Threading on ticker mode · graphql-java/java-dataloader · Discussion #256

Hello all,

We have been using ticker mode for awhile now and are moving away from it due to a troubling amount of threads spawned / cpu / gc overload.

We currently have 47 DLs in production using a dispatch all basic predicate and looking at the code

See that dispatches are scheduled on a per DL level rather than a dispatch all, if i am doing calculations correctly then I believe a tick time of 5 ms , with 47 DLs, and a call time of 400ms == 3760 threads per call.

There is room for tuning here but I was wondering why we need a per dataloader dispatch vs, a single callback which runs a dispatchAll on a single thread for the reschedule. This seems like it would significantly decrease thread overhead for the ticker mode.

Beyond this we are moving towards a more deterministic, level by level deterministic dispatch which i have been thinking about how to contribute back to OS but haven't found a great way to generalize it yet.

Wondering about thoughts specifically on if a per DL reschedule is necessary vs a dispatch all at once when the default dispatch all predicate is used.

Thanks!