Merge pull request #16940 from vespa-engine/balder/do-not-append-empty-trace-messages

Balder/do not append empty trace messages

1 files changed, 5 insertions, 1 deletions

diff --git a/documentapi/src/main/java/com/yahoo/documentapi/messagebus/MessageBusVisitorSession.java b/documentapi/src/main/java/com/yahoo/documentapi/messagebus/MessageBusVisitorSession.java
index 675f20e3807..88ef67e1854 100755
--- a/documentapi/src/main/java/com/yahoo/documentapi/messagebus/MessageBusVisitorSession.java
+++ b/documentapi/src/main/java/com/yahoo/documentapi/messagebus/MessageBusVisitorSession.java
@@ -1036,7 +1036,11 @@ public class MessageBusVisitorSession implements VisitorSession {
         params.getControlHandler().onProgress(progress.getToken());
         statistics.add(reply.getVisitorStatistics());
         params.getControlHandler().onVisitorStatistics(statistics);
-        trace.getRoot().addChild(reply.getTrace().getRoot());
+        // A visitor session might be long lived so we need a safeguard against blowing the memory if tracing
+        // has been enabled.
+        if ( ! reply.getTrace().getRoot().isEmpty() && (trace.getRoot().getNumChildren() < 1000)) {
+            trace.getRoot().addChild(reply.getTrace().getRoot());
+        }
 
         if (params.getDynamicallyIncreaseMaxBucketsPerVisitor()
                 && (reply.getVisitorStatistics().getDocumentsReturned()