MySQL useful add-on collection using UDF

I really like this new toy called UDF. So I try to provide some more, hopefully useful, functionality.

A list of what I have done up to now you can find here:

• Query and change InnoDB spin_wait_delay: udf_spin_wait_delay-5.1.30-linux-i686-glibc23.so (md5 807c6bc09b5dc88a8005788519f2483a)
• Send message to the MySQL error log: udf_log_error-5.1.30-linux-i686-glibc23.so (md5 dc8ef3e91cf6dec84ab3ad95626ec9b5)
• ...

If you have some more suggestions, please let me know.

Get and set InnoDB spin_wait_delay

mysql> CREATE FUNCTION spin_wait_delay RETURNS INTEGER SONAME "udf_spin_wait_delay-5.1.30-linux-i686-glibc23.so";

mysql> SELECT spin_wait_delay();
+--------------------+
| spin_wait_delay(5) |
+--------------------+
|                  5 |
+--------------------+

mysql> SELECT spin_wait_delay(8);
+--------------------+
| spin_wait_delay(8) |
+--------------------+
|                  8 |
+--------------------+

mysql> DROP FUNCTION spin_wait_delay;

Send message to MySQL error log

mysql> CREATE FUNCTION log_error RETURNS INTEGER SONAME "udf_log_error-5.1.30-linux-i686-glibc23.so";

mysql> SELECT log_error('My error message...');

shell> tail -n 1 error.log
091019 20:11:07 My error message...

mysql> DROP FUNCTION log_error;