具有多个数据源Oracle和H2的Spring Boot

Question

I develop a spring boot RestController for my angular Project and encountered a problem. In my logic for the rest-service I used two different databases to get data from.

Here you can see the datasource configuration:

[application.properties]

#datasource1
spring.datasource.url=[url]
spring.datasource.username=[username]
spring.datasource.password=[password]
spring.datasource.driverClassName=org.h2.Driver

#datasource2
spring.secondDatasource.url=[url]
spring.secondDatasource.username=[username]
spring.secondDatasource.password=[password]
spring.secondDatasource.driverClassName=oracle.jdbc.OracleDriver

[DatasourceConfig.java]

@Bean
@Primary
@ConfigurationProperties(prefix="spring.datasource")
public DataSource h2DataSource() {
    return DataSourceBuilder.create().build();
}

@Bean
@ConfigurationProperties(prefix="spring.secondDatasource")
public DataSource oracleDataSource() {
    return DataSourceBuilder.create().build();
}

Logging output: (No Exceptions are ever thrown for this problem)

...
2016-11-22 13:20:25.853 [INFO ] 1  [main] d.b.s.Application : Started Application in 7.757 seconds (JVM running for 12.515)
2016-11-22 13:20:31.731 [INFO ] 62 [http-nio-8080-exec-1] o.s.w.s.DispatcherServlet : FrameworkServlet 'dispatcherServlet': initialization started
2016-11-22 13:20:31.757 [INFO ] 62 [http-nio-8080-exec-1] o.s.w.s.DispatcherServlet : FrameworkServlet 'dispatcherServlet': initialization completed in 26 ms
2016-11-22 13:20:34.984 [INFO ] 65 [http-nio-8080-exec-5] d.b.s.r.RESTclient : /rest/getMyData
2016-11-22 13:20:34.992 [INFO ] 63 [http-nio-8080-exec-2] d.b.s.r.RESTclient : /rest/getMyData2
2016-11-22 13:20:34.993 [INFO ] 69 [http-nio-8080-exec-8] d.b.s.r.RESTclient : /rest/getMyData3
2016-11-22 13:20:35.004 [DEBUG] 65 [http-nio-8080-exec-5] d.b.s.DataSourceService : getH2Connection()
2016-11-22 13:20:35.022 [DEBUG] 63 [http-nio-8080-exec-2] d.b.s.DataSourceService : getOracleConnection()
2016-11-22 13:20:35.022 [DEBUG] 69 [http-nio-8080-exec-8] d.b.s.DataSourceService : getH2Connection()

The problem is, that every used worker thread (http-nio-8080-?, ...) for the rest-service hangs up at datasource.getConnection() in my DataSourceService. It freeze forever and waits for a Connection that can't be get.

@Service
public class DataSourceService {
    private final DataSource h2DataSource;
    private final DataSource oracleDataSource;

    @Autowired
    public DataSourceService(DataSource h2DataSource, DataSource oracleDataSource) {
        this.h2DataSource = h2DataSource;
        this.oracleDataSource = oracleDataSource;
    }

    public Connection getH2Connection() throws SQLException {
        LoggerUtil.logDebug(getClass(), "getH2Connection()");
        return h2Connection.getConnection();
    }

    public Connection getOracleConnection() throws SQLException {
        LoggerUtil.logDebug(getClass(), "getOracleConnection()");
        return oracleConnection.getConnection();
    }
}

The strange thing about it is, that sometimes it works without ever changed a line of code (5% of all times) and mostly (95% of all times) it hangs up.

in my pom.xml I have following database driver dependencies:

<dependency>
    <groupId>com.oracle</groupId>
    <artifactId>ojdbc6</artifactId>
    <version>11.2.0.4</version>
    <scope>runtime</scope>
</dependency>
<dependency>
    <groupId>com.h2database</groupId>
    <artifactId>h2</artifactId>
    <version>1.4.193</version>
    <scope>runtime</scope>
</dependency>

If all datasources have the same driver, this will never happen, but in combination I found this strange behavior.

My ideas are that this only happen if the h2Database is initialized before the oracle. At this point the spring classloader loads the h2-driver classes and they will be cached. At next the oracle gets initialized and some classes are to close identical, so that some of the h2-classes are used for oracle. Because of that, the strange state of freeze is created. (perhaps also vice versa).

My question now: Why can't I use the H2 and Oracle database at the same time with Spring-boot?

EDIT:

After some debugging I have found more informations:

[org.apache.tomcat.jdbc.pool.ClassLoaderUtil]

Row 29:  loadClass(...)
...
Row 38: return Class.forName(className, true, cl);  //className: "oracle.jdbc.OracleDriver"  cl: Launcher$AppClassLoader

In ClassLoaderUtil is a lookup for Driver-Class by className. The className "org.h2.Driver" can be resolved without problem, but "oracle.jdbc.OracleDriver" don't.

After that I have made a thread dump where you can see the points for stuck. At this time there are 5 stucked threads which stucked at different positions.

http-nio-8080-exec-2@8307 (runnable) (is using only oracle database)

"http-nio-8080-exec-2@8307" daemon prio=5 tid=0x40 nid=NA runnable
  java.lang.Thread.State: RUNNABLE
     blocks http-nio-8080-exec-6@8311
      at java.lang.Class.forName0(Class.java:-1)
      at java.lang.Class.forName(Class.java:348)
      at org.apache.tomcat.jdbc.pool.ClassLoaderUtil.loadClass(ClassLoaderUtil.java:38)
      at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:271)
      at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:203)
      at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:718)
      at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:650)
      at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:468)
      at org.apache.tomcat.jdbc.pool.ConnectionPool.<init>(ConnectionPool.java:143)
      at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:118)
      - locked <0x2139> (a org.apache.tomcat.jdbc.pool.DataSource)
      at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:107)
      at org.apache.tomcat.jdbc.pool.DataSourceProxy.getConnection(DataSourceProxy.java:131)
      at d.b.s.DataSourceService.getConnection(DataSourceService.java:51)                        //<-- That's my package
      ...

http-nio-8080-exec-3@8308 (runnable) (comparison between oracle and h2 data)

"http-nio-8080-exec-3@8308" daemon prio=5 tid=0x41 nid=NA runnable
  java.lang.Thread.State: RUNNABLE
  at oracle.jdbc.driver.OracleDriver.<clinit>(OracleDriver.java:190)
  at java.lang.Class.forName0(Class.java:-1)
  at java.lang.Class.forName(Class.java:348)
  at org.apache.tomcat.jdbc.pool.ClassLoaderUtil.loadClass(ClassLoaderUtil.java:38)
  at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:271)
  at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:203)
  at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:718)
  at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:650)
  at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:468)
  at org.apache.tomcat.jdbc.pool.ConnectionPool.<init>(ConnectionPool.java:143)
  at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:118)
  - locked <0x213d> (a org.apache.tomcat.jdbc.pool.DataSource)
  at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:107)
  at org.apache.tomcat.jdbc.pool.DataSourceProxy.getConnection(DataSourceProxy.java:131)
  at d.b.s.DataSourceService.getConnection(DataSourceService.java:51)
  ...

http-nio-8080-exec-4@8309 (runnable) (comparison between oracle and h2 data)

(same as exec-2)

http-nio-8080-exec-5@8310 (runnable) (is using only h2 database)

"http-nio-8080-exec-5@8310" daemon prio=5 tid=0x43 nid=NA runnable
   java.lang.Thread.State: RUNNABLE
  at sun.reflect.GeneratedConstructorAccessor109.newInstance(Unknown Source:-1)
  at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:-1)
  at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
  at java.lang.Class.newInstance(Class.java:442)
  at java.util.ServiceLoader$LazyIterator.nextService(ServiceLoader.java:380)
  at java.util.ServiceLoader$LazyIterator.next(ServiceLoader.java:404)
  at java.util.ServiceLoader$1.next(ServiceLoader.java:480)
  at java.sql.DriverManager$2.run(DriverManager.java:603)
  at java.sql.DriverManager$2.run(DriverManager.java:583)
  at java.security.AccessController.doPrivileged(AccessController.java:-1)
  at java.sql.DriverManager.loadInitialDrivers(DriverManager.java:583)
  at java.sql.DriverManager.<clinit>(DriverManager.java:101)
  at org.h2.Driver.load(Driver.java:155)
  at org.h2.Driver.<clinit>(Driver.java:41)
  at java.lang.Class.forName0(Class.java:-1)
  - locked <0x211b> (a java.lang.Class)
  at java.lang.Class.forName(Class.java:348)
  at org.apache.tomcat.jdbc.pool.ClassLoaderUtil.loadClass(ClassLoaderUtil.java:38)
  at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:271)
  at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:203)
  at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:718)
  at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:650)
  at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:468)
  at org.apache.tomcat.jdbc.pool.ConnectionPool.<init>(ConnectionPool.java:143)
  at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:118)
  at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:107)
  at org.apache.tomcat.jdbc.pool.DataSourceProxy.getConnection(DataSourceProxy.java:131)
  - locked <0x20e9> (a org.apache.tomcat.jdbc.pool.DataSource)
  at d.b.s.DataSourceService.getConnection(DataSourceService.java:51)
  ...

http-nio-8080-exec-6@8311 (waiting for monitor entry) (comparison between oracle and h2 data)

"http-nio-8080-exec-6@8311" daemon prio=5 tid=0x44 nid=NA waiting for monitor entry
   java.lang.Thread.State: BLOCKED
 waiting for http-nio-8080-exec-2@8307 to release lock on <0x2139> (a org.apache.tomcat.jdbc.pool.DataSource)
  at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:115)
  at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:107)
  at org.apache.tomcat.jdbc.pool.DataSourceProxy.getConnection(DataSourceProxy.java:131)
  at d.b.s.DataSourceService.getConnection(DataSourceService.java:51)
  ...

Answer 1

I have meet the same question like you, but in h2 and mysql.I am not use h2 and oracle at same time, in this post , maybe you can find some useful.

Here is my double datasource config:

maven dependency:

<!-- stater mybatis --> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>1.1.1</version> </dependency> <!-- jdbc --> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <scope>runtime</scope> </dependency>

```

datasource:
  km:
    driverClassName: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/km?useUnicode=true&characterEncoding=UTF-8&useSSL=false
    username: root
    password: 123456
    max-active: 100
    max-idle: 10
    max-wait: 10000
    test-while-idle: true
  esb:
    driverClassName: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/esb?useUnicode=true&characterEncoding=UTF-8&useSSL=false
    username: root
    password: 123456
    max-active: 100
    max-idle: 10
    max-wait: 10000
    test-while-idle: true

```

Datasource km config class: ```

import com.package.km.api.commons.config.datasource.annotation.UseDatasourceKM;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.annotation.MapperScan;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.core.io.ClassPathResource;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;

import javax.sql.DataSource;
import java.lang.invoke.MethodHandles;
import java.sql.SQLException;

/**
 * km datasource config
 * Created by BeeNoisy on 16/5/23.
 */
@Configuration
@MapperScan(basePackages = "package.km", annotationClass = UseDatasourceKM.class, sqlSessionFactoryRef = KMDatasourceConfig.SQL_SESSION_FACTORY_NAME)
public class KMDatasourceConfig {
    public static final String SQL_SESSION_FACTORY_NAME = "sessionFactoryKm";
    public static final String TX_MANAGER = "txManagerKm";
    private static final Logger logger = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());

    @Bean(name = "datasourceKm")
    @Primary
    @ConfigurationProperties(prefix = "datasource.km")
    public DataSource dataSourceKm() {
        return DataSourceBuilder.create().build();
    }

    @Bean(name = TX_MANAGER)
    @Primary
    public PlatformTransactionManager txManagerKm() {
        return new DataSourceTransactionManager(dataSourceKm());
    }

    @Bean(name = KMDatasourceConfig.SQL_SESSION_FACTORY_NAME)
    @Primary
    public SqlSessionFactory sqlSessionFactoryBean() throws Exception {

        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setConfigLocation(new ClassPathResource("/mybatis/mybatis-conf.xml"));
        sqlSessionFactoryBean.setDataSource(dataSourceKm());
        return sqlSessionFactoryBean.getObject();
    }
}

```

Here is datasource esb config class:

```

import com.package.km.api.commons.condition.EsbEnabledCondition;
import com.package.km.api.commons.config.datasource.annotation.UseDatasourceESB;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.annotation.MapperScan;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Conditional;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.ClassPathResource;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;

import javax.sql.DataSource;
import java.lang.invoke.MethodHandles;

/**
 * Created by BeeNoisy on 16/5/23.
 */
@Configuration
@Conditional(EsbEnabledCondition.class)
@MapperScan(basePackages = "package.esb", annotationClass = UseDatasourceESB.class, sqlSessionFactoryRef = EsbDatasourceConfig.SQL_SESSION_FACTORY_NAME)
public class EsbDatasourceConfig {
    public static final String SQL_SESSION_FACTORY_NAME = "sessionFactoryEsb";
    public static final String TX_MANAGER = "txManagerEsb";
    private static final Logger logger = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());

    @Bean(name = "datasourceEsb")
    @Conditional(EsbEnabledCondition.class)
    @ConfigurationProperties(prefix = "datasource.esb")
    public DataSource dataSourceEsb() {
        return DataSourceBuilder.create().build();
    }

    @Bean(name = TX_MANAGER)
    @Conditional(EsbEnabledCondition.class)
    public PlatformTransactionManager txManagerEsb() {
        return new DataSourceTransactionManager(dataSourceEsb());
    }

    @Bean(name = EsbDatasourceConfig.SQL_SESSION_FACTORY_NAME)
    @Conditional(EsbEnabledCondition.class)
    public SqlSessionFactory sqlSessionFactoryBean() throws Exception {

        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setConfigLocation(new ClassPathResource("/mybatis/mybatis-conf.xml"));
        sqlSessionFactoryBean.setDataSource(dataSourceEsb());
        return sqlSessionFactoryBean.getObject();
    }
}

```

Then you can use the two annotation: UseDatasourceESB or UseDatasourceKM to annotate your mapper class like:

```

@UseDatasourceKM
public interface GroupBaseDAO {
    public static final String COL_ALL = " id, name, create_time, last_update_time "; 
    public static final String TABLE = " group_base "; 

    @Select(" select " + COL_ALL + " from " + TABLE + " where id = #{id} ")
    public GroupBase findById(@Param("id") int id);

    @Select(" select " +
            COL_ALL +
            " from " +
            TABLE +
            " where id < #{lastId} " +
            " limit #{count} ")
    public List<GroupBase> list(
            @Param("lastId") int lastId,
            @Param("count") int count
    );
...

```

There is two datasource in mysql\\h2 and oracle. y the way, you can run your code in debug model, and step into getConnection() method to find more details.