The setup_threads
table lists
instrumented thread classes. It exposes thread class names and
attributes:
mysql> SELECT * FROM performance_schema.setup_threads\G
*************************** 1. row ***************************
NAME: thread/performance_schema/setup
ENABLED: YES
HISTORY: YES
PROPERTIES: singleton
VOLATILITY: 0
DOCUMENTATION: NULL
...
*************************** 4. row ***************************
NAME: thread/sql/main
ENABLED: YES
HISTORY: YES
PROPERTIES: singleton
VOLATILITY: 0
DOCUMENTATION: NULL
*************************** 5. row ***************************
NAME: thread/sql/one_connection
ENABLED: YES
HISTORY: YES
PROPERTIES: user
VOLATILITY: 0
DOCUMENTATION: NULL
...
*************************** 10. row ***************************
NAME: thread/sql/event_scheduler
ENABLED: YES
HISTORY: YES
PROPERTIES: singleton
VOLATILITY: 0
DOCUMENTATION: NULL
The setup_threads
table has these
columns:
NAME
The instrument name. Thread instruments begin with
thread
(for example,thread/sql/parser_service
orthread/performance_schema/setup
).ENABLED
Whether the instrument is enabled. The value is
YES
orNO
. This column can be modified, although settingENABLED
has no effect for threads that are already running.For background threads, setting the
ENABLED
value controls whetherINSTRUMENTED
is set toYES
orNO
for threads that are subsequently created for this instrument and listed in thethreads
table. For foreground threads, this column has no effect; thesetup_actors
table takes precedence.HISTORY
Whether to log historical events for the instrument. The value is
YES
orNO
. This column can be modified, although settingHISTORY
has no effect for threads that are already running.For background threads, setting the
HISTORY
value controls whetherHISTORY
is set toYES
orNO
for threads that are subsequently created for this instrument and listed in thethreads
table. For foreground threads, this column has no effect; thesetup_actors
table takes precedence.PROPERTIES
The instrument properties. This column uses the
SET
data type, so multiple flags from the following list can be set per instrument:singleton
: The instrument has a single instance. For example, there is only one thread for thethread/sql/main
instrument.user
: The instrument is directly related to user workload (as opposed to system workload). For example, threads such asthread/sql/one_connection
executing a user session have theuser
property to differentiate them from system threads.
VOLATILITY
The instrument volatility. This column has the same meaning as in the
setup_instruments
table. See Section 29.12.2.3, “The setup_instruments Table”.DOCUMENTATION
A string describing the instrument purpose. The value is
NULL
if no description is available.
The setup_threads
table has these
indexes:
Primary key on (
NAME
)
TRUNCATE TABLE
is not permitted
for the setup_threads
table.