MySQL 5.7 Reference Manual Including MySQL NDB Cluster 7.5 and NDB Cluster 7.6
These views summarize statement activity, file I/O, and connections, grouped by host.
The host_summary and
x$host_summary views have these
columns:
host
The host from which the client connected. Rows for which
the HOST 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.
statements
The total number of statements for the host.
statement_latency
The total wait time of timed statements for the host.
statement_avg_latency
The average wait time per timed statement for the host.
table_scans
The total number of table scans for the host.
file_ios
The total number of file I/O events for the host.
file_io_latency
The total wait time of timed file I/O events for the host.
current_connections
The current number of connections for the host.
total_connections
The total number of connections for the host.
unique_users
The number of distinct users for the host.
current_memory
The current amount of allocated memory for the host.
total_memory_allocated
The total amount of allocated memory for the host.