[seam-dev] Re: Blocked threads

[Christian Bauer]

I was able to double my throughput and halve the average response time  
in my load test by fixing the following JNDI UserTransaction lookups  
(which are all blocking on the hashtable):

- Removing the ManagedEntityIdentityInterceptor from the default  
interceptor stack.

- Removing the TransactionInterceptor which is used with  
@Transactional by the EntityHome/Home/Query components (I don't use  
it) - and I also question why it is used on EntityConverter/ 
EntityLoader. Especially for the converter/loaders this is never  
necessary, they are always called inside a JSF request that is wrapped  
by Seam in transactions and saying "Transaction required" again and  
again is just costing a JNDI lookup.

- Removing the joinTransaction() that is triggered on every  
EntityHome.getInstance(). EntityQuery and EntityIdentity do the same.  
This also doesn't seem to be necessary, at least not for Seams  
ManagedPersistenceContext which enlists the EM with the transaction on  
@Unwrap (and it has a condition that avoids double-joins - hence only  
one UT JNDI lookup per request).

All of this needs more testing, this is just some quick hack.  
Basically, try to find the guys who call Transaction.instance() more  
than once (or twice) during a request.