mysql database online to troubleshoot problems, often used show processlist and show full processlist two commands
The output processlist command shows which threads are running, not only can view all of the current number of connections, you can also view the current connection status to help identify problematic queries and so on.
If the root account, you can see all currently connected users. If other common account, you can only see their occupancy connection. showprocesslist only lists the current 100. If you want to list all, you can use SHOW FULL PROCESSLIST command
The meaning of each column:
1, id column, when the user logs mysql, the system assigns the "connection_id", The connection_id can use the function () View
2, user column shows the current user. If not root, this command will only display the user purview sql statement
3, host column, this statement is displayed from which ip port on which the hair can be used to track user problems arise statement
4, db column, show this which process is currently connected to a database
5, command column, the underlying command for the current connection, the general value of dormant (sleep), query (query), connect (connect), etc.
6, time column, this status display duration in seconds
7, state columns show the use of the sql statement for the current connection status, it is important columns. state describes a state statement execution. A sql statement to query, for example, may need to go through copying to tmp table, sorting result, sending data and other state before they can complete
8, info columns show the sql statement is an important basis for judging the problem statement, the general record is statement thread of execution. The default display only the first 100 characters, that is, you see the statement may be truncated, and look at all the information, use show full processlist.
Remarks:
1, according to an IP packet client to view the number of links each client's situation
select
client_ip,
count
(client_ip)
as
client_num
from
(
select
substring_index(host,
':'
,1)
as
client_ip
from
information_schema.processlist )
as
connect_info
group
by
client_ip
order
by
client_num
desc
;
select
*
from
information_schema.processlist
where
Command !=
'Sleep'
order
by
Time
desc
;
select
concat(
'kill '
, id,
';'
)
from
information_schema.processlist
where
Command !=
'Sleep'
and
Time
> 60
order
by
Time
desc
;