SET storage_system_stack_trace_pipe_read_timeout_ms = 1000; -- { echo } SELECT count() > 0 FROM system.stack_trace WHERE query_id != ''; -- opimization for not reading /proc/self/task/{}/comm and avoid sending signal SELECT countIf(thread_id > 0) > 0 FROM system.stack_trace; -- optimization for trace SELECT count(trace) > 0 FROM system.stack_trace WHERE length(trace) > 0 LIMIT 1; -- optimization for query_id SELECT length(query_id) > 0 FROM system.stack_trace WHERE query_id != '' LIMIT 1; -- optimization for thread_name SELECT length(thread_name) > 0 FROM system.stack_trace WHERE thread_name != '' LIMIT 1; -- enough rows (optimizations works "correctly") SELECT count() > 100 FROM system.stack_trace;