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
MySQL protocol), and manipulation of prepared statements. Many
of these commands are used only by the MySQL 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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