With administrative permissions im mysql, how can I see all the open connections to a specific db in my server?
The command is
SHOW PROCESSLIST
Unfortunately, it has no narrowing parameters. If you need them you can do it from the command line:
mysqladmin processlist | grep database-name
As well you can use:
mysql> show status like '%onn%';
+--------------------------+-------+
| Variable_name | Value |
+--------------------------+-------+
| Aborted_connects | 0 |
| Connections | 303 |
| Max_used_connections | 127 |
| Ssl_client_connects | 0 |
| Ssl_connect_renegotiates | 0 |
| Ssl_finished_connects | 0 |
| Threads_connected | 127 |
+--------------------------+-------+
7 rows in set (0.01 sec)
Feel free to use
Mysql-server-status-variables or Too-many-connections-problem
That should do the trick for the newest MySQL versions:
SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST WHERE DB like "%DBName%";
You can invoke MySQL show status command
show status like 'Conn%';
For more info read Show open database connections
SQL:
show full processlist;
This is what the MySQL Workbench does.
In MySql,the following query shall show the total number of open connections:
show status like 'Threads_connected';
If you're running a *nix system, also consider mytop.
To limit the results to one database, press "d" when it's running then type in the database name.
From the monitoring context here is how you can easily view the connections to all databases sorted by database. With that data easily monitor.
SELECT DB,USER,HOST,STATE FROM INFORMATION_SCHEMA.PROCESSLIST ORDER BY DB DESC;
+------+-------+---------------------+-----------+
| DB | USER | HOST | STATE |
+------+-------+---------------------+-----------+
| web | tommy | 201.29.120.10:41146 | executing |
+------+-------+---------------------+-----------+
If we encounter any hosts hots max connections and then not able to connect, then we can reset host tables by flushing it and is as follows:
FLUSH HOSTS;
In query browser right click on database and select processlist
Related
When I Query ProxySQL Client Connections :
select * from stats.stats_mysql_global where variable_name like 'Client_connection%';
+-------------------------------------+----------------+
| Variable_Name | Variable_Value |
+-------------------------------------+----------------+
| Client_Connections_aborted | 0 |
| Client_Connections_connected | 495 |
| Client_Connections_created | 43785 |
| Client_Connections_non_idle | 495 |
| Client_Connections_hostgroup_locked | 0 |
+-------------------------------------+----------------+
Connections non idle is always same with connections non idle;
But when I query on Process List :
show processlist;
in the command fields, all status is Sleep.
The Client_Connections_non_idle must be zero, but not in my case.
What is wrong with my thought ?
Thanks for any explanation of my problems.
I am using ProxySql v2.4.2
According to the ProxySQL documentation
Client_Connections_non_idle : number of client connections that are currently handled by the main worker threads. If ProxySQL isn’t running with “–idle-threads”, Client_Connections_non_idle is always equal to “Client_Connections_connected”
So unless you run ProxySQL with --idle-threads this is expected behaviour and nothing to worry about. You can read more about idle threads in the documentation
I already find the solution of my problem. Before i set wait_timeout too big, after I set wait_timeout into 30000 (30 second) it is normal.
I have recently started seeing high amount of set-option query count in mysql. Its around 15k/sec
mysql> SHOW GLOBAL STATUS LIKE '%set%';
+-------------------+------------+
| Variable_name | Value |
+-------------------+------------+
| Com_reset | 0 |
| Com_set_option | 5472249432 |
| Com_show_charsets | 31 |
| Com_stmt_reset | 0 |
+-------------------+------------+
4 rows in set (0.00 sec)
However nothing like "set" operation is seen in the "show processlist"
IMAGE
Any idea why?
Thanks
COM_SET_OPTION count is high probably because the MySQL library you are using issues a SET option command every time it creates a connection to the MySql server. Few libraries tend to set some basic options everytime they create a new connection.
This could also happen if your system does a lot of transactions with MySQL.
However, this is pretty normal. I am using MySql 5.6.34 with PHP. Refer
I have a thread showing in PHPmyadmin under processes. However, when I click kill, I get the error:
phpMyAdmin was unable to kill thread 148. It probably has already been closed.
Why does this thread still then show as active? How can I remove it entirely?
Open mysql client and type
mysql> show processlist;
+-----+------+-----------+------+---------+------+-------+------------------+-----------+---------------+-----------+
| Id | User | Host | db | Command | Time | State | Info | Rows_sent | Rows_examined | Rows_read |
+-----+------+-----------+------+---------+------+-------+------------------+-----------+---------------+-----------+
| 106 | root | localhost | NULL | Query | 0 | NULL | show processlist | 0 | 0 | 0 |
+-----+------+-----------+------+---------+------+-------+------------------+-----------+---------------+-----------+
1 row in set (0.00 sec)
you'll see processes with ID, than you can do this:
mysql> kill 106;
and your process (id = 106) will be killed.
Between the time that phpMyAdmin received the list of processes and the time you clicked to kill one of them, this process had finished by itself.
See also https://sourceforge.net/p/phpmyadmin/feature-requests/1490/.
This phenomenon is caused by the connection used to access PHPmyadmin itself, hence it doesn't show on the direct MySQLQuery. It can't be killed, as it would close the PHPmyadmin connection.
how to send mail alert for MySQL?
can we send alerts when the MySQL has large number of connections, or MySQL is not responding properly. Can someone help me to solve this prolem ?
You can do this in a number of ways. SHOW FULL PROCESSLIST; query would give you information about the number of connections as well as the queries being executed by each connection(thread). A sample result is as follows.
mysql> SHOW FULL PROCESSLIST;
+------+------+--------------------+------+---------+------+-------+-----------------------+
| Id | User | Host | db | Command | Time | State | Info |
+------+------+--------------------+------+---------+------+-------+-----------------------+
| 1298 | root | 192.168.1.76:37648 | NULL | Sleep | 0 | | NULL |
| 1491 | root | localhost | NULL | Query | 0 | init | show full processlist |
+------+------+--------------------+------+---------+------+-------+-----------------------+
If you are only concerned with the number of current connection(threads) you can use the following query.
mysql> SHOW STATUS WHERE `variable_name` = 'Threads_connected';
+-------------------+-------+
| Variable_name | Value |
+-------------------+-------+
| Threads_connected | 2 |
+-------------------+-------+
Now about the mail alerts, you can setup a cron job(shell script) to fire a mail alert as soon as the number of current connections exceed a certain limit. mail command can be used for this.
$ echo "Max MySQL Connections reached"| mail -s "your subject" your#email.com
Also, I came across a great MySQL Monitoring tool- MONyog. It would let you setup mail alerts for any of the MySQL variable.
My debian-based is booting so slow after I installed MySQL and imported some databases on it. Looking for some statement, I found this one during boot:
mysql> show full processlist;
+----+------------------+-----------+------+---------+------+----------------+----------------------------------------------------------------------+
| Id | User | Host | db | Command | Time | State | Info |
+----+------------------+-----------+------+---------+------+----------------+----------------------------------------------------------------------+
| 9 | debian-sys-maint | localhost | NULL | Query | 12 | Opening tables | select count(*) into #discard from `information_schema`.`PARTITIONS` |
| 10 | root | localhost | NULL | Query | 0 | NULL | show full processlist |
+----+------------------+-----------+------+---------+------+----------------+----------------------------------------------------------------------+
2 rows in set (0.00 sec)
Here the statement that causing trouble:
select count(*) into #discard from `information_schema`.`PARTITIONS`
I have +-10 databases totaling over 8gb of data.
Is there any configuration to disable this query on system booting ? If yes, why run it during boot ?
Information
I have a standard MySQL installation without custom configs.
Best regards.
It seems Debian, whose Linux Mint is based upon, have scripts that get executed when the mysql server is started or restarted, to check for corrupted tables and make an alert for that.
In my Debian server, the culprit seems to be /etc/mysql/debian-start bash script, which in turn calls /usr/share/mysql/debian-start.inc.sh , so check both scripts and comment out the function that is iterating all your tables, from a quick look it seems the following:
check_for_crashed_tables;
which is called from the debian-start script I mentioned above.