Oracle 5.0 Reference Manual page 2971

For additional background on password hashing and authentication, see
Hashing in MySQL".
C.5.2.5. Password Fails When Entered Interactively
MySQL client programs prompt for a password when invoked with a
that has no following password value:
shell> mysql -u user_name -p
Enter password:
On some systems, you may find that your password works when specified in an option file or on the
command line, but not when you enter it interactively at the
when the library provided by the system to read passwords limits password values to a small number of
characters (typically eight). That is a problem with the system library, not with MySQL. To work around
it, change your MySQL password to a value that is eight or fewer characters long, or put your password
in an option file.
C.5.2.6.
Host 'host_name' is blocked
If the following error occurs, it means that
given host that were interrupted in the middle:
Host 'host_name' is blocked because of many connection errors.
Unblock with 'mysqladmin flush-hosts'
The value of the
interrupted connection requests are permitted. (See
max_connect_errors
something is wrong (for example, that someone is trying to break in), and blocks the host from further
connections until you issue a
command.
By default,
mysqld
max_connect_errors
shell> mysqld_safe --max_connect_errors=10000 &
The value can also be set at runtime:
mysql> SET GLOBAL max_connect_errors=10000;
If you get the
verify that there is nothing wrong with TCP/IP connections from that host. If you are having network
problems, it does you no good to increase the value of the
C.5.2.7.
Too many connections
If you get a
Too many connections
that all available connections are in use by other clients.
The number of connections permitted is controlled by the
Its default value is 100. If you need to support more connections, you should set a larger value for this
variable.
actually permits
mysqld
reserved for use by accounts that have the
Common Errors When Using MySQL Programs
old clients. The
mysqli
PHP 5) is compatible with the improved password hashing employed in MySQL
4.1 and higher, and no special configuration of MySQL need be done to use this
MySQL client library. For more information about the
http://php.net/mysqli.
max_connect_errors
[467] failed requests without a successful connection,
FLUSH HOSTS
blocks a host after 10 connection errors. You can adjust the value by setting
[467] at server startup:
Host 'host_name' is blocked
max_connections+1
extension (stands for "MySQL, Improved"; added in
Enter password:
has received many connection requests from the
mysqld
[467] system variable determines how many successive
Section 5.1.4, "Server System
statement or execute a
error message for a given host, you should first
max_connect_errors
error when you try to connect to the
max_connections
[467] clients to connect. The extra connection is
[578] privilege. By granting the
SUPER
2951
extension, see
mysqli
Section 6.1.2.4, "Password
[231] or
--password -p
prompt. This occurs
Variables".) After
assumes that
mysqld
mysqladmin flush-hosts
[467] variable.
server, this means
mysqld
[467] system variable.
[578]
SUPER
option