There is no way to set the tracing threshold time for queries or search from the connection string. If you call cntl programmatically, it works fine. The issue is super simple to fix:

from src/cntl.cc:

So – we have 2 tracing_threshold_search, and no tracing_threshold_query. And of course the search actually sets the query (the second one is never hit), so neither really works from the connection string.

I'll make a simple patch for this. Python tests will skip this one until this goes in - ideally in 3.0.2.