==== Investigating mysql ====
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== Query List ==
To view mysql query list run the following command from the command line:
<sxh bash>
SELECT * FROM information_schema.processlist WHERE command != 'Sleep' ORDER BY time;
</sxh>

\\

<sxh bash>
mysqladmin pr | grep Query | sort -nk12
</sxh>
Example output:
<sxh bash>
| 5950 | user1      | localhost | example_com | Query   | 0    | checking query cache for query | SELECT m.filename, m.datedir, m.description, m.media_type, m.preview
| 5977 | root          | localhost |               | Query   | 0    |                                | show processlist                                                                                     |
| 5032 | user2 | localhost | new_shop | Query   | 49   | Sending data                   | SELECT m.*, mm.is_winner, (SELECT COUNT(*) FROM votes v WHERE month = '8' AND v.season = '0' AND v.m |
</sxh>
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== All Processes ==
If you need to investigate mysql you can troubleshoot by investigating the processlist
<sxh>
show processlist;
</sxh>
You should see an output similar to the following:

<sxh>
+--------+---------+-----------+------+---------+-------+-------+------------------+ 
| Id     | User    | Host      | db   | Command | Time  | State | Info             | 
+--------+---------+-----------+------+---------+-------+-------+------------------+ 
| 109530 | root   | localhost | NULL | Query   |     0 | NULL  | show processlist | 
| 106092 | wp_usr | localhost | wp   | Sleep   | 25140 |       | NULL             |
| 106090 | wp_usr | localhost | wp   | Sleep   | 25140 |       | NULL             |
| 106091 | wp_usr | localhost | wp   | Sleep   | 25139 |       | NULL             |
| 109751 | root   | localhost | NULL | Sleep   |   244 |       | NULL             |
</sxh>
\\
=== Process list WITHOUT sleeping processes ===
<sxh>
SELECT * FROM information_schema.processlist WHERE command != 'Sleep' ORDER BY id;
</sxh>
\\
^ Header ^ Description ^
| ID     | Connection identifier |
| User   | MySQL user who issued the statement |
| Host   | Host name of the client issuing the statement |
| db     | Default database, if one is selected, otherwise NULL |
| Command| The type of command the thread is executing |
| Time   | Time in seconds that the thread has been in its current state |
| State  | An action, event, or state that indicates what the thread is doing |
| Info   | The statement the thread is executing |


=== mysql Common Commands ===
^ Command     ^ Description ^
| Connect     | Replication slave is connected to its master |
| Connect Out | Replication slave is in the process of connecting to its master |
| Drop DB     | Executing an operation to drop a database |
| Error       | Error |
| Execute     | Executing a prepared statement |
| Fetch       | Fetching the results of an executed prepared statement |
| Kill        | Killing another thread |
| Query       | Executing a statement |
| Quit        | In the process of terminating the thread |
| Sleep       | Waiting for the client to send a new statement |
| Table Dump  | Sending the contents of a table to a slave |

source: https://mariadb.com/kb/en/mariadb/thread-command-values/