As of MySQL 5.6.3, the Performance Schema instruments stages,
which are steps during the statement-execution process, such as
parsing a statement, opening a table, or performing a
filesort operation. Stages correspond to the
thread states displayed by SHOW
PROCESSLIST or that are visible in the
INFORMATION_SCHEMA.PROCESSLIST
table. Stages begin and end when state values change.
Within the event hierarchy, wait events nest within stage events, which nest within statement events.
These tables store stage events:
events_stages_current: Current
stage events
events_stages_history: The most
recent stage events for each thread
events_stages_history_long: The
most recent stage events overall