TracerProvider shutdown release resources

CHANGELOG.md

@@ -24,6 +24,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Add `Producer` interface and `Reader.RegisterProducer(Producer)` to `go.opentelemetry.io/otel/sdk/metric` to enable external metric Producers. (#3524)
 - Add `NewMetricProducer` to `go.opentelemetry.io/otel/bridge/opencensus`, which can be used to pass OpenCensus metrics to an OpenTelemetry Reader. (#3541)
 - Global logger uses an atomic value instead of a mutex. (#3545)
+- Document TracerProvider Shutdown releasing resources. (#3551)
 
 ### Deprecated
 

sdk/trace/provider.go

@@ -227,7 +227,8 @@ func (p *TracerProvider) ForceFlush(ctx context.Context) error {
 	return nil
 }
 
-// Shutdown shuts down the span processors in the order they were registered.
+// Shutdown shuts down TracerProvider. All registered span processors are shut down
+// in the order they were registered and any held computational resources are released.
 func (p *TracerProvider) Shutdown(ctx context.Context) error {
 	spss := p.spanProcessors.Load().(spanProcessorStates)
 	if len(spss) == 0 {
@@ -255,6 +256,7 @@ func (p *TracerProvider) Shutdown(ctx context.Context) error {
 			}
 		}
 	}
+	p.spanProcessors.Store(spanProcessorStates{})
 	return retErr
 }