Can't SHOW GRANTS after MySQL re-install

Question

I had to completely re-install MySQL on one of the slaves and then rebuild it via a sql dump (we have 1 master and 2 slaves). I tried to SHOW GRANTS for one of the users, but keep getting the following error:

ERROR 1141 (42000): There is no such grant defined for user 'USER' on host '%'

I can SHOW GRANTS for root though. SHOW GRANTS needs a SELECT privilege for the mysql database, which root has:

mysql> show grants;
+---------------------------------------+
| Grants for root@localhost                                                             |
+---------------------------------------------------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' IDENTIFIED BY PASSWORD '*dfdfdfdf' WITH GRANT OPTION |
| GRANT PROXY ON ''@'' TO 'root'@'localhost' WITH GRANT OPTION                                           |
+-----+
2 rows in set (0.01 sec)

Btw, the privileges themselves exist, as I can select them from mysql.user table:

mysql> select update_priv, delete_priv from mysql.user where user like 'USER%';
+-------------+-------------+
| update_priv | delete_priv |
+-------------+-------------+
| Y           | Y           |
+-------------+-------------+
1 row in set (0.00 sec)

What am I missing?

Edit by RolandoMySQLDBA 2013-01-15 21:06 EDT

1) Please run SELECT VERSION(); to tell me what version of MySQL you are using

2) Please run SELECT COUNT(1) from information_schema.columns WHERE table_schema='mysql' AND table_name='user';

3) Please tell me from what version of mysql did the mysqldump come from.

Answer 1

Entries existing in the mysql.user table and privileges being recognized by the MySQL server are two different things that are only loosely-coupled.

mysql> FLUSH PRIVILEGES;

Any time you change the content of the mysql.user table, other than by issuing a GRANT ...-type statement, including restoring from a backup, you need to issue the FLUSH PRIVILEGES command before MySQL will realize those changes have happened. This should make the users visible.

Or, by now you may have restarted the server, which would also fix it.