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OpenKM 7.1
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MySQL 8 troubleshooting

 Could not create a connection to the database server

There might be several reasons why the application cannot establish the link to the database; look at the log file, which might give clues about what is happening.

Strong Password Encryption for Authentication

The latest MySQL installation wizard suggests you use "Strong Password Encryption for Authentication," as can be shown in the following screenshot:

When the option "Strong Password Encryption for Authentication" is enabled rather than "Legacy Authentication Method," you are enabling an SSL connection by default. That means you might read some literature and apply changes in your connection setting to your server.xml server to connect with the database. Usually, in this scenario, you will get some error like what is shown below:

java.sql.SQLException: Cannot create PoolableConnectionFactory (Could not create connection to database server. Attempted reconnect 3 times. Giving up.)
	at org.apache.tomcat.dbcp.dbcp2.BasicDataSource.createPoolableConnectionFactory(BasicDataSource.java:2303) ~[tomcat-dbcp.jar:8.5.14]
	at org.apache.tomcat.dbcp.dbcp2.BasicDataSource.createDataSource(BasicDataSource.java:2043) ~[tomcat-dbcp.jar:8.5.14]
	at org.apache.tomcat.dbcp.dbcp2.BasicDataSource.getConnection(BasicDataSource.java:1543) ~[tomcat-dbcp.jar:8.5.14]
	at org.hibernate.connection.DatasourceConnectionProvider.getConnection(DatasourceConnectionProvider.java:92) ~[hibernate-core-3.6.10.Final.jar:3.6.10.Final]
	at org.hibernate.cfg.SettingsFactory.buildSettings(SettingsFactory.java:113) ~[hibernate-core-3.6.10.Final.jar:3.6.10.Final]
	at org.hibernate.cfg.Configuration.buildSettingsInternal(Configuration.java:2863) [hibernate-core-3.6.10.Final.jar:3.6.10.Final]
	at org.hibernate.cfg.Configuration.buildSettings(Configuration.java:2859) [hibernate-core-3.6.10.Final.jar:3.6.10.Final]
	at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1870) [hibernate-core-3.6.10.Final.jar:3.6.10.Final]
	at com.openkm.dao.HibernateUtil.getSessionFactory(HibernateUtil.java:367) [classes/:6.4.43-DEV]
	at com.openkm.dao.HibernateUtil.getSessionFactory(HibernateUtil.java:182) [classes/:6.4.43-DEV]
	at com.openkm.servlet.RepositoryStartupServlet.init(RepositoryStartupServlet.java:99) [classes/:6.4.43-DEV]
	at javax.servlet.GenericServlet.init(GenericServlet.java:158) [servlet-api.jar:3.1.FR]
	at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1183) [catalina.jar:8.5.14]
	at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1099) [catalina.jar:8.5.14]
	at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:989) [catalina.jar:8.5.14]
	at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:4931) [catalina.jar:8.5.14]
	at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5241) [catalina.jar:8.5.14]
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) [catalina.jar:8.5.14]
	at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:752) [catalina.jar:8.5.14]
	at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:728) [catalina.jar:8.5.14]
	at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:734) [catalina.jar:8.5.14]
	at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:952) [catalina.jar:8.5.14]
	at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1823) [catalina.jar:8.5.14]
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [na:1.8.0_171]
	at java.util.concurrent.FutureTask.run(FutureTask.java:266) [na:1.8.0_171]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_171]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_171]
	at java.lang.Thread.run(Thread.java:748) [na:1.8.0_171]
Caused by: java.sql.SQLNonTransientConnectionException: Could not create connection to database server. Attempted reconnect 3 times. Giving up.
	at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:108) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:95) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:87) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:61) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:71) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at com.mysql.cj.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:932) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:857) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:444) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:230) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:226) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at org.apache.tomcat.dbcp.dbcp2.DriverConnectionFactory.createConnection(DriverConnectionFactory.java:38) ~[tomcat-dbcp.jar:8.5.14]
	at org.apache.tomcat.dbcp.dbcp2.PoolableConnectionFactory.makeObject(PoolableConnectionFactory.java:257) ~[tomcat-dbcp.jar:8.5.14]
	at org.apache.tomcat.dbcp.dbcp2.BasicDataSource.validateConnectionFactory(BasicDataSource.java:2313) ~[tomcat-dbcp.jar:8.5.14]
	at org.apache.tomcat.dbcp.dbcp2.BasicDataSource.createPoolableConnectionFactory(BasicDataSource.java:2299) ~[tomcat-dbcp.jar:8.5.14]
	... 27 common frames omitted
Caused by: com.mysql.cj.exceptions.CJCommunicationsException: 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) ~[na:1.8.0_171]
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_171]
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_171]
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_171]
	at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:59) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:103) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:149) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:165) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at com.mysql.cj.protocol.a.NativeProtocol.negotiateSSLConnection(NativeProtocol.java:355) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at com.mysql.cj.protocol.a.NativeAuthenticationProvider.negotiateSSLConnection(NativeAuthenticationProvider.java:789) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at com.mysql.cj.protocol.a.NativeAuthenticationProvider.proceedHandshakeWithPluggableAuthentication(NativeAuthenticationProvider.java:499) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at com.mysql.cj.protocol.a.NativeAuthenticationProvider.connect(NativeAuthenticationProvider.java:217) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at com.mysql.cj.protocol.a.NativeProtocol.connect(NativeProtocol.java:1411) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at com.mysql.cj.NativeSession.connect(NativeSession.java:165) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at com.mysql.cj.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:876) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	... 35 common frames omitted
Caused by: javax.net.ssl.SSLHandshakeException: java.security.cert.CertificateException: java.security.cert.CertPathValidatorException: Path does not chain with any of the trust anchors
	at sun.security.ssl.Alerts.getSSLException(Alerts.java:192) ~[na:1.8.0_171]
	at sun.security.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1964) ~[na:1.8.0_171]
	at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:328) ~[na:1.8.0_171]
	at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:322) ~[na:1.8.0_171]
	at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1614) ~[na:1.8.0_171]
	at sun.security.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:216) ~[na:1.8.0_171]
	at sun.security.ssl.Handshaker.processLoop(Handshaker.java:1052) ~[na:1.8.0_171]
	at sun.security.ssl.Handshaker.process_record(Handshaker.java:987) ~[na:1.8.0_171]
	at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:1072) ~[na:1.8.0_171]
	at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1385) ~[na:1.8.0_171]
	at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1413) ~[na:1.8.0_171]
	at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1397) ~[na:1.8.0_171]
	at com.mysql.cj.protocol.ExportControlled.performTlsHandshake(ExportControlled.java:213) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at com.mysql.cj.protocol.StandardSocketFactory.performTlsHandshake(StandardSocketFactory.java:206) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at com.mysql.cj.protocol.a.NativeSocketConnection.performTlsHandshake(NativeSocketConnection.java:99) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at com.mysql.cj.protocol.a.NativeProtocol.negotiateSSLConnection(NativeProtocol.java:350) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	... 41 common frames omitted
Caused by: java.security.cert.CertificateException: java.security.cert.CertPathValidatorException: Path does not chain with any of the trust anchors
	at com.mysql.cj.protocol.ExportControlled$X509TrustManagerWrapper.checkServerTrusted(ExportControlled.java:280) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at sun.security.ssl.AbstractTrustManagerWrapper.checkServerTrusted(SSLContextImpl.java:985) ~[na:1.8.0_171]
	at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1596) ~[na:1.8.0_171]
	... 52 common frames omitted
Caused by: java.security.cert.CertPathValidatorException: Path does not chain with any of the trust anchors
	at sun.security.provider.certpath.PKIXCertPathValidator.validate(PKIXCertPathValidator.java:154) ~[na:1.8.0_171]
	at sun.security.provider.certpath.PKIXCertPathValidator.engineValidate(PKIXCertPathValidator.java:80) ~[na:1.8.0_171]
	at java.security.cert.CertPathValidator.validate(CertPathValidator.java:292) ~[na:1.8.0_171]
	at com.mysql.cj.protocol.ExportControlled$X509TrustManagerWrapper.checkServerTrusted(ExportControlled.java:273) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	... 54 common frames omitted

You have two options:

  • Configure SSL for the MySQL connection.
  • Switch from "Strong Password Encryption for Authentication" to "Legacy Authentication Method."

Some URLs that might be helpful for you if you decide to go ahead with SSL configuration:

In Windows is relatively easy to enable the "Legacy Authentication Method":

  • Execute the installer.
  • Click on reconfigure beside MySQL Server.
  • Follow the wizard screens and choose "Legacy Authentication Method."

Old JDBC driver

If your log file is shown the error below:

Caused by: java.lang.NullPointerException: null
	at com.mysql.jdbc.ConnectionImpl.getServerCharset(ConnectionImpl.java:3005) ~[mysql-connector-java-5.1.38-bin.jar:5.1.38]
	at com.mysql.jdbc.MysqlIO.sendConnectionAttributes(MysqlIO.java:1916) ~[mysql-connector-java-5.1.38-bin.jar:5.1.38]
	at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1845) ~[mysql-connector-java-5.1.38-bin.jar:5.1.38]
	at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1215) ~[mysql-connector-java-5.1.38-bin.jar:5.1.38]
	at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2255) ~[mysql-connector-java-5.1.38-bin.jar:5.1.38]
	at com.mysql.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:2106) ~[mysql-connector-java-5.1.38-bin.jar:5.1.38]
	... 41 common frames omitted

You are using the wrong driver version for connecting to MySQL Server 8; you should make the following changes:

  • Replace the MySQL-connector-java-5.1.38-bin.jar into your $TOMCAT_HOME/libs with the latest JDBC driver for MySQL Server 8. You can get the newest driver from https://dev.mysql.com/downloads/connector/j/.
  • Change the MySQL connection settings set into your $TOMCAT_HOME/conf/server.xml; it should be something like this:

In the latest version of MySQL JDBC driver, the name of the class com.MySQL.jdbc.The driver has been changed to com.MySQL.cj.JDBC.Driver.

<Resource name="jdbc/OpenKMDS" auth="Container" type="javax.sql.DataSource"
            maxTotal="100" maxIdle="30" maxWaitMillis="10000" validationQuery="select 1"
            username="openkm" password="openkm" driverClassName="com.mysql.cj.jdbc.Driver"
            url="jdbc:mysql://localhost:3306/okmdb?autoReconnect=true&amp;useUnicode=true&amp;characterEncoding=UTF8>

The server time zone value is unrecognized. 

If your log file is shown the error below or similar:

Caused by: com.mysql.cj.exceptions.InvalidConnectionAttributeException: The server time zone value 'CEST' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the serverTimezone configuration property) to use a more specifc time zone value if you want to utilize time zone support.
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_171]
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_171]
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_171]
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_171]
	at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:59) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:83) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at com.mysql.cj.util.TimeUtil.getCanonicalTimezone(TimeUtil.java:128) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at com.mysql.cj.protocol.a.NativeProtocol.configureTimezone(NativeProtocol.java:2201) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at com.mysql.cj.protocol.a.NativeProtocol.initServerSession(NativeProtocol.java:2225) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at com.mysql.cj.jdbc.ConnectionImpl.initializePropsFromServer(ConnectionImpl.java:1391) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	at com.mysql.cj.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:895) ~[mysql-connector-java-8.0.11.jar:8.0.11]
	... 45 common frames omitted

It seems the latest MySQL JDBC driver have some issue with your OS time zone configuration; a quick workaround is to indicate the server time zone, for example, serverTimezone=UTC:

<Resource name="jdbc/OpenKMDS" auth="Container" type="javax.sql.DataSource"
            maxTotal="100" maxIdle="30" maxWaitMillis="10000" validationQuery="select 1"
            username="openkm" password="openkm" driverClassName="com.mysql.cj.jdbc.Driver"
            url="jdbc:mysql://localhost:3306/okmdb_test?autoReconnect=true&amp;useUnicode=true&amp;characterEncoding=UTF8&amp;serverTimezone=UTC"/>

Problem connecting to your database

If you get an error like this:

Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Public Key Retrieval is not allowed

You need to modify your file conf/server.xml and add the following to the URL by JDBC: allowPublicKeyRetrieval=true.

<Resource name="jdbc/OpenKMDS" auth="Container" type="javax.sql.DataSource"
            maxTotal="100" maxIdle="30" maxWaitMillis="10000" validationQuery="select 1"
            username="openkm" password="openkm" driverClassName="com.mysql.cj.jdbc.Driver"
            url="jdbc:mysql://localhost:3306/okmdb_test?allowPublicKeyRetrieval=true&autoReconnect=true&amp;useUnicode=true&amp;characterEncoding=UTF8&amp;serverTimezone=UTC"/>

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