ThreadLocals in Virtual Threads

[Ron Pressler]

You can try using an ArrayBlockingQueue<Connection> as such a blocking pool. 

— Ron


On 4 January 2021 at 20:38:00, Swaranga Sarma (sarma.swaranga at gmail.com) wrote:

You are correct that the tests don't need a TL per se but we were using it  
and along with a fixed size ThreadPool for the tests, we got a cheap way to  
achieve a "connection pool" functionality. With virtual threads, we will  
need a proper pool of some sort. Thank you.  

Regards  
Swaranga  


On Mon, Jan 4, 2021 at 11:57 AM Alan Bateman <Alan.Bateman at oracle.com>  
wrote:  

> On 04/01/2021 19:25, Swaranga Sarma wrote:  
> > :  
> >  
> > With the current Executor services and behavior of ThreadLocals, I know  
> > that I will never create more than X concurrent connections (where X is  
> the  
> > size of the executor service) even if I have thousands of tests in my  
> suite.  
> >  
> > Are there any plans of "processor" local or "carrier thread" local?  
> >  
> I assume this test doesn't really need a TL, instead it's just a cache  
> of DB connections. It could acquire in the setup and return it to the  
> cache and/or close it in the teardown method. If you've got too many  
> tests executing in parallel then they can block in acquire until there  
> is a DB connection or permit available.  
>  
> SoL-part2 [1] has a summary on the Processor Locals topic. Early  
> exploration built on the Linux restartable sequences facility but it's  
> been set aside from now. It's probably too low level for the cache of DB  
> connections.  
>  
> -Alan  
>  
>  
> [1]  
>  
> https://cr.openjdk.java.net/~rpressler/loom/loom/sol1_part2.html#processor-locals  
>  
>  
>