Performance Schema mutex_instances Table
Description
The mutex_instances
table lists all mutexes that the Performance Schema seeing while the server is executing.
A mutex is a code mechanism for ensuring that threads can only access resources one at a time. A second thread attempting to access a resource will find it protected by a mutex, and will wait for it to be unlocked.
The performance_schema_max_mutex_instances system variable specifies the maximum number of instrumented mutex instances.
Column
Description
NAME
Instrument name associated with the mutex.
OBJECT_INSTANCE_BEGIN
Memory address of the instrumented mutex.
LOCKED_BY_THREAD_ID
The THREAD_ID of the locking thread if a thread has a mutex locked, otherwise NULL.
This page is licensed: CC BY-SA / Gnu FDL
PreviousPerformance Schema metadata_locks TableNextPerformance Schema objects_summary_global_by_type Table
Last updated
Was this helpful?