JPA EntityManagerFactory with AbstractRoutingDataSource containing multiple DB vendors? - spring-data-jpa

So I have a perfectly good working example of using AbstractRoutingDataSource and JdbcTemplate with Oracle / Sybase & MsSql databases in the same running spring boot application. I use AOP and a custom annotation on the method so that it sets the data source name on the thread and then the AbstractDataSource hands the correct data source to JdbcTemplate when you run a query.
Now the issue I am facing, is how I go about configuring the hibernate dialects when configuring the EntityManagerFactoryBuilder, as these are obviously different and based on the underlying active data sources (can differ between environments). The code you would use to configure the EntityManagerFactory if all data sources were the same would be as follows.
#Bean
public LocalContainerEntityManagerFactoryBean entityManagerFactory(EntityManagerFactoryBuilder builder) {
return builder
.dataSource(dataSource)
.packages("<the associated entity package name>")
.build();
But when I start the spring boot application, I get the error below
Caused by: org.hibernate.HibernateException: Access to DialectResolutionInfo cannot be null when 'hibernate.dialect' not set
Anyone know a workaround for this or is it not possible to have the same JPA Entities and CrudRepository instances spread across multiple datasources with different vendors?

Related

What is a schema manager in Spring's Hibernate and how I set it?

Some tables were dropped at development environment during a spring-data-jpa project test and the developer responsible for it said it only used spring.jpa.hibernate.ddl-auto=update. Checking here, I suspected he had it set as create-drop, but since he said he didn't use, I went for this piece of information:
Spring Boot chooses a default value for you based on whether it thinks your database is embedded.
It defaults to create-drop if no schema manager has been detected
Since his application actually managed to connect to our development environment PostgreSQL database (since it dropped some tables), I start to think he maybe could have forgotten to set hbm2ddl.auto and automatically it went as create-drop.
Is it possible to connect to PostgreSQL and don't have a valid schema manager defined? Which are the most common schema managers?
PS: at this application #DataSource is set this way:
#Bean
public DataSource dataSource() {
Class.forName("org.postgresql.Driver");
DriverManagerDataSource dataSource = new DriverManagerDataSource();
dataSource.setUrl(someUrlConnectionStringFromApplicationDotPropertiesFile);
return dataSource;
}
like String someUrlConnectionStringFromApplicationDotPropertiesFile = "jdbc:postgresql://ipAddress:port/dbName?user=user&password=pass". I know spring-data-jpa sets everything with spring jpa properties automatically without this method, this is currently an unchangeable legacy code :(
Spring Boot said they are Higher-level Database Migration Tool (Flyway or Liquibase).
ref: https://docs.spring.io/spring-boot/docs/2.7.x/reference/html/howto.html#howto.data-access.jpa-properties, https://docs.spring.io/spring-boot/docs/2.7.x/reference/html/howto.html#howto.data-access.jpa-properties
You can also configure them through Spring Boot documentation or their own docs. ref: https://docs.spring.io/spring-boot/docs/2.7.x/reference/html/howto.html#howto.data-initialization.migration-tool
For example, configure Flyway community version through maven (https://flywaydb.org/download/community):
<build>
...
<plugin>
<groupId>org.flywaydb</groupId>
<artifactId>flyway-maven-plugin</artifactId>
<version>9.12.0</version>
</plugin>
...
</build>

Can Jpa transaction and jdbc transaction use same datasource

I have a code which uses Hibernate Jpa transaction and an independent scheduler is written which uses jdbctransaction . My application context xml has both org.springframework.orm.jpa.JpaTransactionManager and org.springframework.jdbc.datasource.DataSourceTransactionManager beans. Can both the transaction managers use same datasource defined in xml. Or do I need to create a new datasource bean for jdbc transaction

Can't use #Transactional in Spring Boot Test

I've created a simple application using Spring Boot, Kotlin & Mongodb. Now I would like to use the #Transactional annotation in the test CustomerServiceIntegrationTest to make sure each test case rolls back any changes it did to the database.
When I add #Transactional I get the message Failed to retrieve PlatformTransactionManager for #Transactional test.
Writing to the db otherwise works fine.
What did I miss?
https://github.com/urswiss/customer

Possibility to use JPA without EJB inside WebSphere module

I have a WebSphere ESB 7.5 hosting a web service (inside a mediation module).
The data from the web service should be stored to a DB. DB access should be performed via JPA.
I would like to utilize JPA with WebSphere's container-managed transactions (so JPA just replaces plain SQL calls and that's it). I don't want to generate an EJB from this tutorial. This seems unnecessary for my case.
Is it possible? Any code example?
There is nothing in the JPA specification that mandates it be used in an application container or via EJB's. But, as to your second condition, container managed transactions are defined at the level of the container, and more specifically, they are only valid for use in entity beans. So, your options are to use:
JPA + non-entity beans + user transactions
JPA + entity beans + container managed transaction.

How to use Apache-Commons DBCP with EclipseLink JPA and Tomcat 7.x

I've been working on a web application, deployed on Tomcat 7, which use EclipseLink JPA to handle the persistence layer.
Everything works fine in a test environment but we're having serious issues in the production environment due to a firewall cutting killing inactive connections. Basically if a connection is inactive for a while a firewall the sits between the Tomcat server and the DB server kill it, with the result of leaving "stale" connections in the pool.
The next time that connection is used the code never returns, until it gets a "Connection timed out" SQLException (full ex.getMessage() below).
EL Fine]: 2012-07-13
18:24:39.479--ServerSession(309463268)--Connection(69352859)--Thread(Thread[http-bio-8080-exec-5,5,main])--
MY QUERY REPLACED TO POST IT TO SO [EL Config]: 2012-07-13
18:40:10.229--ServerSession(309463268)--Connection(69352859)--Thread(Thread[http-bio-8080-exec-5,5,main])--disconnect
[EL Info]: 2012-07-13
18:40:10.23--UnitOfWork(1062365884)--Thread(Thread[http-bio-8080-exec-5,5,main])--Communication
failure detected when attempting to perform read query outside of a
transaction. Attempting to retry query. Error was: Exception
[EclipseLink-4002] (Eclipse Persistence Services -
2.3.0.v20110604-r9504): org.eclipse.persistence.exceptions.DatabaseException Internal
Exception: java.sql.SQLException: Eccezione IO: Connection timed out
I already tried several configuration in the persistence.xml, but since I have no access to the firewall configuration I had no luck with these methods. I also tried to use setCheckConnections()
ConnectionPool cp = ((JpaEntityManager)em).getServerSession().getDefaultConnectionPool();
cp.setCheckConnections();
cp.releaseConnection(cp.acquireConnection());
I managed to solve the issue in a test script using testOnBorrow, testWhileIdle and other features that are avalaible from DBCP Apache Commons. I'd like to know how to override the EclipseLink internal connection pool to use a custom connection pool so that I can provide an already configured pool, based on DBCP rather than just configuring the internal one using persistence.xml.
I know I should provide a SessionCustomizer, I'm uncertain which one is the correct pattern to use. Basically I would like to preserve the performance of DBCP in a JPA-like way.
I'm deploying on Tomcat 7, I know that if I switch to GF I won't have this problem, but for a matter of consistency with other webapp on the same server I'd prefere to stay on Tomcat.
What you want is definitely possible, but you might be hitting the limits of the "do it yourself" approach.
This is one of the more difficult things to explain, but there are effectively two ways to configure your EntityManagerFactory. The "do it yourself" approach and the "container" approach.
When you call Persistence.createEntityManagerFactory it eventually delegates to this method of the PersistenceProvider interface implemented by EclipseLink:
EntityManagerFactory createEntityManagerFactory(String emName, Map map)
The deal here is EclipseLink will then take it upon itself to do all the work, including its own connection creation and handling. This is the "do it yourself" approach. I don't know EclipseLink well enough to know if there is a way to feed it connections using this approach. After two days on Stackoverflow it doesn't seem like anyone else has that info either.
So here is why this "works in GF". When you let the container create the EntityManagerFactory for you by having it injected or looking it up, the container uses a different method on the PersistenceProvider interface implemented by EclipseLink:
EntityManagerFactory createContainerEntityManagerFactory(PersistenceUnitInfo info, Map map)
The long and short of it is that this PersistenceUnitInfo is an interface that the container implements and has these two very key methods on it:
public DataSource getJtaDataSource();
public DataSource getNonJtaDataSource();
With this mode EclipseLink will not try to do its own connection handling and will simply call these methods to get the DataSource from the container. This is really what you need.
There are two possible approaches you could take to solving this:
You could attempt to instantiate the EclipseLink PersistenceProvider implementation yourself and call the createContainerEntityManagerFactory method passing in your own implementation of the PersistenceUnitInfo interface and feed the DBCP configured DataSource instances into EclipseLink that way. You would need to parse the persistence.xml file yourself and feed that data in through the PersistenceUnitInfo. As well EclipseLink might also expect a TransactionManager, in which case you'll be stuck unless you hunt down a TransactionManager you can add to Tomcat.
You could use the Java EE 6 certified version of Tomcat, TomEE. DataSources are configured in the tomee.xml, created using DBCP with full support for all the options you need, and passed to the PersistenceProvider using the described createContainerEntityManagerFactory call. You then get the EntityManagerFactory injected via #PersistenceUnit or look it up.
If you do attempt to use TomEE, make sure your persistence.xml is updated to explicitly set transaction-type="RESOURCE_LOCAL" because the default is JTA. Even though it's non-compliant to use JTA with the Persistence.createEntityManagerFactory approach, there aren't any persistence providers that will complain and let you know you're doing something wrong, they treat it as RESOURCE_LOCAL ignoring the schema. So when you go to port your app to an actual certified server, it blows up.
Another note on TomEE is that in the current release, you'll have to put your EclipseLink libs in the <tomcat>/lib/ directory. This is fixed in trunk, just not released yet.
I'm not sure how useful these slides will be without the explanation that goes along with them, but the second part of this presentation is a deep dive into how container-managed EntityManager's work, specifically with regards to connection handling and transactions. You can ignore the transaction part as you aren't using them and already have an in production you're not likely to dramatically change, but it might be interesting for future development.
Best of luck!