elasticsearch索引index之put mapping怎么设置

本篇内容主要讲解“elasticsearch索引index之put mapping怎么设置”，感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷，实用性强。下面就让小编来带大家学习“elasticsearch索引index之put mapping怎么设置”吧!

mapping机制使得elasticsearch索引数据变的更加灵活，近乎于no schema。mapping可以在建立索引时设置，也可以在后期设置。后期设置可以是修改mapping（无法对已有的field属性进行修改，一般来说只是增加新的field）或者对没有mapping的索引设置mapping。put mapping操作必须是master节点来完成，因为它涉及到集群matedata的修改，同时它跟index和type密切相关。修改只是针对特定index的特定type。

在Action support分析中我们分析过几种Action的抽象类型，put mapping Action属于TransportMasterNodeOperationAction的子类。它实现了masterOperation方法，每个继承自TransportMasterNodeOperationAction的子类都会根据自己的具体功能来实现这个方法。这里的实现如下所示：

protected void masterOperation(final PutMappingRequest request, final ClusterState state, final ActionListener<PutMappingResponse> listener) throws ElasticsearchException {         final String[] concreteIndices = clusterService.state().metaData().concreteIndices(request.indicesOptions(), request.indices()); 　　　　　　//构造request         PutMappingClusterStateUpdateRequest updateRequest = new PutMappingClusterStateUpdateRequest()                 .ackTimeout(request.timeout()).masterNodeTimeout(request.masterNodeTimeout())                 .indices(concreteIndices).type(request.type())                 .source(request.source()).ignoreConflicts(request.ignoreConflicts()); 　　　　　　//调用putMapping方法，同时传入一个Listener         metaDataMappingService.putMapping(updateRequest, new ActionListener<ClusterStateUpdateResponse>() {             @Override             public void onResponse(ClusterStateUpdateResponse response) {                 listener.onResponse(new PutMappingResponse(response.isAcknowledged()));             }             @Override             public void onFailure(Throwable t) {                 logger.debug("failed to put mappings on indices [{}], type [{}]", t, concreteIndices, request.type());                 listener.onFailure(t);             }         });     }

以上是TransportPutMappingAction对masterOperation方法的实现，这里并没有多少复杂的逻辑和操作。具体操作在matedataMappingService中。跟之前的CreateIndex一样，put Mapping也是向master提交一个updateTask。所有逻辑也都在execute方法中。这个task的基本跟CreateIndex一样，也需要在给定的时间内响应。它的代码如下所示：

public void putMapping(final PutMappingClusterStateUpdateRequest request, final ActionListener<ClusterStateUpdateResponse> listener) { 　　　　//提交一个高基本的updateTask         clusterService.submitStateUpdateTask("put-mapping [" + request.type() + "]", Priority.HIGH, new AckedClusterStateUpdateTask<ClusterStateUpdateResponse>(request, listener) {             @Override             protected ClusterStateUpdateResponse newResponse(boolean acknowledged) {                 return new ClusterStateUpdateResponse(acknowledged);             }             @Override             public ClusterState execute(final ClusterState currentState) throws Exception {                 List<String> indicesToClose = Lists.newArrayList();                 try { 　　　　　　　　　　　　//必须针对已经在matadata中存在的index，否则抛出异常                     for (String index : request.indices()) {                         if (!currentState.metaData().hasIndex(index)) {                             throw new IndexMissingException(new Index(index));                         }                     }                     //还需要存在于indices中，否则无法进行操作。所以这里要进行预建                     for (String index : request.indices()) {                         if (indicesService.hasIndex(index)) {                             continue;                         }                         final IndexMetaData indexMetaData = currentState.metaData().index(index); 　　　　　　　　　　　　　　//不存在就进行创建                         IndexService indexService = indicesService.createIndex(indexMetaData.index(), indexMetaData.settings(), clusterService.localNode().id());                         indicesToClose.add(indexMetaData.index());                         // make sure to add custom default mapping if exists                         if (indexMetaData.mappings().containsKey(MapperService.DEFAULT_MAPPING)) {                             indexService.mapperService().merge(MapperService.DEFAULT_MAPPING, indexMetaData.mappings().get(MapperService.DEFAULT_MAPPING).source(), false);                         }                         // only add the current relevant mapping (if exists)                         if (indexMetaData.mappings().containsKey(request.type())) {                             indexService.mapperService().merge(request.type(), indexMetaData.mappings().get(request.type()).source(), false);                         }                     } 　　　　　　　　　　　　//合并更新Mapping                     Map<String, DocumentMapper> newMappers = newHashMap();                     Map<String, DocumentMapper> existingMappers = newHashMap(); 　　　　　　　　　　　　//针对每个index进行Mapping合并                     for (String index : request.indices()) {                         IndexService indexService = indicesService.indexServiceSafe(index);                         // try and parse it (no need to add it here) so we can bail early in case of parsing exception                         DocumentMapper newMapper;                         DocumentMapper existingMapper = indexService.mapperService().documentMapper(request.type());                         if (MapperService.DEFAULT_MAPPING.equals(request.type())) {//存在defaultmapping则合并default mapping                             // _default_ types do not go through merging, but we do test the new settings. Also don't apply the old default                             newMapper = indexService.mapperService().parse(request.type(), new CompressedString(request.source()), false);                         } else {                             newMapper = indexService.mapperService().parse(request.type(), new CompressedString(request.source()), existingMapper == null);                             if (existingMapper != null) {                                 // first, simulate                                 DocumentMapper.MergeResult mergeResult = existingMapper.merge(newMapper, mergeFlags().simulate(true));                                 // if we have conflicts, and we are not supposed to ignore them, throw an exception                                 if (!request.ignoreConflicts() && mergeResult.hasConflicts()) {                                     throw new MergeMappingException(mergeResult.conflicts());                                 }                             }                         }                         newMappers.put(index, newMapper);                         if (existingMapper != null) {                             existingMappers.put(index, existingMapper);                         }                     }                     String mappingType = request.type();                     if (mappingType == null) {                         mappingType = newMappers.values().iterator().next().type();                     } else if (!mappingType.equals(newMappers.values().iterator().next().type())) {                         throw new InvalidTypeNameException("Type name provided does not match type name within mapping definition");                     }                     if (!MapperService.DEFAULT_MAPPING.equals(mappingType) && !PercolatorService.TYPE_NAME.equals(mappingType) && mappingType.charAt(0) == '_') {                         throw new InvalidTypeNameException("Document mapping type name can't start with '_'");                     }                     final Map<String, MappingMetaData> mappings = newHashMap();                     for (Map.Entry<String, DocumentMapper> entry : newMappers.entrySet()) {                         String index = entry.getKey();                         // do the actual merge here on the master, and update the mapping source                         DocumentMapper newMapper = entry.getValue();                         IndexService indexService = indicesService.indexService(index);                         if (indexService == null) {                             continue;                         }                         CompressedString existingSource = null;                         if (existingMappers.containsKey(entry.getKey())) {                             existingSource = existingMappers.get(entry.getKey()).mappingSource();                         }                         DocumentMapper mergedMapper = indexService.mapperService().merge(newMapper.type(), newMapper.mappingSource(), false);                         CompressedString updatedSource = mergedMapper.mappingSource();                         if (existingSource != null) {                             if (existingSource.equals(updatedSource)) {                                 // same source, no changes, ignore it                             } else {                                 // use the merged mapping source                                 mappings.put(index, new MappingMetaData(mergedMapper));                                 if (logger.isDebugEnabled()) {                                     logger.debug("[{}] update_mapping [{}] with source [{}]", index, mergedMapper.type(), updatedSource);                                 } else if (logger.isInfoEnabled()) {                                     logger.info("[{}] update_mapping [{}]", index, mergedMapper.type());                                 }                             }                         } else {                             mappings.put(index, new MappingMetaData(mergedMapper));                             if (logger.isDebugEnabled()) {                                 logger.debug("[{}] create_mapping [{}] with source [{}]", index, newMapper.type(), updatedSource);                             } else if (logger.isInfoEnabled()) {                                 logger.info("[{}] create_mapping [{}]", index, newMapper.type());                             }                         }                     }                     if (mappings.isEmpty()) {                         // no changes, return                         return currentState;                     } 　　　　　　　　　　　　//根据mapping的更新情况重新生成matadata                     MetaData.Builder builder = MetaData.builder(currentState.metaData());                     for (String indexName : request.indices()) {                         IndexMetaData indexMetaData = currentState.metaData().index(indexName);                         if (indexMetaData == null) {                             throw new IndexMissingException(new Index(indexName));                         }                         MappingMetaData mappingMd = mappings.get(indexName);                         if (mappingMd != null) {                             builder.put(IndexMetaData.builder(indexMetaData).putMapping(mappingMd));                         }                     }                     return ClusterState.builder(currentState).metaData(builder).build();                 } finally {                     for (String index : indicesToClose) {                         indicesService.removeIndex(index, "created for mapping processing");                     }                 }             }         });     }

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