How to get a list of hosts connected to a mysql server - c++

Question

I am trying to get a list of hosts connected to a mysql server. How can i get this?
What should i do after connecting to the mysql server.
Code snippets will really help.
Also whats the best api to use to connect to mysql using c++?

Answer 1

One way you could do it is to execute the query show processlist, which will give you a table with Id, User, Host, db, Command, Time, State and Info columns. Remember that your show processlist query will be part of the output.

Answer 2

You can try this query: select distinct host from information_schema.processlist;
For example, there are multiple connections from 10.9.0.10 and one local connection.
mysql> select distinct host from information_schema.processlist;
+-----------------+
| host |
+-----------------+
| 10.9.0.10:63668 |
| 10.9.0.10:63670 |
| 10.9.0.10:63664 |
| 10.9.0.10:63663 |
| 10.9.0.10:63666 |
| 10.9.0.10:63672 |
| 10.9.0.10:63665 |
| 10.9.0.10:63671 |
| 10.9.0.10:63669 |
| 10.9.0.10:63667 |
| localhost |
| |
+-----------------+
12 rows in set (0,00 sec)
If you want only hosts (not different connections), you can try something like this: select distinct substring_index(host,':',1) from information_schema.processlist;
Example:
mysql> select distinct substring_index(host,':',1) from information_schema.processlist;
+-----------------------------+
| substring_index(host,':',1) |
+-----------------------------+
| 10.9.0.10 |
| localhost |
| |
+-----------------------------+
3 rows in set (0,00 sec)
You can see, that MySQL shows me one empty row, it is normal (i have a deamon process):
mysql> select distinct substring_index(host,':',1),`command` from information_schema.processlist;
+-----------------------------+---------+
| substring_index(host,':',1) | command |
+-----------------------------+---------+
| 10.9.0.10 | Sleep |
| localhost | Query |
| | Daemon |
+-----------------------------+---------+
You can remove it with where `command`!="Daemon" or where `host`!=''
And here is good link with query which also count connections from host and show which users are connected: http://blog.shlomoid.com/2011/08/how-to-easily-see-whos-connected-to.html