GC time metrics should be total time. (#3216)

* GC time metrics should be total time.

* Add it to change log.

* FYI @hanamily you missed to change this in self observability.

CHANGES.md

@@ -52,6 +52,7 @@ Release Notes.
 * Totally remove `IDs can't be null` log, to avoid misleading.
 * Fix provider has been initialized repeatedly.
 * Adjust providers conflict log message.
+* Fix using wrong gc time metrics in OAL.
 
 #### UI
 * Fix refresh is not working after endpoint and instance changed.

oap-server/server-starter/src/main/resources/official_analysis.oal

@@ -77,8 +77,8 @@ instance_jvm_memory_heap = from(ServiceInstanceJVMMemory.used).filter(heapStatus
 instance_jvm_memory_noheap = from(ServiceInstanceJVMMemory.used).filter(heapStatus == false).longAvg();
 instance_jvm_memory_heap_max = from(ServiceInstanceJVMMemory.max).filter(heapStatus == true).longAvg();
 instance_jvm_memory_noheap_max = from(ServiceInstanceJVMMemory.max).filter(heapStatus == false).longAvg();
-instance_jvm_young_gc_time = from(ServiceInstanceJVMGC.time).filter(phrase == GCPhrase.NEW).longAvg();
-instance_jvm_old_gc_time = from(ServiceInstanceJVMGC.time).filter(phrase == GCPhrase.OLD).longAvg();
+instance_jvm_young_gc_time = from(ServiceInstanceJVMGC.time).filter(phrase == GCPhrase.NEW).sum();
+instance_jvm_old_gc_time = from(ServiceInstanceJVMGC.time).filter(phrase == GCPhrase.OLD).sum();
 instance_jvm_young_gc_count = from(ServiceInstanceJVMGC.count).filter(phrase == GCPhrase.NEW).sum();
 instance_jvm_old_gc_count = from(ServiceInstanceJVMGC.count).filter(phrase == GCPhrase.OLD).sum();
 

oap-server/server-telemetry/telemetry-prometheus/src/main/java/org/apache/skywalking/oap/server/telemetry/prometheus/PrometheusTelemetryProvider.java

@@ -23,7 +23,9 @@ import io.prometheus.client.hotspot.*;
 import java.io.IOException;
 import org.apache.skywalking.oap.server.library.module.*;
 import org.apache.skywalking.oap.server.telemetry.TelemetryModule;
+import org.apache.skywalking.oap.server.telemetry.api.MetricsCollector;
 import org.apache.skywalking.oap.server.telemetry.api.MetricsCreator;
+import org.apache.skywalking.oap.server.telemetry.none.MetricsCollectorNoop;
 
 /**
  * Start the Prometheus
@@ -51,6 +53,7 @@ public class PrometheusTelemetryProvider extends ModuleProvider {
 
     @Override public void prepare() throws ServiceNotProvidedException, ModuleStartException {
         this.registerServiceImplementation(MetricsCreator.class, new PrometheusMetricsCreator());
+        this.registerServiceImplementation(MetricsCollector.class, new MetricsCollectorNoop());
         try {
             new HTTPServer(config.getHost(), config.getPort());
         } catch (IOException e) {