Fix: relayd: live: data is missing between viewer attach and retry

[lttng-tools.git] / src / bin / lttng-relayd / live.c

diff --git a/src/bin/lttng-relayd/live.c b/src/bin/lttng-relayd/live.c
index 7d6dc1bc20a03a5af6cafe1e5ef170be1b7f5cb8..7bec6a6805a5ea0c65b9ba4d7c72883ad045bf46 100644 (file)
--- a/src/bin/lttng-relayd/live.c
+++ b/src/bin/lttng-relayd/live.c
@@ -1140,10 +1140,19 @@ int viewer_get_new_streams(struct relay_connection *conn)
                goto send_reply;
        }
 
+       /*
+        * For any new stream, create it with LTTNG_VIEWER_SEEK_BEGINNING since
+        * that at this point the client is already attached to the session.Aany
+        * initial stream will have been created with the seek type at attach
+        * time (for now most readers use the LTTNG_VIEWER_SEEK_LAST on attach).
+        * Otherwise any event happening in a new stream between the attach and
+        * a call to viewer_get_new_streams will be "lost" (never received) from
+        * the viewer's point of view.
+        */
        pthread_mutex_lock(&session->lock);
        ret = make_viewer_streams(session,
                        conn->viewer_session,
-                       LTTNG_VIEWER_SEEK_LAST, &nb_total, &nb_unsent,
+                       LTTNG_VIEWER_SEEK_BEGINNING, &nb_total, &nb_unsent,
                        &nb_created, &closed);
        if (ret < 0) {
                goto error_unlock_session;