These views summarize file I/O, grouped by user and event type. By default, rows are sorted by user and descending total latency.
The user_summary_by_file_io_type and x$user_summary_by_file_io_type views have these columns:
user
The client user name. Rows for which the USER column in the underlying Performance Schema table is NULL are assumed to be for background threads and are reported with a host name of background.
event_name
The file I/O event name.
total
The total number of occurrences of the file I/O event for the user.
latency
The total wait time of timed occurrences of the file I/O event for the user.
max_latency
The maximum single wait time of timed occurrences of the file I/O event for the user.