How can I stop a running MySQL query?

Question

I connect to mysql from my Linux shell. Every now and then I run a SELECT query that is too big. It prints and prints and I already know this is no

Answer 1

The author of this question mentions that it’s usually only after MySQL prints its output that he realises that the wrong query was executed. As noted, in this case, Ctrl-C doesn’t help. However, I’ve noticed that it will abort the current query – if you catch it before any output is printed. For example:

mysql> select * from jos_users, jos_comprofiler;

MySQL gets busy generating the Cartesian Product of the above two tables and you soon notice that MySQL hasn't printed any output to screen (the process state is Sending data) so you type Ctrl-C:

Ctrl-C -- sending "KILL QUERY 113240" to server ...
Ctrl-C -- query aborted.
ERROR 1317 (70100): Query execution was interrupted

Ctrl-C can similarly be used to stop an UPDATE query.