本文主要是介绍apache kylin的一些注意事项(解决kylin报错Storage schema reading not supported)，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
1.目前我所使用的kylin版本为2.6.2，有时在完成一次构建后会出现fail to locate kylin.properties的异常，如图所示
经排查，定位到kylin源码中的
org.apache.kylin.engine.mr.common.AbstractHadoopJob中的loadKylinPropsAndMetadata方法，如图所示
我发现在执行cube构建任务时拆分的job会频繁调用这个方法，但这里这么写有些看不懂，不知道是个BUG还是有其他原因，总之这里不正确的更新了kylin_conf环境变量的路径。这个问题我会在后续升级版本中持续关注，目前的解决方法是，在kylin根目录下创建名为meta的文件夹，并将conf目录下的所有配置文件拷贝进去或者创建一个软连接。
2.因为业务数据存储在hbase上，因此在使用kylin分析时，需要先将hbase的数据mapping到hive上，再在kylin中load hive table。但在kylin中load table报错，而且普通表load没问题，只有mapping hbase的表才会报错，报的异常为java.lang.UnsupportedOperationException: Storage schema reading not supported
track输出为
java.lang.RuntimeException: cannot get HiveTableMetaat org.apache.kylin.source.hive.HiveMetadataExplorer.loadTableMetadata(HiveMetadataExplorer.java:68)at org.apache.kylin.rest.service.TableService.extractHiveTableMeta(TableService.java:205)at org.apache.kylin.rest.service.TableService.loadHiveTablesToProject(TableService.java:131)at org.apache.kylin.rest.controller.TableController.loadHiveTables(TableController.java:113)at sun.reflect.GeneratedMethodAccessor191.invoke(Unknown Source)at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)at java.lang.reflect.Method.invoke(Method.java:497)at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205)at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133)at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:97)at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827)at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738)at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967)at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)at javax.servlet.http.HttpServlet.service(HttpServlet.java:661)at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:317)at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:127)at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:91)at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:114)at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:137)at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:111)at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:170)at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:63)at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilterInternal(BasicAuthenticationFilter.java:215)at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:200)at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:116)at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:64)at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:56)at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:105)at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:214)at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:177)at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:262)at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)at com.thetransactioncompany.cors.CORSFilter.doFilter(CORSFilter.java:209)at com.thetransactioncompany.cors.CORSFilter.doFilter(CORSFilter.java:244)at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:493)at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:650)at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:800)at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:806)at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1498)at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)at java.lang.Thread.run(Thread.java:745)
Caused by: MetaException(message:java.lang.UnsupportedOperationException: Storage schema reading not supported)at org.apache.hadoop.hive.metastore.HiveMetaStore$HMSHandler.newMetaException(HiveMetaStore.java:6935)at org.apache.hadoop.hive.metastore.HiveMetaStore$HMSHandler.get_fields_with_environment_context(HiveMetaStore.java:5182)at org.apache.hadoop.hive.metastore.HiveMetaStore$HMSHandler.get_fields(HiveMetaStore.java:5144)at sun.reflect.GeneratedMethodAccessor165.invoke(Unknown Source)at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)at java.lang.reflect.Method.invoke(Method.java:497)at org.apache.hadoop.hive.metastore.RetryingHMSHandler.invokeInternal(RetryingHMSHandler.java:147)at org.apache.hadoop.hive.metastore.RetryingHMSHandler.invoke(RetryingHMSHandler.java:108)at com.sun.proxy.$Proxy70.get_fields(Unknown Source)at org.apache.hadoop.hive.metastore.HiveMetaStoreClient.getFields(HiveMetaStoreClient.java:1845)at org.apache.hadoop.hive.metastore.HiveMetaStoreClient.getFields(HiveMetaStoreClient.java:1839)at org.apache.kylin.source.hive.CLIHiveClient.getHiveTableMeta(CLIHiveClient.java:78)at org.apache.kylin.source.hive.HiveMetadataExplorer.loadTableMetadata(HiveMetadataExplorer.java:66)... 80 more报错原因是kylin在load表的时候，需要调用StorageSchemaReader接口的readSchema方法，默认的default是没有这个实现方法的就会报错。
解决方法是配置hive-site.xml中的属性
<property>
<name>metastore.storage.schema.reader.impl</name>
<value>org.apache.hadoop.hive.metastore.SerDeStorageSchemaReader</value>
</property>
3.目前kylin的authorization（授权）部分采用kylin自带的权限机制，根据不同的角色来授予不同的权限。authentication（鉴权）部分采用ldap的账号体系来进行用户登陆认证（具体接入ldap的方法参见我的其他文章）。我的权限控制需求是，在ldap中控制具体的用户登陆名，密码等等，用户分为管理者和查询者且查询者只能查归属项目下指定的表（并非所有表都可查）。
具体实现策略如下：
（1）ldap: ou=kylin_user对应平台所有用户，uid为登录名，userPassword为密码（默认加密方式即可）。 ou=kylin_group对应平台角色，cn为角色名，member对应角色所分配的用户，目前所有角色分为admin角色和普通角色，即ou=kylin_group中的cn=admin表示admin角色，它对应的member用户即为admin用户，admin用户在kylin中具有所有操作的权限。其他未赋予角色的用户为普通角色。
（2）在ldap中创建好了对应的用户和用户组之后，需要在kylin中配置ldap相关参数，具体参考我的kylin接入ldap篇。接入完成后，再在7070/kylin中使用admin账号登陆，点击左上角的“management project”按钮，选择对应的project，然后在access选项卡中 配置普通用户的角色，如图所示
普通用户的角色有四种，分别是ADMIN,MANAGEMENT,OPERATOR,QUERY，admin是超管，默认不要赋给普通用户此权限。management是project的管理员，可以执行该project下的所有操作。operator是操作者，能执行该project下的model创建，cube创建构建，insight查询等等，但无法在management project中管理project。query是最低权限者，只能执行该project对应的insight查询，适用于普通的查询数据的用户。
（3）普通查询用户需要再额外配置表权限，使特定用户只能查特定表（默认是query权限的用户可以查询该project下的所有表）。具体配置方法是使用高级用户，在首页model下的datasource选项卡中，在左侧选择需要配置权限的表，然后在右侧的access选项卡中 增加grant，选择对应的用户。或者删除某个用户使其无法查询该表。如图所示
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