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 27.12.20.1, “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. 

The socket summary tables have these indexes: 

• socket_summary_by_event_name : 

•Primary key on ( EVENT_NAME ) 

• socket_summary_by_instance : 

•Primary key on ( OBJECT_INSTANCE_BEGIN ) 

•Index on ( EVENT_NAME ) 

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. 

## 27.12.20.10 Memory Summary Tables 

The Performance Schema instruments memory usage and aggregates memory usage statistics, detailed by these factors: 

