cond_instances table lists
all the conditions seen by the Performance Schema while the
server executes. A condition is a synchronization mechanism
used in the code to signal that a specific event has happened,
so that a thread waiting for this condition can resume work.
When a thread is waiting for something to happen, the condition name is an indication of what the thread is waiting for, but there is no immediate way to tell which other threads cause the condition to happen.
cond_instances table has
The instrument name associated with the condition.
The address in memory of the instrumented condition.
TRUNCATE TABLE is not permitted