24.18 The INFORMATION_SCHEMA PROCESSLIST Table
The MySQL process list indicates the operations currently being performed by the set of threads executing within the server. The
PROCESSLIST table is one source of process information. For a comparison of this table with other sources, see Sources of Process Information.
PROCESSLIST table has these columns:
The connection identifier. This is the same value displayed in the
Idcolumn of the
SHOW PROCESSLISTstatement, the
PROCESSLIST_IDcolumn of the Performance Schema
threadstable, and returned by the
CONNECTION_ID()function within the thread.
The MySQL user who issued the statement. A value of
system userrefers to a nonclient thread spawned by the server to handle tasks internally, for example, a delayed-row handler thread or an I/O or SQL thread used on replica hosts. For
system user, there is no host specified in the
unauthenticated userrefers to a thread that has become associated with a client connection but for which authentication of the client user has not yet occurred.
event_schedulerrefers to the thread that monitors scheduled events (see Section 23.4, “Using the Event Scheduler”).
The host name of the client issuing the statement (except for
system user, for which there is no host). The host name for TCP/IP connections is reported in
format to make it easier to determine which client is doing what.
The default database for the thread, or
NULLif none has been selected.
The type of command the thread is executing on behalf of the client, or
Sleepif the session is idle. For descriptions of thread commands, see Section 8.14, “Examining Server Thread (Process) Information”. The value of this column corresponds to the
COM_commands of the client/server protocol and
Com_status variables. See Section 5.1.9, “Server Status Variables”
The time in seconds that the thread has been in its current state. For a replica SQL thread, the value is the number of seconds between the timestamp of the last replicated event and the real time of the replica host. See Section 16.2.2, “Replication Implementation Details”.
An action, event, or state that indicates what the thread is doing. For descriptions of
STATEvalues, see Section 8.14, “Examining Server Thread (Process) Information”.
Most states correspond to very quick operations. If a thread stays in a given state for many seconds, there might be a problem that needs to be investigated.
The statement the thread is executing, or
NULLif it is executing no statement. The statement might be the one sent to the server, or an innermost statement if the statement executes other statements. For example, if a
CALLstatement executes a stored procedure that is executing a
INFOvalue shows the
PROCESSLISTis a nonstandard
Like the output from the
SHOW PROCESSLISTstatement, the
PROCESSLISTtable provides information about all threads, even those belonging to other users, if you have the
PROCESSprivilege. Otherwise (without the
PROCESSprivilege), nonanonymous users have access to information about their own threads but not threads for other users, and anonymous users have no access to thread information.
If an SQL statement refers to the
PROCESSLISTtable, MySQL populates the entire table once, when statement execution begins, so there is read consistency during the statement. There is no read consistency for a multi-statement transaction.
The following statements are equivalent:
SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST SHOW FULL PROCESSLIST