Retained heap is 0 for all threads?

[ldorigo]

I captured a snapshot of large production backend app running under uvicorn (in a cloud container) and am trying to analyze it on my own machine. Both the web ui and the cli analyzer show 0 retained heap for every thread:

Retained heap for threads:
Thread                                             | Retained heap size
-----------------------------------------------------------------------
MainThread                                         |                  0
Thread-1 (tracing_control_thread_func)             |                  0
ThreadPoolExecutor-0_0                             |                  0
pymongo_server_monitor_thread                      |                  0
pymongo_server_monitor_thread                      |                  0
pymongo_server_monitor_thread                      |                  0
pymongo_kill_cursors_thread                        |                  0
pymongo_server_rtt_thread                          |                  0
pymongo_server_rtt_thread                          |                  0
pymongo_server_rtt_thread                          |                  0
sentry.monitor                                     |                  0
pymongo_server_monitor_thread                      |                  0
pymongo_server_monitor_thread                      |                  0
pymongo_server_monitor_thread                      |                  0
pymongo_kill_cursors_thread                        |                  0
pymongo_server_rtt_thread                          |                  0
pymongo_server_rtt_thread                          |                  0
pymongo_server_rtt_thread                          |                  0
ThreadPoolExecutor-3_0                             |                  0
sentry-sdk.BackgroundWorker                        |                  0
ThreadPoolExecutor-0_1                             |                  0
ThreadPoolExecutor-0_2                             |                  0
ThreadPoolExecutor-3_1                             |                  0
ThreadPoolExecutor-3_2                             |                  0
ThreadPoolExecutor-3_3                             |                  0
ThreadPoolExecutor-3_4                             |                  0
ThreadPoolExecutor-0_3                             |                  0
ThreadPoolExecutor-0_4                             |                  0
ThreadPoolExecutor-0_5                             |                  0
ThreadPoolExecutor-3_5                             |                  0
ThreadPoolExecutor-0_6                             |                  0
pymongo_server_monitor_thread                      |                  0
pymongo_server_monitor_thread                      |                  0
pymongo_server_monitor_thread                      |                  0
pymongo_kill_cursors_thread                        |                  0
pymongo_server_rtt_thread                          |                  0
pymongo_server_rtt_thread                          |                  0
pymongo_server_rtt_thread                          |                  0
ThreadPoolExecutor-0_7                             |                  0
sentry.profiler.ThreadScheduler                    |                  0
ThreadPoolExecutor-0_8                             |                  0
ThreadPoolExecutor-0_9                             |                  0
Thread-2 (tracing_control_thread_func)             |                  0
AnyIO worker thread                                |                  0

Additionally, when I click on the "heap" tab in the web ui; nothing happens.

Any idea what might be wrong? I'm running the version from the current main branch.