HibernateException: hibernate.dialect not set, but I did set it in application.properties

Question

I am working on a Spring Boot application that uses a number of databases. I define datasources, I define entitymanagers, and I keep getting this error

org.hibernate.HibernateException: Access to DialectResolutionInfo cannot be null when 'hibernate.dialect' not set
at org.hibernate.engine.jdbc.dialect.internal.DialectFactoryImpl.determineDialect(DialectFactoryImpl.java:100)
at org.hibernate.engine.jdbc.dialect.internal.DialectFactoryImpl.buildDialect(DialectFactoryImpl.java:54)
at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:137)
at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:35)
at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.initiateService(StandardServiceRegistryImpl.java:94)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:263)

This is the @Configuration file for one database:

@Configuration
public class CustomerDbConfig {

@Bean
public DataSource dataSource() {
    return DataSourceBuilder.create().build();
}

@Bean(name = "customerEntityManager")
@PersistenceContext(unitName = "customerEntityManager")
public LocalContainerEntityManagerFactoryBean customerEntityManagerFactory(
        EntityManagerFactoryBuilder builder, DataSource dataSource) {
    return builder.dataSource(dataSource).packages("com.example.report_service").build();
}

@Bean
public JpaTransactionManager transactionManager(EntityManagerFactory emf) {
    JpaTransactionManager jpaTransactionManager = new JpaTransactionManager();
    jpaTransactionManager.setEntityManagerFactory(emf);
    return jpaTransactionManager;
}

@Bean
public EntityManagerFactoryBuilder entityManagerFactoryBuilder() {
    return new EntityManagerFactoryBuilder(new HibernateJpaVendorAdapter(), new HashMap<>(), null);
}

}

and these are the application.properties

spring.datasource.url=jdbc:postgresql://dv1.example.com:5432/customer
spring.datasource.username=${DATABASECUSTOMERUSERNAME:customer}
spring.datasource.password=${DATABASECUSTOMERPASSWORD:customer}
spring.datasource.driver-class-name=org.postgresql.Driver
spring.datasource.hikari.minimum-idle=2
spring.datasource.hikari.maximum-pool-size=${MAX_POOL_SIZE:20}
spring.datasource.tomcat.validation-query=SELECT 1
spring.datasource.tomcat.validation-query-timeout=5000
spring.datasource.tomcat.test-on-borrow=true
spring.datasource.tomcat.test-on-connect=true
spring.transaction.default-timeout=${TRANSACTION_TIMEOUT:3600}
spring.jpa.properties.hibernate.proc.param_null_passing=true
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.PostgreSQLDialect
spring.jpa.properties.hibernate.jdbc.lob.non_contextual_creation= true
spring.jpa.open-in-view=false
spring.jpa.show-sql=true
spring.jpa.properties.hibernate.format_sql=true
spring.jpa.properties.hibernate.show_sql=false
spring.jpa.properties.hibernate.use_sql_comments=true
spring.jpa.properties.hibernate.type=trace
spring.autoconfigure.exclude=org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration

When I explicitely set a persistenceUnit name in the entitymanager, the error changes, it complains about not finding a PU with the name I specified.

I limited my application to having only one database, trying to figure out what's happening. When I remove the configuration file there's no issues. What makes this application special is that it uses native queries only, it doesn't have @Entity classes because the database is updated by other applictions. When I remove the .packages(..) part from the code, it complaines like

No persistence units parsed from {classpath*:META-INF/persistence.xml}

I suspect the issue is related to the fact that we don't have classes that need to be scanned.

Edit: Following M.Deinum's answer, I replaced the config by

@Configuration
@EnableTransactionManagement
public class CustomerDbConfig {

@ConfigurationProperties(prefix = "customer.datasource")
@Bean(name = "customer-datasource")
public DataSource dataSource() {
    return DataSourceBuilder.create().build();
}

@Bean(name = "customer-jdbcTemplate")
public JdbcTemplate primaryJdbcTemplate(@Qualifier("customer-datasource") DataSource dataSource) {
    return new JdbcTemplate(dataSource);
}

}

and I use the four templates in the daos. Works like a charm.

Answer 1

When using JPA you need entities. Using the JPA classes to just execute SQL queries is overkill. Just use a plain Jdbctemplate or NamedParameterJdbcTemplate for that.