Transaction question with multiple cache.

[seto]

Is the transaction related to a specific cache?

I try the code below.

getIdCache().getAdvancedCache().getTransactionManager().begin();
getKeyCache().getAdvancedCache().getTransactionManager().begin();

But I get the exception below.

Thread[pool-6-thread-1,5,main] is already associated with a transaction (DummyTransaction{xid=DummyXid{id=1}, status=0})

[vladsz83]

Probably because transaction is bound to the calling thread. I guess the caches share the same transaction manager, so it can’t open transaction twice.

[seto]

Vlad St wrote:

Probably because transaction is bound to the calling thread. I guess the caches share the same transaction manager, so it can’t open transaction twice.

Does it actually share transaction?

What if with requirements that treat multiple caches separately?

[rvansa]

Yes, these are JTA transactions bound to current thread, so they're shared between caches and possibly another resources that register to it (e.g. DB connection, JMS...).

You can temporarily suspend a transaction using TransactionManager.suspend(), start another one and later resume it using TransactionManager.resume().

[seto]

Radim Vansa wrote:

Yes, these are JTA transactions bound to current thread, so they're shared between caches and possibly another resources that register to it (e.g. DB connection, JMS...).

You can temporarily suspend a transaction using TransactionManager.suspend(), start another one and later resume it using TransactionManager.resume().

Thank you for your clarifying. For now I can use one begin and one commit or one rollback. But I may have requirements for separate transaction in the future.

But if I want to do stuffs this. Maybe a and b fail and rollback. But keep the c and d. Then it's not an easy way to suspend and resume.

acache.transaction.start

bcache.transaction.start

ccache.transaction.start

dcache.transaction.start

try{

// do something with a b c d cache

// which is wrote by users of my library

acache.transaction.commit

bcache.transaction.commit

}catch(e)

{

acache.transaction.rollback

bcache.transaction.rollback

}

try{

// I do something myself

ccache.transaction.commit

dcache.transaction.commit

}catch(e)

{

ccache.transaction.rollback

dcache.transaction.rollback

}

[seto]

And also, can anyone tell me how to use JBossStandaloneJTAManagerLookup programmatically? I can use dummy only.

When I use the code below, it will report execption below.

builder.transaction().transactionManagerLookup(new JBossStandaloneJTAManagerLookup());

Exception in thread "main" org.infinispan.commons.CacheException: This is transactional cache but no transaction manager could be found. Configure the transaction manager lookup properly.

[rvansa]

You want users of your library to participate on two independent transactions, and determining which transaction should given operation be applied to according to the cache? I guess that in that case you have to create a wrapper for the exposed API (e.g. Cache if you're exposing that directly) that will automatically choose which transaction should it resume.

There's no easier way because this is not a common usecase, e.g. using CMT,  all operations within a container-invoked method belong to single transaction. In the example, what's your reason to deal with independent transactions for cache A and B, instead of using single transaction to wrap whole user operation?

Also note that your approach does not give you ACIDity - if dcache.transaction fails to commit, rolling back ccache.transaction has no effect, since it has been already comitted. Also you're losing some possibilities to optimize the transaction.

[seto]

Thank you. I'm wrapping the API. I can know which to choose. For now, I'll use a share transaction for now.

And also JBossStandaloneJTAManagerLookup working now after I add the following dependencies.

compile "org.jboss.spec.javax.transaction:jboss-transaction-api_1.2_spec"
compile "org.jboss:jboss-transaction-spi:${jboss_transaction_spiVersion}"
compile "org.jboss.narayana.jta:narayana-jta:${narayanaVersion}"

[vladsz83]

Try something like this:

EmbeddedCacheManager manager = new DefaultCacheManager(...);

JBossStandaloneJTAManagerLookup jBossStandaloneJTAManagerLookup = new JBossStandaloneJTAManagerLookup();

jBossStandaloneJTAManagerLookup.init(manager.getCacheManagerConfiguration());

transactionManagerLookup = jBossStandaloneJTAManagerLookup;

manager.getDefaultCacheConfiguration().transaction()

  .transactionManagerLookup(transactionManagerLookup);