Instance tables document what types of objects are instrumented. They provide event names and explanatory notes or status information:
cond_instances: Condition synchronization object instancesfile_instances: File instancesmutex_instances: Mutex synchronization object instancesrwlock_instances: Lock synchronization object instancessocket_instances: Active connection instances
These tables list instrumented synchronization objects, files, and connections. There are three types of synchronization objects:cond,mutex, andrwlock. Each instance table has anEVENT_NAME orNAME column to indicate the instrument associated with each row. Instrument names may have multiple parts and form a hierarchy, as discussed inChapter 7,Performance Schema Instrument Naming Conventions.
Themutex_instances.LOCKED_BY_THREAD_ID andrwlock_instances.WRITE_LOCKED_BY_THREAD_ID columns are extremely important for investigating performance bottlenecks or deadlocks. For examples of how to use them for this purpose, seeChapter 14,Using the Performance Schema to Diagnose Problems