It seems that mysql have some problem, I find some related webpage provide follow method to resolve this error:
Add below content in /etc/mysql/my.cnf: wait_timeout=31536000 interactive_timeout=31536000 Then restart mysql. I’m not sure it works, you can try. > 在 2020年9月11日，17:37，hubert stefani <hubert_stef...@yahoo.fr.INVALID> 写道： > > we did so (we found out the jar was actually missing), and then we got the > error below. (additional information : we try to deploy on aws emr 5.30) > > com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link > failure > > The last packet sent successfully to the server was 0 milliseconds ago. The > driver has not received any packets from the server. > at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) > at > sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) > at > sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) > at java.lang.reflect.Constructor.newInstance(Constructor.java:423) > at com.mysql.jdbc.Util.handleNewInstance(Util.java:408) > at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1137) > at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:356) > at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2504) > > is there a step to create the database, create users and grant roles ? > Hubert > Le vendredi 11 septembre 2020 à 09:30:27 UTC, Yaqian Zhang > <yaqian_zh...@126.com> a écrit : > > Hi Hubert: > > Have you put mysql-connector-java-xxx.jar into $KYLIN_HOME/ext ? > > You can download the mysql JDBC jar from > https://downloads.mysql.com/archives/c-j/ > <https://downloads.mysql.com/archives/c-j/>. > >> 在 2020年9月11日，17:17，hubert stefani <hubert_stef...@yahoo.fr.INVALID> 写道： >> >> Hi, >> we encounter the following error when we start the Web UI. it seems that >> mysql-driver is missing. Have we made a misconfiguration ? Is there a >> detailed configuration ? >> >> >> Exception in thread "main" java.lang.IllegalArgumentException: Failed to >> find metadata store by url: >> kylin_metadata@jdbc,url=jdbc:mysql://localhost:3306/kylin,username=XXXX,password=XXXXXX,maxActive=10,maxIdle=10 >> at >> org.apache.kylin.common.persistence.ResourceStore.createResourceStore(ResourceStore.java:101) >> at >> org.apache.kylin.common.persistence.ResourceStore.getStore(ResourceStore.java:113) >> at >> org.apache.kylin.common.persistence.ResourceTool.copyParallel(ResourceTool.java:153) >> at >> org.apache.kylin.common.persistence.ResourceTool.main(ResourceTool.java:102) >> Caused by: java.lang.reflect.InvocationTargetException >> at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) >> at >> sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) >> at >> sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) >> at java.lang.reflect.Constructor.newInstance(Constructor.java:423) >> at >> org.apache.kylin.common.persistence.ResourceStore.createResourceStore(ResourceStore.java:94) >> ... 3 more >> Caused by: java.lang.IllegalArgumentException: >> org.apache.commons.dbcp.SQLNestedException: Cannot load JDBC driver class >> 'com.mysql.jdbc.Driver' >> at >> org.apache.kylin.common.persistence.JDBCConnectionManager.<init>(JDBCConnectionManager.java:68) >> at >> org.apache.kylin.common.persistence.JDBCConnectionManager.getConnectionManager(JDBCConnectionManager.java:48) >> >> Regards,Hubert
