Overview of the MySQL Connections dashboard (4370386)

The Connections page shows graphs of some key connection metrics and three tabs with more information:

• Current Connections - The MySQL process list at the time of the last sample
  
  

  

   

• Failed Logins – This section shows all hosts that have made failed login attempts in the selected time range, along with error counts for all connection error types.  The data is retrieved from the performance_schema.host_cache on the MySQL server itself so that networking or firewall issues will not be captured since only the client would know about these types of issues. There is a database connectivity rule is run based on the result of the frequent connection status sample, but this triggers for the agent's persistent inability to reach the server and would generate an alarm based on the Connectivity %, also viewable on the Server | Connection Status tab. Users will not going to be able to find out that random clients can't even reach the server the user is watching the clients or the networking component blocking them.
  

The following columns are available as of the 7.3.0.13 cartridge.

• • total: Total number of connection errors in the selected period.
  • sum_connect: The number of connection errors that are deemed “blocking” (assessed against the max_connect_errors system variable). Only protocol handshake errors are counted, and only for hosts that passed validation (HOST_VALIDATED = YES).
  • host_blocked: The number of connections that were blocked because SUM_CONNECT_ERRORS exceeded the value of the max_connect_errors system variable.
  • nameinfo_transient: The number of transient errors during IP-to-host name DNS resolution.
  • nameinfo_permanent: The number of permanent errors during IP-to-host name DNS resolution.
    format": The number of host name format errors. MySQL does not perform matching of Host column values in the mysql.user table against host names for which one or more of the initial components of the name are entirely numeric, such as 1.2.example.com. The client IP address is used instead. For the rationale why this type of matching does not occur, see Section 6.2.3, “Specifying Account Names”.
  • addrinfo_transient: The number of transient errors during host name-to-IP reverse DNS resolution.
  • addrinfo_permanent: The number of permanent errors during host name-to-IP reverse DNS resolution.
  • fcrdns: The number of forward-confirmed reverse DNS errors. These errors occur when IP-to-host name-to-IP DNS resolution produces an IP address that does not match the client originating IP address.
  • host_acl: The number of errors that occur because no user from the client host can possibly log in. In such cases, the server returns ER_HOST_NOT_PRIVILEGED and does not even ask for a user name or password.
  • no_auth_plugin: The number of errors due to requests for an unavailable authentication plugin. A plugin can be unavailable if, for example, it was never loaded or a load attempt failed.
  • auth_plugin: The number of errors reported by authentication plugins. An authentication plugin can report different error codes to indicate the root cause of a failure. Depending on the type of error, one of these columns is incremented: COUNT_AUTHENTICATION_ERRORS, COUNT_AUTH_PLUGIN_ERRORS, COUNT_HANDSHAKE_ERRORS. New return codes are an optional extension to the existing plugin API. Unknown or unexpected plugin errors are counted in the COUNT_AUTH_PLUGIN_ERRORS column.
  • handshake: The number of errors detected at the wire protocol level.
  • proxy_user: The number of errors detected when a proxy user A is proxied to another user B who does not exist.
  • proxy_user_acl: The number of errors detected when a proxy user A is proxied to another user B who does exist but for whom A does not have the PROXY privilege.
  • authentication: The number of errors caused by failed authentication.
  • ssl: The number of errors due to SSL problems.
  • max_user_connections: The number of errors caused by exceeding per-user connection quotas. See Section 6.3.4, 'Setting Account Resource Limits'.
  • max_user_connections_per_hour: The number of errors caused by exceeding per-user connections-per-hour quotas. See Section 6.3.4, 'Setting Account Resource Limits'.
  • default_database: The number of errors related to the default database. For example, the database did not exist or the user had no privileges for accessing it.
  • init_connect: The number of errors caused by execution failures of statements in the init_connect system variable value.
  • local: The number of errors local to the server implementation and not related to the network, authentication, or authorization. For example, out-of-memory conditions fall into this category.
  • unknown: The number of other, unknown errors not accounted for by other columns in this table. This column is reserved for future use, in case new error conditions must be reported, and if preserving the backward compatibility and table structure of the host_cache table is required.
• Users - A list of MySQL users and privileges, along with password status, current connections, and total connections in the selected time range
  
  

  

This video provides a brief overview of the dashboards.