MySQL 5.7 Reference Manual Including MySQL NDB Cluster 7.5 and NDB Cluster 7.6
These views summarize I/O consumers to display time waiting for I/O, grouped by thread. By default, rows are sorted by descending total I/O latency.
The io_by_thread_by_latency and
x$io_by_thread_by_latency views
have these columns:
user
For foreground threads, the account associated with the thread. For background threads, the thread name.
total
The total number of I/O events for the thread.
total_latency
The total wait time of timed I/O events for the thread.
min_latency
The minimum single wait time of timed I/O events for the thread.
avg_latency
The average wait time per timed I/O event for the thread.
max_latency
The maximum single wait time of timed I/O events for the thread.
thread_id
The thread ID.
processlist_id
For foreground threads, the processlist ID of the thread.
For background threads, NULL.