ERROR: could not serialize access due to concurrent update

Question

Hi.
I use ejb+glassfish+postgres in my project.
The project is a web application for finansial data transfering.
I have three DBs, long global transactions, serializable isolation level, container-managed transaction.
When i test the project with concurent threads, i get an exception: "ERROR: could not serialize access due to
concurrent update"
I read that when you get suck kind of error, your program must rollback current transaction and then reply this transaction.
what do i need to do to complete this transaction? :
1) rollback and reply transaction
2) maybe, the are other ways to reply transaction (for example: glassfish configurations, ....)
Edited by: 856539 on 04.05.2011 8:10

Answer 1

If your DAO is nicely separated from your service layer as it should be then the solution I suggested above works and doesn't require you to change many classes because you can catch the expection in the DAO layer and do the retry in the DAO layer. That's where the solution belongs too because it's only applicable for your current database solution (Postgres). i.e If you change your database solution you need to change your DAO anyway, but only your DAO. If you put the solution in your service layer (or client layer) then you need to change those layers when you change your database solution which defeats the purpose of the separation.
If you still want the interceptor approach, you need to check if the transaction has been marked for rollback back, then you need to join the transaction with EM.join and from there you attempt to close and discard the joined transaction before starting another one to invoke the retry operation on. Bear in mind that you only do the rety when the transaction was marked for roll back because of that specific exception. Needless to say that this doesn't seem to be a clean way to handle your transactions (if you can get it to work that is).