Cosmos DB API for MongoDB: Transaction support on Shard key collection

Question

Hello,

We're using the Cosmos DB API for MongoDB. I just wonder how can we do the transactions on Shard key collection, what is the best practice?

I am using spring boot with spring data jpa.

My expectation is, processMessage() method should not update the count.

@Bean
public MongoTransactionManager transactionManager(MongoDatabaseFactory dbFactory) {
    return new MongoTransactionManager(dbFactory);
}

@Transactional(rollbackFor = RuntimeException.class)
public void processMessage( final TestEntity testEntity) {
    try {
        testEntity.setCount(testEntity.getCount() + 10);
        testRepository.save(testEntity);
        if(true){
            throw new RuntimeException("Error in processing the record");
        }
}

implementation 'org.springframework.boot:spring-boot-starter-data-mongodb'

Answer 1

Hi @manideep krishna

I'm glad that you were able to resolve your issue and thank you for posting your solution so that others experiencing the same thing can easily reference this! Since the Microsoft Q&A community has a policy that "The question author cannot accept their own answer. They can only accept answers by others ", I'll repost your solution in case you'd like to "Accept " the answer.

Issue:

Hello,

We're using the Cosmos DB API for MongoDB. I just wonder how can we do the transactions on Shard key collection, what is the best practice?

I am using spring boot with spring data jpa.

My expectation is, processMessage() method should not update the count.

@Bean
public MongoTransactionManager transactionManager(MongoDatabaseFactory dbFactory) {
    return new MongoTransactionManager(dbFactory);
}

@Transactional(rollbackFor = RuntimeException.class)
public void processMessage( final TestEntity testEntity) {
    try {
        testEntity.setCount(testEntity.getCount() + 10);
        testRepository.save(testEntity);
        if(true){
            throw new RuntimeException("Error in processing the record");
        }
}

implementation 'org.springframework.boot:spring-boot-starter-data-mongodb'

Solution:

this below worked for me.

@Bean

@Transactional

If you have any other questions or are still running into more issues, please let me know. Thank you again for your time and patience throughout this issue.

Please remember to "Accept Answer" if any answer/reply helped, so that others in the community facing similar issues can easily find the solution.

Answer 2

Hi @manideep krishna

If your operations are limited to single documents, Cosmos DB ensures atomicity for single-document transactions even in sharded collections.

If you need to perform multi-document transactions on a sharded collection, consider restructuring your data to fit within a single collection or implementing rollback logic at the application level.

Please go through these Documentation link and similar thread link that might help you:

https://learn.microsoft.com/en-us/azure/cosmos-db/mongodb/use-multi-document-transactions

https://learn.microsoft.com/en-us/answers/questions/751204/cosmos-db-api-for-mongodb-transaction-support-on-m

Hope this helps. Do let us know if you any further queries.

Answer 3

this below worked for me.

@Bean
public MongoTransactionManager transactionManager(MongoDatabaseFactory dbFactory) {
    return new MongoTransactionManager(dbFactory); 
} 

@Transactional
public void processMessage( final TestEntity testEntity) {
    try {
        testEntity.setCount(testEntity.getCount() + 10);
        testRepository.save(testEntity);
        if(true){
            throw new RuntimeException("Error in processing the record");
        }
}