Incorrect exec time for child spans when using completable future in spring controller #7825
Description
Hi,
When diagnosing some performance issues, I noticed that the execution times for child spans in traces are incorrect for APIs that are implemented using Spring Async controller feature with Completable futures.
Here is a sample trace:
Take S3.HeadBucket child span for example - the waterfall view clearly shows that the exec time is 223ms. However, in the span summary we see that exec time is reported as 111ms (exactly half).
Below is a sample code to show how we use the Completable futures:
@GetMapping("/my-service-path")
public CompletableFuture<ResponseEntity<MyResponseObject>> getSomeInfo() {
return CompletableFuture.supplyAsync(
TracedSupplier.from(() -> {
//internalServicelogic
}),
executorService
);
}
Annoyances:
We extensively use Completable futures in spring controller for all our java services. Given this issue, the time spent charts incorrectly represent the time spent in the service v/s the downstream components. This defeats the purpose of using APM tracing to a large extent for us.