Only allow one type on 7.0 indices (#24317)

This adds the `index.mapping.single_type` setting, which enforces that indices
have at most one type when it is true. The default value is true for 6.0+ indices
and false for old indices.

Relates #15613

core/src/main/java/org/elasticsearch/common/settings/IndexScopedSettings.java

@@ -135,6 +135,7 @@ public final class IndexScopedSettings extends AbstractScopedSettings {
         MapperService.INDEX_MAPPING_NESTED_FIELDS_LIMIT_SETTING,
         MapperService.INDEX_MAPPING_TOTAL_FIELDS_LIMIT_SETTING,
         MapperService.INDEX_MAPPING_DEPTH_LIMIT_SETTING,
+        MapperService.INDEX_MAPPING_SINGLE_TYPE_SETTING,
         BitsetFilterCache.INDEX_LOAD_RANDOM_ACCESS_FILTERS_EAGERLY_SETTING,
         IndexModule.INDEX_STORE_TYPE_SETTING,
         IndexModule.INDEX_STORE_PRE_LOAD_SETTING,

core/src/main/java/org/elasticsearch/index/mapper/MapperService.java

@@ -25,13 +25,15 @@
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.DelegatingAnalyzerWrapper;
 import org.elasticsearch.ElasticsearchGenerationException;
+import org.elasticsearch.Version;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.cluster.metadata.MappingMetaData;
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.compress.CompressedXContent;
 import org.elasticsearch.common.regex.Regex;
 import org.elasticsearch.common.settings.Setting;
 import org.elasticsearch.common.settings.Setting.Property;
+import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.NamedXContentRegistry;
 import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentParser;
@@ -94,6 +96,19 @@ public enum MergeReason {
     public static final boolean INDEX_MAPPER_DYNAMIC_DEFAULT = true;
     public static final Setting<Boolean> INDEX_MAPPER_DYNAMIC_SETTING =
         Setting.boolSetting("index.mapper.dynamic", INDEX_MAPPER_DYNAMIC_DEFAULT, Property.Dynamic, Property.IndexScope);
+    public static final Setting<Boolean> INDEX_MAPPING_SINGLE_TYPE_SETTING;
+    static {
+        Function<Settings, String> defValue = settings -> {
+            // TODO: uncomment this
+            /*boolean singleType = true;
+            if (settings.getAsVersion(IndexMetaData.SETTING_VERSION_CREATED, null) != null) {
+                singleType = Version.indexCreated(settings).onOrAfter(Version.V_6_0_0_alpha1_UNRELEASED);
+            }*/
+            boolean singleType = false;
+            return Boolean.valueOf(singleType).toString();
+        };
+        INDEX_MAPPING_SINGLE_TYPE_SETTING = Setting.boolSetting("index.mapping.single_type", defValue, Property.IndexScope, Property.Final);
+    }
     private static ObjectHashSet<String> META_FIELDS = ObjectHashSet.from(
             "_uid", "_id", "_type", "_all", "_parent", "_routing", "_index",
             "_size", "_timestamp", "_ttl"
@@ -457,6 +472,15 @@ private synchronized Map<String, DocumentMapper> internalMerge(@Nullable Documen
             }
         }
 
+        if (indexSettings.getValue(INDEX_MAPPING_SINGLE_TYPE_SETTING)) {
+            Set<String> actualTypes = new HashSet<>(mappers.keySet());
+            actualTypes.remove(DEFAULT_MAPPING);
+            if (actualTypes.size() > 1) {
+                throw new IllegalArgumentException(
+                        "Rejecting mapping update to [" + index().getName() + "] as the final mapping would have more than 1 type: " + actualTypes);
+            }
+        }
+
         // make structures immutable
         mappers = Collections.unmodifiableMap(mappers);
         results = Collections.unmodifiableMap(results);

core/src/test/java/org/elasticsearch/action/admin/indices/create/ShrinkIndexIT.java

@@ -143,7 +143,7 @@ public void testCreateShrinkIndex() {
             .put("index.version.created", version)
         ).get();
         for (int i = 0; i < 20; i++) {
-            client().prepareIndex("source", randomFrom("t1", "t2", "t3"))
+            client().prepareIndex("source", "type")
                 .setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", XContentType.JSON).get();
         }
         ImmutableOpenMap<String, DiscoveryNode> dataNodes = client().admin().cluster().prepareState().get().getState().nodes()
@@ -179,7 +179,7 @@ public void testCreateShrinkIndex() {
         }
 
         for (int i = 20; i < 40; i++) {
-            client().prepareIndex("target", randomFrom("t1", "t2", "t3"))
+            client().prepareIndex("target", "type")
                 .setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", XContentType.JSON).get();
         }
         flushAndRefresh();
@@ -197,7 +197,7 @@ public void testCreateShrinkIndexFails() throws Exception {
             .put("number_of_shards", randomIntBetween(2, 7))
             .put("number_of_replicas", 0)).get();
         for (int i = 0; i < 20; i++) {
-            client().prepareIndex("source", randomFrom("t1", "t2", "t3"))
+            client().prepareIndex("source", "type")
                 .setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", XContentType.JSON).get();
         }
         ImmutableOpenMap<String, DiscoveryNode> dataNodes = client().admin().cluster().prepareState().get().getState().nodes()
@@ -275,10 +275,10 @@ public void testCreateShrinkWithIndexSort() throws Exception {
                     .put("number_of_shards", 8)
                     .put("number_of_replicas", 0)
             )
-            .addMapping("t1", "id", "type=keyword,doc_values=true")
+            .addMapping("type", "id", "type=keyword,doc_values=true")
             .get();
         for (int i = 0; i < 20; i++) {
-            client().prepareIndex("source", "t1", Integer.toString(i))
+            client().prepareIndex("source", "type", Integer.toString(i))
                 .setSource("{\"foo\" : \"bar\", \"id\" : " + i + "}", XContentType.JSON).get();
         }
         ImmutableOpenMap<String, DiscoveryNode> dataNodes = client().admin().cluster().prepareState().get().getState().nodes()
@@ -326,7 +326,7 @@ public void testCreateShrinkWithIndexSort() throws Exception {
 
         // ... and that the index sort is also applied to updates
         for (int i = 20; i < 40; i++) {
-            client().prepareIndex("target", randomFrom("t1", "t2", "t3"))
+            client().prepareIndex("target", "type")
                 .setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", XContentType.JSON).get();
         }
         flushAndRefresh();

core/src/test/java/org/elasticsearch/action/bulk/BulkWithUpdatesIT.java

@@ -455,6 +455,7 @@ public void testBulkIndexingWhileInitializing() throws Exception {
      */
     public void testBulkUpdateDocAsUpsertWithParent() throws Exception {
         client().admin().indices().prepareCreate("test")
+                .setSettings("index.mapping.single_type", false)
                 .addMapping("parent", "{\"parent\":{}}", XContentType.JSON)
                 .addMapping("child", "{\"child\": {\"_parent\": {\"type\": \"parent\"}}}", XContentType.JSON)
                 .execute().actionGet();
@@ -519,6 +520,7 @@ public void testBulkUpdateDocAsUpsertWithParent() throws Exception {
      */
     public void testBulkUpdateUpsertWithParent() throws Exception {
         assertAcked(prepareCreate("test")
+                .setSettings("index.mapping.single_type", false)
                 .addMapping("parent", "{\"parent\":{}}", XContentType.JSON)
                 .addMapping("child", "{\"child\": {\"_parent\": {\"type\": \"parent\"}}}", XContentType.JSON));
         ensureGreen();
@@ -603,8 +605,10 @@ public void testBulkUpdateUpsertWithParent() throws Exception {
      * Test for https://github.com/elastic/elasticsearch/issues/8365
      */
     public void testBulkUpdateChildMissingParentRouting() throws Exception {
-        assertAcked(prepareCreate("test").addMapping("parent", "{\"parent\":{}}", XContentType.JSON)
-            .addMapping("child", "{\"child\": {\"_parent\": {\"type\": \"parent\"}}}", XContentType.JSON));
+        assertAcked(prepareCreate("test")
+                .setSettings("index.mapping.single_type", false)
+                .addMapping("parent", "{\"parent\":{}}", XContentType.JSON)
+                .addMapping("child", "{\"child\": {\"_parent\": {\"type\": \"parent\"}}}", XContentType.JSON));
         ensureGreen();
 
         BulkRequestBuilder builder = client().prepareBulk();

core/src/test/java/org/elasticsearch/aliases/IndexAliasesIT.java

@@ -826,6 +826,7 @@ public void testAliasFilterWithNowInRangeFilterAndQuery() throws Exception {
 
     public void testAliasesFilterWithHasChildQuery() throws Exception {
         assertAcked(prepareCreate("my-index")
+                        .setSettings("index.mapping.single_type", false)
                         .addMapping("parent")
                         .addMapping("child", "_parent", "type=parent")
         );

core/src/test/java/org/elasticsearch/cluster/metadata/MetaDataMappingServiceTests.java

@@ -54,6 +54,7 @@ public void testAddChildTypePointingToAlreadyExistingType() throws Exception {
     // Tests _parent meta field logic, because part of the validation is in MetaDataMappingService
     public void testAddExtraChildTypePointingToAlreadyParentExistingType() throws Exception {
         IndexService indexService = createIndex("test", client().admin().indices().prepareCreate("test")
+                .setSettings("index.mapping.single_type", false)
                 .addMapping("parent")
                 .addMapping("child1", "_parent", "type=parent")
         );

core/src/test/java/org/elasticsearch/fieldstats/FieldStatsTests.java

@@ -319,9 +319,9 @@ public void testMerge_notAvailable() {
 
     public void testNumberFiltering() {
         createIndex("test1", Settings.EMPTY, "type", "value", "type=long");
-        client().prepareIndex("test1", "test").setSource("value", 1L).get();
+        client().prepareIndex("test1", "type").setSource("value", 1L).get();
         createIndex("test2", Settings.EMPTY, "type", "value", "type=long");
-        client().prepareIndex("test2", "test").setSource("value", 3L).get();
+        client().prepareIndex("test2", "type").setSource("value", 3L).get();
         client().admin().indices().prepareRefresh().get();
 
         FieldStatsResponse response = client().prepareFieldStats()
@@ -426,10 +426,10 @@ public void testDateFiltering() {
         String dateTime2Str = DateFieldMapper.DEFAULT_DATE_TIME_FORMATTER.parser().print(dateTime2);
 
         createIndex("test1", Settings.EMPTY, "type", "value", "type=date", "value2", "type=date,index=false");
-        client().prepareIndex("test1", "test")
+        client().prepareIndex("test1", "type")
             .setSource("value", dateTime1Str, "value2", dateTime1Str).get();
         createIndex("test2", Settings.EMPTY, "type", "value", "type=date");
-        client().prepareIndex("test2", "test").setSource("value", dateTime2Str).get();
+        client().prepareIndex("test2", "type").setSource("value", dateTime2Str).get();
         client().admin().indices().prepareRefresh().get();
 
         FieldStatsResponse response = client().prepareFieldStats()

core/src/test/java/org/elasticsearch/gateway/RecoveryFromGatewayIT.java

@@ -318,6 +318,7 @@ public void testLatestVersionLoaded() throws Exception {
         // clean two nodes
         internalCluster().startNodes(2, Settings.builder().put("gateway.recover_after_nodes", 2).build());
 
+        assertAcked(client().admin().indices().prepareCreate("test").setSettings("index.mapping.single_type", false));
         client().prepareIndex("test", "type1", "1").setSource(jsonBuilder().startObject().field("field", "value1").endObject()).execute().actionGet();
         client().admin().indices().prepareFlush().execute().actionGet();
         client().prepareIndex("test", "type1", "2").setSource(jsonBuilder().startObject().field("field", "value2").endObject()).execute().actionGet();

core/src/test/java/org/elasticsearch/get/GetActionIT.java

@@ -35,7 +35,6 @@
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.lucene.uid.Versions;
 import org.elasticsearch.common.settings.Settings;
-import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.engine.VersionConflictEngineException;
@@ -255,7 +254,7 @@ public void testGetDocWithMultivaluedFields() throws Exception {
         assertAcked(prepareCreate("test")
                 .addMapping("type1", mapping1, XContentType.JSON)
                 .addMapping("type2", mapping2, XContentType.JSON)
-                .setSettings(Settings.builder().put("index.refresh_interval", -1)));
+                .setSettings("index.refresh_interval", -1, "index.mapping.single_type", false));
         ensureGreen();
 
         GetResponse response = client().prepareGet("test", "type1", "1").get();
@@ -530,7 +529,7 @@ public void testGetFieldsMetaData() throws Exception {
                 .addMapping("parent")
                 .addMapping("my-type1", "_parent", "type=parent", "field1", "type=keyword,store=true")
                 .addAlias(new Alias("alias"))
-                .setSettings(Settings.builder().put("index.refresh_interval", -1)));
+                .setSettings("index.refresh_interval", -1, "index.mapping.single_type", false));
 
         client().prepareIndex("test", "my-type1", "1")
                 .setRouting("1")
@@ -594,7 +593,7 @@ public void testGetFieldsNonLeafField() throws Exception {
 
     public void testGetFieldsComplexField() throws Exception {
         assertAcked(prepareCreate("my-index")
-                .setSettings(Settings.builder().put("index.refresh_interval", -1))
+                .setSettings("index.refresh_interval", -1, "index.mapping.single_type", false)
                 .addMapping("my-type2", jsonBuilder().startObject().startObject("my-type2").startObject("properties")
                         .startObject("field1").field("type", "object").startObject("properties")
                         .startObject("field2").field("type", "object").startObject("properties")
@@ -726,6 +725,7 @@ public void testUngeneratedFieldsThatAreAlwaysStored() throws IOException {
         String createIndexSource = "{\n" +
                 "  \"settings\": {\n" +
                 "    \"index.translog.flush_threshold_size\": \"1pb\",\n" +
+                "    \"index.mapping.single_type\": false," +
                 "    \"refresh_interval\": \"-1\"\n" +
                 "  },\n" +
                 "  \"mappings\": {\n" +
@@ -738,7 +738,8 @@ public void testUngeneratedFieldsThatAreAlwaysStored() throws IOException {
                 "    }\n" +
                 "  }\n" +
                 "}";
-        assertAcked(prepareCreate("test").addAlias(new Alias("alias")).setSource(createIndexSource, XContentType.JSON));
+        assertAcked(prepareCreate("test")
+                .addAlias(new Alias("alias")).setSource(createIndexSource, XContentType.JSON));
         ensureGreen();
 
         client().prepareIndex("test", "doc").setId("1").setSource("{}", XContentType.JSON).setParent("1").get();

core/src/test/java/org/elasticsearch/index/fielddata/AbstractFieldDataTestCase.java

@@ -31,7 +31,9 @@
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.RAMDirectory;
+import org.elasticsearch.common.compress.CompressedXContent;
 import org.elasticsearch.common.lucene.index.ElasticsearchDirectoryReader;
+import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.index.IndexService;
 import org.elasticsearch.index.cache.bitset.BitsetFilterCache;
 import org.elasticsearch.index.fielddata.IndexFieldData.XFieldComparatorSource.Nested;
@@ -41,6 +43,7 @@
 import org.elasticsearch.index.mapper.KeywordFieldMapper;
 import org.elasticsearch.index.mapper.MappedFieldType;
 import org.elasticsearch.index.mapper.Mapper.BuilderContext;
+import org.elasticsearch.index.mapper.MapperService.MergeReason;
 import org.elasticsearch.index.mapper.MapperService;
 import org.elasticsearch.index.mapper.NumberFieldMapper;
 import org.elasticsearch.index.mapper.ParentFieldMapper;
@@ -131,7 +134,7 @@ public <IFD extends IndexFieldData<?>> IFD getForField(String type, String field
 
     @Before
     public void setup() throws Exception {
-        indexService = createIndex("test");
+        indexService = createIndex("test", Settings.builder().put("mapping.single_type", false).build());
         mapperService = indexService.mapperService();
         indicesFieldDataCache = getInstanceFromNode(IndicesService.class).getIndicesFieldDataCache();
         ifdService = indexService.fieldData();

core/src/test/java/org/elasticsearch/index/mapper/DynamicMappingIT.java

@@ -71,7 +71,7 @@ private static void assertMappingsHaveField(GetMappingsResponse mappings, String
     }
 
     public void testMappingsPropagatedToMasterNodeImmediately() throws IOException {
-        createIndex("index");
+        assertAcked(prepareCreate("index").setSettings("index.mapping.single_type", false));
 
         // works when the type has been dynamically created
         client().prepareIndex("index", "type", "1").setSource("foo", 3).get();

core/src/test/java/org/elasticsearch/index/mapper/DynamicMappingTests.java

@@ -34,6 +34,7 @@
 import org.elasticsearch.index.IndexService;
 import org.elasticsearch.index.mapper.BooleanFieldMapper.BooleanFieldType;
 import org.elasticsearch.index.mapper.DateFieldMapper.DateFieldType;
+import org.elasticsearch.index.mapper.MapperService.MergeReason;
 import org.elasticsearch.index.mapper.NumberFieldMapper.NumberFieldType;
 import org.elasticsearch.test.ESSingleNodeTestCase;
 
@@ -524,7 +525,7 @@ public void testReuseExistingMappings() throws IOException, Exception {
     }
 
     public void testMixTemplateMultiFieldAndMappingReuse() throws Exception {
-        IndexService indexService = createIndex("test");
+        IndexService indexService = createIndex("test", Settings.builder().put("mapping.single_type", false).build());
         XContentBuilder mappings1 = jsonBuilder().startObject()
                 .startObject("type1")
                     .startArray("dynamic_templates")

core/src/test/java/org/elasticsearch/index/mapper/MapperServiceTests.java

@@ -20,7 +20,6 @@
 package org.elasticsearch.index.mapper;
 
 import org.elasticsearch.ExceptionsHelper;
-import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.compress.CompressedXContent;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContentFactory;
@@ -30,6 +29,7 @@
 import org.elasticsearch.index.mapper.MapperService.MergeReason;
 import org.elasticsearch.index.mapper.NumberFieldMapper.NumberFieldType;
 import org.elasticsearch.test.ESSingleNodeTestCase;
+import org.hamcrest.Matchers;
 
 import java.io.IOException;
 import java.io.UncheckedIOException;
@@ -74,7 +74,7 @@ public void testTypeNameTooLong() {
     }
 
     public void testTypes() throws Exception {
-        IndexService indexService1 = createIndex("index1");
+        IndexService indexService1 = createIndex("index1", Settings.builder().put("index.mapping.single_type", false).build());
         MapperService mapperService = indexService1.mapperService();
         assertEquals(Collections.emptySet(), mapperService.types());
 
@@ -207,7 +207,7 @@ public void testMergeParentTypesSame() {
     }
 
     public void testOtherDocumentMappersOnlyUpdatedWhenChangingFieldType() throws IOException {
-        IndexService indexService = createIndex("test");
+        IndexService indexService = createIndex("test", Settings.builder().put("index.mapping.single_type", false).build());
 
         CompressedXContent simpleMapping = new CompressedXContent(XContentFactory.jsonBuilder().startObject()
             .startObject("properties")
@@ -309,4 +309,16 @@ public void testIndexSortWithNestedFields() throws IOException {
         assertThat(invalidNestedException.getMessage(),
             containsString("cannot have nested fields when index sort is activated"));
     }
+
+    @AwaitsFix(bugUrl="https://github.com/elastic/elasticsearch/pull/24317#issuecomment-297624290")
+    public void testForbidMultipleTypes() throws IOException {
+        String mapping = XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject().string();
+        MapperService mapperService = createIndex("test").mapperService();
+        mapperService.merge("type", new CompressedXContent(mapping), MergeReason.MAPPING_UPDATE, randomBoolean());
+
+        String mapping2 = XContentFactory.jsonBuilder().startObject().startObject("type2").endObject().endObject().string();
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class,
+                () -> mapperService.merge("type2", new CompressedXContent(mapping2), MergeReason.MAPPING_UPDATE, randomBoolean()));
+        assertThat(e.getMessage(), Matchers.startsWith("Rejecting mapping update to [test] as the final mapping would have more than 1 type: "));
+    }
 }