Movatterモバイル変換

• connection_control_failed_connections_threshold: The number of consecutive failed connection attempts permitted to accounts before the server adds a delay for subsequent connection attempts. To disable failed-connection counting, setconnection_control_failed_connections_threshold to zero.

• connection_control_min_connection_delay: The minimum delay in milliseconds for connection failures above the threshold.

• connection_control_max_connection_delay: The maximum delay in milliseconds for connection failures above the threshold.

• The delay is zero up throughconnection_control_failed_connections_threshold consecutive failed connection attempts.

• Thereafter, the server adds an increasing delay for subsequent consecutive attempts, until a successful connection occurs. The initial unadjusted delays begin at 1000 milliseconds (1 second) and increase by 1000 milliseconds per attempt. That is, once delay has been activated for an account, the unadjusted delays for subsequent failed attempts are 1000 milliseconds, 2000 milliseconds, 3000 milliseconds, and so forth.

• The actual delay experienced by a client is the unadjusted delay, adjusted to lie within the values of theconnection_control_min_connection_delay andconnection_control_max_connection_delay system variables, inclusive.

• Once delay has been activated for an account, the first successful connection thereafter by the account also experiences a delay, but failure counting is reset for subsequent connections.

• Ifconnection_control_min_connection_delay andconnection_control_max_connection_delay are 1000 and 20000, the adjusted delays are the same as the unadjusted delays, up to a maximum of 20000 milliseconds. The fourth and subsequent failed connections are delayed by 1000 milliseconds, 2000 milliseconds, 3000 milliseconds, and so forth.

• Ifconnection_control_min_connection_delay andconnection_control_max_connection_delay are 1500 and 20000, the adjusted delays for the fourth and subsequent failed connections are 1500 milliseconds, 2000 milliseconds, 3000 milliseconds, and so forth, up to a maximum of 20000 milliseconds.

• Ifconnection_control_min_connection_delay andconnection_control_max_connection_delay are 2000 and 3000, the adjusted delays for the fourth and subsequent failed connections are 2000 milliseconds, 2000 milliseconds, and 3000 milliseconds, with all subsequent failed connections also delayed by 3000 milliseconds.

• connection_control_min_connection_delay cannot be set greater than the current value ofconnection_control_max_connection_delay.

• connection_control_max_connection_delay cannot be set less than the current value ofconnection_control_min_connection_delay.

• If the client user proxies another user, the account for failed-connection counting is the proxying user, not the proxied user. For example, ifexternal_user@example.com proxiesproxy_user@example.com, connection counting uses the proxying user,external_user@example.com, rather than the proxied user,proxy_user@example.com. Bothexternal_user@example.com andproxy_user@example.com must have valid entries in themysql.user system table and a proxy relationship between them must be defined in themysql.proxies_priv system table (seeSection 8.2.19, “Proxy Users”).

• If the client user does not proxy another user, but does match amysql.user entry, counting uses theCURRENT_USER() value corresponding to that entry. For example, if a useruser1 connecting from a hosthost1.example.com matches auser1@host1.example.com entry, counting usesuser1@host1.example.com. If the user matches auser1@%.example.com,user1@%.com, oruser1@% entry instead, counting usesuser1@%.example.com,user1@%.com, oruser1@%, respectively.

The server maintains information about which client hosts can possibly connect to the server (essentially the union of host values formysql.user entries). If a client attempts to connect from any other host, the server rejects the attempt at an early stage of connection setup:

ERROR 1130 (HY000): Host 'host_name' is notallowed to connect to this MySQL server

Because this type of rejection occurs so early,CONNECTION_CONTROL does not see it, and does not count it.

• TheConnection_control_delay_generated status variable indicates the number of times the server added a delay to its response to a failed connection attempt. This does not count attempts that occur before reaching the threshold defined by theconnection_control_failed_connections_threshold system variable.

• TheINFORMATION_SCHEMACONNECTION_CONTROL_FAILED_LOGIN_ATTEMPTS table provides information about the current number of consecutive failed connection attempts per account (user/host combination). This counts all failed attempts, regardless of whether they were delayed.

• All accumulated failed-connection counters are reset to zero.

• TheConnection_control_delay_generated status variable is reset to zero.

• TheCONNECTION_CONTROL_FAILED_LOGIN_ATTEMPTS table becomes empty.