, mergedAdd1.getTotalFieldsCount());
     }
 
     public void testMergeWithLimitRuntimeField() {
@@ -302,13 +302,13 @@ public void testMergeWithLimitRuntimeField() {
             new TestRuntimeField("existing_runtime_field", "keyword")
         ).addRuntimeField(new TestRuntimeField("new_runtime_field", "keyword")).build(MapperBuilderContext.root(false, false));
 
-        assertEquals(3, mergeInto.mapperSize());
-        assertEquals(2, mergeWith.mapperSize());
+        assertEquals(3, mergeInto.getTotalFieldsCount());
+        assertEquals(2, mergeWith.getTotalFieldsCount());
 
         ObjectMapper mergedAdd0 = mergeInto.merge(mergeWith, MapperMergeContext.root(false, false, 0));
         ObjectMapper mergedAdd1 = mergeInto.merge(mergeWith, MapperMergeContext.root(false, false, 1));
-        assertEquals(3, mergedAdd0.mapperSize());
-        assertEquals(4, mergedAdd1.mapperSize());
+        assertEquals(3, mergedAdd0.getTotalFieldsCount());
+        assertEquals(4, mergedAdd1.getTotalFieldsCount());
     }
 
     private static RootObjectMapper createRootSubobjectFalseLeafWithDots() {

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

@@ -530,15 +530,20 @@ public void testSyntheticSourceDocValuesFieldWithout() throws IOException {
         assertThat(mapper.mapping().getRoot().syntheticFieldLoader().docValuesLoader(null, null), nullValue());
     }
 
-    public void testNestedObjectWithMultiFieldsMapperSize() throws IOException {
+    public void testNestedObjectWithMultiFieldsgetTotalFieldsCount() {
         ObjectMapper.Builder mapperBuilder = new ObjectMapper.Builder("parent_size_1", Explicit.IMPLICIT_TRUE).add(
             new ObjectMapper.Builder("child_size_2", Explicit.IMPLICIT_TRUE).add(
                 new TextFieldMapper.Builder("grand_child_size_3", createDefaultIndexAnalyzers()).addMultiField(
                     new KeywordFieldMapper.Builder("multi_field_size_4", IndexVersion.current())
-                ).addMultiField(new KeywordFieldMapper.Builder("multi_field_size_5", IndexVersion.current()))
+                )
+                    .addMultiField(
+                        new TextFieldMapper.Builder("grand_child_size_5", createDefaultIndexAnalyzers()).addMultiField(
+                            new KeywordFieldMapper.Builder("multi_field_of_multi_field_size_6", IndexVersion.current())
+                        )
+                    )
             )
         );
-        assertThat(mapperBuilder.build(MapperBuilderContext.root(false, false)).mapperSize(), equalTo(5));
+        assertThat(mapperBuilder.build(MapperBuilderContext.root(false, false)).getTotalFieldsCount(), equalTo(6));
     }
 
     public void testWithoutMappers() throws IOException {

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

@@ -162,7 +162,7 @@ public void testRuntimeSection() throws IOException {
         }));
         MapperService mapperService = createMapperService(mapping);
         assertEquals(mapping, mapperService.documentMapper().mappingSource().toString());
-        assertEquals(3, mapperService.documentMapper().mapping().getRoot().mapperSize());
+        assertEquals(3, mapperService.documentMapper().mapping().getRoot().getTotalFieldsCount());
     }
 
     public void testRuntimeSectionRejectedUpdate() throws IOException {

test/framework/src/main/java/org/elasticsearch/index/mapper/MapperTestCase.java

@@ -427,6 +427,11 @@ public final void testMinimalToMaximal() throws IOException {
         assertParseMaximalWarnings();
     }
 
+    public void testTotalFieldsCount() throws IOException {
+        MapperService mapperService = createMapperService(fieldMapping(this::minimalMapping));
+        assertEquals(1, mapperService.documentMapper().mapping().getRoot().getTotalFieldsCount());
+    }
+
     protected final void assertParseMinimalWarnings() {
         String[] warnings = getParseMinimalWarnings();
         if (warnings.length > 0) {