MySQL 5.6 Reference Manual Including MySQL NDB Cluster 7.3-7.4 Reference Guide
The Performance Schema maintains socket summary tables, which aggregate timer and byte count information for socket operations:
socket_summary_by_event_name
:
Aggregate timer and byte count statistics generated by the
wait/io/socket/*
instruments for all
socket I/O operations, per socket instrument.
socket_summary_by_instance
:
Aggregate timer and byte count statistics generated by the
wait/io/socket/*
instruments for all
socket I/O operations, per socket instance. When a
connection terminates, the row in
socket_summary_by_instance
corresponding to it is deleted.
The socket summary tables do not aggregate waits generated by
idle
events while sockets are waiting for
the next request from the client. For idle
event aggregations, use the wait-event summary tables; see
Section 22.12.9.1, “Wait Event Summary Tables”.
Each socket summary table has one or more grouping columns to
indicate how the table aggregates events. Event names refer to
names of event instruments in the
setup_instruments
table:
socket_summary_by_event_name
has an EVENT_NAME
column. Each row
summarizes events for a given event name.
socket_summary_by_instance
has an OBJECT_INSTANCE_BEGIN
column.
Each row summarizes events for a given object.
Each socket summary table has these summary columns containing aggregated values:
COUNT_STAR
,
SUM_TIMER_WAIT
,
MIN_TIMER_WAIT
,
AVG_TIMER_WAIT
,
MAX_TIMER_WAIT
These columns aggregate all operations.
COUNT_READ
,
SUM_TIMER_READ
,
MIN_TIMER_READ
,
AVG_TIMER_READ
,
MAX_TIMER_READ
,
SUM_NUMBER_OF_BYTES_READ
These columns aggregate all receive operations
(RECV
, RECVFROM
, and
RECVMSG
).
COUNT_WRITE
,
SUM_TIMER_WRITE
,
MIN_TIMER_WRITE
,
AVG_TIMER_WRITE
,
MAX_TIMER_WRITE
,
SUM_NUMBER_OF_BYTES_WRITE
These columns aggregate all send operations
(SEND
, SENDTO
, and
SENDMSG
).
COUNT_MISC
,
SUM_TIMER_MISC
,
MIN_TIMER_MISC
,
AVG_TIMER_MISC
,
MAX_TIMER_MISC
These columns aggregate all other socket operations, such
as CONNECT
, LISTEN
,
ACCEPT
, CLOSE
, and
SHUTDOWN
. There are no byte counts for
these operations.
The socket_summary_by_instance
table also has an EVENT_NAME
column that
indicates the class of the socket:
client_connection
,
server_tcpip_socket
,
server_unix_socket
. This column can be
grouped on to isolate, for example, client activity from that
of the server listening sockets.
TRUNCATE TABLE
is permitted for
socket summary tables. Except for
events_statements_summary_by_digest
,
tt resets the summary columns to zero rather than removing
rows.