--- a/src/jdk.jfr/share/classes/jdk/jfr/internal/RequestEngine.java	Wed Oct 30 16:14:56 2019 +0100
+++ b/src/jdk.jfr/share/classes/jdk/jfr/internal/RequestEngine.java	Wed Oct 30 19:43:52 2019 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -30,6 +30,7 @@
 import java.security.PrivilegedAction;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Objects;
 import java.util.concurrent.CopyOnWriteArrayList;
@@ -96,6 +97,8 @@
 
     private final static List<RequestHook> entries = new CopyOnWriteArrayList<>();
     private static long lastTimeMillis;
+    private static long flushInterval = Long.MAX_VALUE;
+    private static long streamDelta;
 
     public static void addHook(AccessControlContext acc, PlatformEventType type, Runnable hook) {
         Objects.requireNonNull(acc);
@@ -209,7 +212,9 @@
             lastTimeMillis = now;
             return 0;
         }
-        for (RequestHook he : entries) {
+        Iterator<RequestHook> hookIterator = entries.iterator();
+        while(hookIterator.hasNext()) {
+            RequestHook he = hookIterator.next();
             long left = 0;
             PlatformEventType es = he.type;
             // Not enabled, skip.
@@ -228,7 +233,6 @@
                 // for wait > period
                 r_delta = 0;
                 he.execute();
-                ;
             }
 
             // calculate time left
@@ -250,7 +254,39 @@
                 min = left;
             }
         }
+        // Flush should happen after all periodic events has been emitted
+        // Repeat of the above algorithm, but using the stream interval.
+        if (flushInterval != Long.MAX_VALUE) {
+            long r_period = flushInterval;
+            long r_delta = streamDelta;
+            r_delta += delta;
+            if (r_delta >= r_period) {
+                r_delta = 0;
+                MetadataRepository.getInstance().flush();
+                Utils.notifyFlush();
+            }
+            long left = (r_period - r_delta);
+            if (left < 0) {
+                left = 0;
+            }
+            streamDelta = r_delta;
+            if (min == 0 || left < min) {
+                min = left;
+            }
+        }
+
         lastTimeMillis = now;
         return min;
     }
+
+    static void setFlushInterval(long millis) {
+        // Don't accept shorter interval than 1 s.
+        long interval = millis < 1000 ? 1000  : millis;
+        flushInterval = interval;
+        if (interval < flushInterval) {
+            synchronized (JVM.FILE_DELTA_CHANGE) {
+                JVM.FILE_DELTA_CHANGE.notifyAll();
+            }
+        }
+    }
 }