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Re: [jta-dev] Enhancement of the @Transactional Annotation
Ah, thank you - I think I see better now a usage for read-only beyond if it is useful for the compliant implementation to make it's own optimizations (if it wants to to) in that it could also be made available to the application server via something on Transaction in https://jakarta.ee/specifications/platform/10/apidocs/jakarta/transaction/transactionmanager. That said, I am not sure how an application server would reliably use this information by pulling it from a transaction object - to help me understand better, if you are able and happy to do so, please can you share some pseudo-code showing where this information could theoretically be used?

On Tue, 6 Dec 2022 at 11:02, Christian Beikov <christian.beikov@xxxxxxxxx> wrote:

The `jakarta.transaction.Transaction` interface would ideally expose the read-only information, so that I can implement the optimizations in Hibernate for this case.

Am 06.12.2022 um 11:59 schrieb Benedict Eisenkrämer:

I think timeout and readOnly should be more straight forward:

For timeout the XAResource Interface provides a way to set it: https://docs.oracle.com/javase/8/docs/api/javax/transaction/xa/XAResource.html#setTransactionTimeout-int- It seems to be a optional feature of the underlying ResourceManager, so it would be nice to maybe log a warning in that.

For readOnly the main benefit is in what the specific implementaion makes of it (i.a. optimizations, as pointed out by Christian). I think the only requirement should be, that no entities may be updated, created or deleted. That way no work should be enlisted and the transaction can be commited as readonly.


For Isolation-Levels:

I do not 100% understand how the internals of the Transactional Implementation(s) work, but from my naive standpoint shouldn't it be possible to somehow acquire the currently used java.sql.Connection and just do something like this:

connection.setTransactionIsolation(Connection.TRANSACTION_READ_UNCOMMITTED);
connection.setReadOnly(true);

As under the hood surely jdbc is used as well, or am I wrong here?


On 06.12.22 10:45, Tom Jenkinson wrote:
Thank you for raising the topic!

I think an important consideration when adding things to Jakarta Transactions is what can the XAResource API support?

Rearding isolation levels, I don't think we have a way to inform the XAResource of isolation level and so adding that something like that to Jakarta Transactions it is not clear to me what an implementation would do with that information? Reading https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/transaction/annotation/Isolation.html#DEFAULT it seems intended to be specific to JDBC and so it seems maybe Spring has a way to merge a concept of datasource with their Transactional annotation? I am not sure the same would be appropriate for Jakarta Transactions.

On Sun, 4 Dec 2022 at 15:44, Benedict Eisenkrämer <benedict@xxxxxxxxxxxxxx> wrote:

Hello there,

I am new to this mailing list so maybe a few short words to myself first: I am a Software Engineer in Germany responsible for our JavaEE, soon to be JakartaEE framework. I am quiet interested in  JakartaEE and its development.

The topic I would like to discuss is the enhancement of the @Transactional Annotation for JakartaEE 11. A good template would be the Spring specific Annotation of the same name which supports among other things :

  • Isolation levels
  • timeout
  • readOnly

I already found a issue on github regarding the Topic, which unfortunately has not seen any attention given to it since 2016. So I wanted to spark a discussion.

In my opinion these enhancement could be quiet helpful.


Thanks in advance and best regards

Benedict Eisenkrämer

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