I think this sounds reasonable - make it possible to enable TX, but not by default for backwards compat.
I think this has to cover at least 80% of use cases.
On 12 Sep 2011, at 20:20, Marina Vatkina wrote:
> Thanks everybody who chimed in (and resending Adam's email that didn't make it to the EG alias)
>
> Load can be non-transactional (and it will preserve isolation levels),
> though I understand that it'd be strange to allow transactions on
> PreDestroy but on on PostConstruct. So this is not an issue. The real
> issue is the backward compatibility. We can't just break something that
> was the same way for a very long time.
>
> But we can allow to specify transactional attribute on the callback
> methods of a SFSB directly if this solves the problem.
>
> Q: Are there cases when it is not possible to do via annotations or DD?
>
> thanks,
> -marina
>
>
> Adam Bien wrote:
>> Hi Marina,
>>
>> if you are accessing a EntityManager you will need to start a transaction. Usually you also would like to access the DB in a TX to have consistent reads and rely on defined isolation level settings.
>> @PreDestroy is even more crucial. It could be used to flush the cache to a DB.
>>
>> I use sometimes Singletons in single node clusters for deferred writes.
>>
>> thanks!,
>>
>> adam
>>
>>
>>
>> On 10.09.2011, at 02:45, Marina Vatkina wrote:
>>
>>
>>> Adam,
>>>
>>> Can you describe the issue in more details? When will pre-fetching data in Singleton's PostConstuct would need to be transactional?
>>>
>>> thanks,
>>> -marina
>>>
>>> Adam Bien wrote:
>>>
>>>> +1 for transactional callbacks. Had the issue in @Singletons, which prefetched the data from DB already.
>>>> On 07.09.2011, at 14:40, Pete Muir wrote:
>>>>
>>>>
>>>>> In general, it's very useful for a postconstruct/predestroy method to be able to be called within a transaction.
>>>>>
>>>>> For example, consider seeding data into a database (singleton with @Startup and an @PreDestroy), logging user access (http session scoped SFSB) and so on.
>>>>>
>>>>> On 7 Sep 2011, at 03:18, Marina Vatkina wrote:
>>>>>
>>>>>
>>>>>> Experts,
>>>>>>
>>>>>> Let's clarify transactional support for PostConstuct or PreDestroy methods.
>>>>>>
>>>>>> a) PostConstuct or PreDestroy methods of a singleton session bean can be executed in a transaction, while other bean types do not seem to allow this. Why would the singleton bean is different from any other bean?
>>>>>>
>>>>>> b) Why would the transactional attribute be specified differently for a singleton vs. other beans? See e.g. an XXX marker under section "8.3.7 Specification of the Transaction Attributes for a Bean’s Methods" in one of the bullets of the "Transaction attributes are specified for the following methods:" text:
>>>>>>
>>>>>> <...>
>>>>>>
>>>>>> For a singleton session bean, the transaction attributes are specified for the PostConstruct and PreDestroy lifecycle callback interceptor methods, if any. In order to specify the transaction attribute for a PostConstuct or PreDestroy method of a singleton session bean, the transaction attribute must be specified for the method(s) on the bean class, rather than for a superclass or PostConstruct or PreDestroy interceptor method."
>>>>>>
>>>>>> thanks,
>>>>>> -marina
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>
>>
>>
>>
>