On 26/09/2025 10:36, Jianbin Chen wrote:
Hi everyone,
I hope you’re doing well. I have a question about a multi-tenant
scenario. I want to create a dedicated thread pool for each tenant,
and these pools will perform a lot of I/O (for example, database reads
and writes). For this reason I’d like to use virtual threads. However,
because virtual threads share platform threads under the hood, they
cannot be fully isolated from one another.
Can you say a bit more about the multi-tenancy implementation? Is this a
fork of the JDK with deep changes to isolate tenants, or is this
isolation built with module layers or class loaders? If the latter then
I assume it's an issue for the FJP common pool and all other system-wide
resources.
So while the JDK doesn't have any support for tenancies, there is
prototype/experimental support for custom schedulers in the loom repo
[1]. That could be used to experiment with a having a virtual thread
scheduler per tenant, or using a system-wide scheduler that dispatches
the tasks for virtual threads in a tenant to the carriers in that
tenant. It could be fun to work on. If you do explore this area then
please come back with any results.
-Alan
[1]
https://github.com/openjdk/loom/blob/fibers/loom-docs/CustomSchedulers.md
