Command Probes

The command probes are executed before and after a client command is executed, including any SQL statement that might be executed during that period. Commands include operations such as the initialization of the DB, use of the COM_CHANGE_USER operation (supported by the MariaDB protocol), and manipulation of prepared statements. Many of these commands are used only by the MariaDB client API from various connectors such as PHP and Java.

command-start(connectionid, command, user, host)
command-done(status)

• command-start: Triggered when a command is submitted to the server.
  • connectionid: The connection ID of the client executing the command.
  • command: An integer representing the command that was executed. Possible values are shown in the following table.

    Value	Name	Description
    00	COM_SLEEP	Internal thread state
    01	COM_QUIT	Close connection
    02	COM_INIT_DB	Select database (USE ...)
    03	COM_QUERY	Execute a query
    04	COM_FIELD_LIST	Get a list of fields
    05	COM_CREATE_DB	Create a database (deprecated)
    06	COM_DROP_DB	Drop a database (deprecated)
    07	COM_REFRESH	Refresh connection
    08	COM_SHUTDOWN	Shutdown server
    09	COM_STATISTICS	Get statistics
    10	COM_PROCESS_INFO	Get processes (SHOW PROCESSLIST)
    11	COM_CONNECT	Initialize connection
    12	COM_PROCESS_KILL	Kill process
    13	COM_DEBUG	Get debug information
    14	COM_PING	Ping
    15	COM_TIME	Internal thread state
    16	COM_DELAYED_INSERT	Internal thread state
    17	COM_CHANGE_USER	Change user
    18	COM_BINLOG_DUMP	Used by a replication slave or mysqlbinlog to initiate a binary log read
    19	COM_TABLE_DUMP	Used by a replication slave to get the master table information
    20	COM_CONNECT_OUT	Used by a replication slave to log a connection to the server
    21	COM_REGISTER_SLAVE	Used by a replication slave during registration
    22	COM_STMT_PREPARE	Prepare a statement
    23	COM_STMT_EXECUTE	Execute a statement
    24	COM_STMT_SEND_LONG_DATA	Used by a client when requesting extended data
    25	COM_STMT_CLOSE	Close a prepared statement
    26	COM_STMT_RESET	Reset a prepared statement
    27	COM_SET_OPTION	Set a server option
    28	COM_STMT_FETCH	Fetch a prepared statement

  • user: The user executing the command.
  • host: The client host.
• command-done: Triggered when the command execution completes. The status argument contains 0 if the command executed successfully, or 1 if the statement was terminated before normal completion.

The command-start and command-done probes are best used when combined with the statement probes to get an idea of overall execution time.

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