boompty boomp

If you want to duplicate a MySQL table (with data), you can do:

mysql> CREATE TABLE tmpscores LIKE scores;
Query OK, 0 rows affected (0.00 sec)
 
mysql> INSERT INTO tmpscores SELECT * from scores;
Query OK, 116 rows affected (0.02 sec)
Records: 116  Duplicates: 0  Warnings: 0
 
mysql>

Alternatively, you can do this in one step:

mysql> CREATE TABLE tmpscores SELECT * FROM scores;
Query OK, 116 rows affected (0.02 sec)
Records: 116  Duplicates: 0  Warnings: 0
 
mysql>

Note that the first method does create indexes for you while the second doesn’t (see here).

Usually, I update variables on the fly using something like:

mysql> SET GLOBAL max_connections = 150;

… and then modify /etc/my.cnf to make the change persistent.

The problem in doing this is that you’re not verifying that your /etc/my.cnf is correct and can only hope that a restart doesn’t encounter any problems.

Fortunately, Sai emailed us a great little tip to verify the syntax. You can run the following which will report errors in /etc/my.cnf:

# /usr/libexec/mysqld --help --verbose
081009  9:55:36 [ERROR] /usr/libexec/mysqld: unknown variable 'mmax_connections=150'
 
#

Perfect. Just what the doctor ordered.