I received this - lock wait timeout exceeded try restarting transaction - what should I do now?

If lock wait timeout exceeds try restarting transaction, You can set variable innodb_lock_wait_timeout=100 for lock time to 100 sec.

mysql> set innodb_lock_wait_timeout=100;

Query OK, 0 rows affected (0.02 sec)

mysql> show variables like 'innodb_lock_wait_timeout';

+--------------------------+-------+

| Variable_name | Value |

+--------------------------+-------+

| innodb_lock_wait_timeout | 100 |

+--------------------------+-------+

The transaction which is timeout, try to lock table which is hold by another process. and your timeout variable set with little number of second. so it shows error. You can see more status by the command.

SHOW ENGINE INNODB STATUSG

You can see list of locked tables by-

 show open tables where in_use>0;

Now see the thread which is using this table

  show full process list;

now you can kill that thread or wait to complete it.