NOW() is stuck when using mysql

Question

We've been having some issues with one of our MySQL servers lately, and currently the dang thing is "stuck". For at least the last hour, NOW() is returning the same value:

mysql> select now();
+---------------------+
| now() |
+---------------------+
| 2013-06-26 02:27:14 |
+---------------------+

The system variable "timestamp" also has that same time value stored in it. How can we kick this loose so that the values are more current with real time? (it is currently 3:08PM here, despite our MySQL instance thinking it's 2am. The system time on the machine is correct:

$ date
Wed Jun 26 15:08:56 PDT 2013

This is MySQL 5.1.46 running on solaris2.10.

Any ideas short of restarting the MySQL engine? I'm willing to do that, but would much rather wait and not do it in the middle of the day.

Answer 1

This is the expected behavior if you set the timestamp variable in your session. This is the same mechanism that replication uses to execute transactions on the slave with the correct time. Setting timestamp back to default or reopening your connection will fix it.

> set timestamp=**********;
Query OK, 0 rows affected (0.00 sec)

> select now(); select sleep(5); select now();
+---------------------+
| now() |
+---------------------+
| 2013-06-26 21:32:17 |
+---------------------+
1 row in set (0.00 sec)

+----------+
| sleep(5) |
+----------+
| 0 |
+----------+
1 row in set (5.00 sec)

+---------------------+
| now() |
+---------------------+
| 2013-06-26 21:32:17 |
+---------------------+
1 row in set (0.00 sec)

> set timestamp=default;
Query OK, 0 rows affected (0.00 sec)

> select now();
+---------------------+
| now() |
+---------------------+
| 2013-06-26 21:33:53 |
+---------------------+
1 row in set (0.00 sec)

> select now();
+---------------------+
| now() |
+---------------------+
| 2013-06-26 21:33:54 |
+---------------------+
1 row in set (0.00 sec)