Performance Schema threads Table

Each server thread is represented as a row in the threads table.

The threads table contains the following columns:

Column	Description
THREAD_ID	A unique thread identifier.
NAME	Name associated with the server's thread instrumentation code, for example thread/sql/main for the server's main() function, and thread/sql/one_connection for a user connection.
TYPE	FOREGROUND or BACKGROUND, depending on the thread type. User connection threads are FOREGROUND, internal server threads are BACKGROUND.
PROCESSLIST_ID	The PROCESSLIST.ID value for threads displayed in the INFORMATION_SCHEMA.PROCESSLIST table, or 0 for background threads. Also corresponds with the CONNECTION_ID() return value for the thread.
PROCESSLIST_USER	Foreground thread user, or NULL for a background thread.
PROCESSLIST_HOST	Foreground thread host, or NULL for a background thread.
PROCESSLIST_DB	Thread's default database, or NULL if none exists.
PROCESSLIST_COMMAND	Type of command executed by the thread. These correspond to the COM_xxx client/server protocol commands, and the Com_xxx status variables. See Thread Command Values.
PROCESSLIST_TIME	Time in seconds the thread has been in its current state.
PROCESSLIST_STATE	Action, event or state indicating what the thread is doing.
PROCESSLIST_INFO	Statement being executed by the thread, or NULL if a statement is not being executed. If a statement results in calling other statements, such as for a stored procedure, the innermost statement from the stored procedure is shown here.
PARENT_THREAD_ID	THREAD_ID of the parent thread, if any. Subthreads can for example be spawned as a result of INSERT DELAYED statements.
ROLE	Unused.
INSTRUMENTED	YES or NO for Whether the thread is instrumented or not. For foreground threads, the initial value is determined by whether there's a user/host match in the setup_actors table. Subthreads are again matched, while for background threads, this will be set to YES by default. To monitor events that the thread executes, INSTRUMENTED must be YES and the thread_instrumentation consumer in the setup_consumers table must also be YES.
HISTORY	YES or NO for Whether to log historical events for the thread. For foreground threads, the initial value is determined by whether there's a user/host match in the setup_actors table. Subthreads are again matched, while for background threads, this will be set to YES by default. To monitor events that the thread executes, INSTRUMENTED must be YES and the thread_instrumentation consumer in the setup_consumers table must also be YES. Added in MariaDB 10.5.
CONNECTION_TYPE	The protocol used to establish the connection. One of TCP/IP, SSL/TLS, Socket, Named Pipe, Shared Memory, or NULL for background threads. Added in MariaDB 10.5.
THREAD_OS_ID	The thread or task identifier as defined by the underlying operating system, if there is one. Added in MariaDB 10.5

Example

SELECT * FROM performance_schema.threads\G; *************************** 1. row ***************************  THREAD_ID: 1  NAME: thread/sql/main  TYPE: BACKGROUND  PROCESSLIST_ID: NULL  PROCESSLIST_USER: NULL  PROCESSLIST_HOST: NULL  PROCESSLIST_DB: NULL PROCESSLIST_COMMAND: NULL  PROCESSLIST_TIME: 215859  PROCESSLIST_STATE: Table lock  PROCESSLIST_INFO: INTERNAL DDL LOG RECOVER IN PROGRESS  PARENT_THREAD_ID: NULL  ROLE: NULL  INSTRUMENTED: YES ... *************************** 21. row ***************************  THREAD_ID: 64  NAME: thread/sql/one_connection  TYPE: FOREGROUND  PROCESSLIST_ID: 44  PROCESSLIST_USER: root  PROCESSLIST_HOST: localhost  PROCESSLIST_DB: NULL PROCESSLIST_COMMAND: Query  PROCESSLIST_TIME: 0  PROCESSLIST_STATE: Sending data  PROCESSLIST_INFO: SELECT * FROM performance_schema.threads  PARENT_THREAD_ID: NULL  ROLE: NULL  INSTRUMENTED: YES

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