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is there a way to perform insertion of an @Id-column value into a non @Id column when entity is being created/updated to avoid double-save-ing?

I am doing a study on the feasibility of a Spring Batch composed of two datasources. A SQL datasource for the Spring Batch metadata and a MongoDB datasource (with transactional use) for the business data. The transactional aspect raises several questions here.

The following topic: Spring batch with MongoDB and transactions and related resources provide a number of answers to my questions. The answer mentions the use of Spring's JtaTransactionManager to manage distributed transactions on the two datasources. This technique uses the 2PC protocol. It is also the most robust solution if I understood correctly. https://www.infoworld.com/article/2077963/distributed-transactions-in-spring--with-and-without-xa.html?page=2

On the other hand, I found some resources about Spring's ChainedTransactionManager. This technique uses the best effort 1PC protocol. This solution is less robust, if I understand correctly the system can be in an inconsistent state in case of a problem in the infrastructure (network failure for example). The ChainedTransactionManager has the advantage of being easier to implement and offers better performance. I saw that it is deprecated https://github.com/spring-projects/spring-data-commons/issues/2232.

What are the concrete risks of using the ChainedTransactionManager in a Spring Batch? In case of an error, can I have inconsistencies between the Spring batch metadata and the business data in Mongo? I imagine there are also considerations to take into account with retry or chunk skip strategies?

Thanks a lot for your help.

I'm trying to write a generic function to do some Webflux operations and I'm getting a class cast exception that I can't figure out

I'm working on Windows 10 pro, Java 1_8 or Java 1_15. No corporate proxy, connectivity to the internet works just fine.

I'm trying to build spring-boot from the source. I cloned the github repo, then checked out the tag that I needed.

Recently we run a test which created different Spring batch job instances concurrently (e.g 10 threads in parallel, job names are similar but different, e.g with the same prefix). And it's fairly easy to trigger deadlockerror reported from MySQL exception is

org.springframework.dao.DeadlockLoserDataAccessException: PreparedStatementCallback; SQL [INSERT into BATCH_JOB_INSTANCE(JOB_INSTANCE_ID, JOB_NAME, JOB_KEY, VERSION) values (?, ?, ?, ?)]; Deadlock found when trying to get lock; try restarting transaction; nested exception is com.mysql.jdbc.exceptions.jdbc4.MySQLTransactionRollbackException: Deadlock found when trying to get lock; try restarting transaction at org.springframework.jdbc.support.SQLErrorCodeSQLExceptionTranslator.doTranslate(SQLErrorCodeSQLExceptionTranslator.java:267) at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:72) at org.springframework.jdbc.core.JdbcTemplate.translateException(JdbcTemplate.java:1443) at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:633) at org.springframework.jdbc.core.JdbcTemplate.update(JdbcTemplate.java:862) at org.springframework.jdbc.core.JdbcTemplate.update(JdbcTemplate.java:917) at org.springframework.jdbc.core.JdbcTemplate.update(JdbcTemplate.java:922) at org.springframework.batch.core.repository.dao.JdbcJobInstanceDao.createJobInstance(JdbcJobInstanceDao.java:120) at org.springframework.batch.core.repository.support.SimpleJobRepository.createJobExecution(SimpleJobRepository.java:140) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:344)

We searched for existing reports regarding to deadlock and find that some are specific to SQLServer like this: (https://github.com/spring-projects/spring-batch/issues/1448). After analysis of the isolation level used for creating jobs(SERIALIZABLE) and the operation sequence, we think the deadlock could be trigged as following:

1、before creating a job instance, the code will first query batch_job_instance table to check if the instance already exists(about 3 times), under SERIALIZABLE mode, this will hold shared next-key lock (https://dev.mysql.com/doc/refman/5.7/en/innodb-next-key-locking.html) in MySQL which lock records that are in scope related to the job name.

2、thread 2 want to create job2 and insert a row in batch_job_instance and thread 3 want to do the same thing, as both threads hold the same read next-key lock and the rows that need to be inserted are also in the key scope, the deadlock will happen.

Refer to the link here(https://docs.spring.io/spring-batch/trunk/apidocs/org/springframework/batch/core/repository/support/AbstractJobRepositoryFactoryBean.html#setIsolationLevelForCreate-java.lang.String-), we tried changing the isolation level to REPEATABLE_READ and this worked without any deadlock.

So the key question here is :

Is setting isolation level to REPEATABLE_READ the recommended solution here and is there any side effect of this solution as it's not set as default option ?

Thanks a lot!

we plan to use Spring Batch for mission critical production batching system. And I am wondering which version we should choose now?

From the version history in github(https://github.com/spring-projects/spring-batch/tags): version 4.2.7 is marked with .RELEASE, while 4.3.3 is not.

So the questions are:

1、what's the difference regarding the versions with or without .RELEASE ending, is the ".RELEASE" ending verison more stable?

2、which version is recommended for production now ?
Thanks a lot!

I'm using spring-amqp's (latest version) rabbitTemplate.sendAndReceive(exchange, routingKey, message) method for sending messages. RabbitTemplate is configured with Jackson2JsonMessageConverter.

If I send a malformed json, I can see that message conversion fails with org.springframework.amqp.support.converter.MessageConversionException: Failed to convert Message content, as expected.

However, the sendAndReceive method doesn't abort and continues execution until a replyTimeout is hit. To compare, if there is an error in my @RabbitListener annotated method, then sendAndReceive aborts instantly and returns the exception.

Is there any way to tell spring to abort sendAndReceive in case of conversion exceptions?

In my Spring batch job, I'm trying to share data between steps using JobExecutionContext, which works only if i keep the steps single threaded as follows:

I am using Spring Data MongoDB and I have this simple repository: