Re: [eclipselink-dev] Question about performance issue withSeqencingMana

["Andrei Ilitchev" <andrei.ilitchev@xxxxxxxxxx>]

Mitesh,

The best solution is to use sequencing connection pool - that's possible in 
case you use nonjtaDataSource (which used always to be the case with 
GlassFish?).
There's https://bugs.eclipse.org/bugs/show_bug.cgi?id=220402 describing the 
issue, the fix and the workaround.

Thanks,

Andrei
----- Original Message ----- 
From: "Mitesh Meswani" <Mitesh.Meswani@xxxxxxx>
To: <eclipselink-dev@xxxxxxxxxxx>
Sent: Thursday, March 26, 2009 9:09 PM
Subject: [eclipselink-dev] Question about performance issue 
withSeqencingManager


> Hi,
>
> We seem to have a performance issue with Table Sequences while running 
> inside container ( => external transaction controller). If multiple 
> threads try to do getNextValue() on a table sequence and our preallocation 
> bucket is empty and external transaction controller is used, all of them 
> can reach the code at line 468 of 
> SequencingManager.Preallocation_Transaction_NoAccessor_State.getNextValue() 
> which calls sequence.getGeneratedVector(...) . This would result in all of 
> them issuing an update statement to the sequence table and being blocked 
> out by database till preceding threads' transaction commits. The code of 
> Preallocation_Transaction_NoAccessor_State.getNextValue() is explicitly 
> written to not obtain locks around sequence.getGeneratedVector(...) if 
> running with external transaction controller. There is fair amount of 
> comment written but some how I am still not able to figure out why we are 
> not obtaining locks for this case. Can some one familiar with history of 
> the code comment on this.
>
> Thanks,
> Mitesh
>
> _______________________________________________
> eclipselink-dev mailing list
> eclipselink-dev@xxxxxxxxxxx
> https://dev.eclipse.org/mailman/listinfo/eclipselink-dev