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Performance Schema Instrument Naming Conventions

An instrument name consists of a sequence of components separated by • / •

characters. Example

names:

wait/io/file/myisam/log

wait/io/file/mysys/char3et

wait/lock/table/sql/handler

wait/synch/cond/mysys/COND_alarm

wait/synch/cond/sql/BINLOG::update_cond

wait/synch/mutex/mysys/BITMAP_inutex

wait/synch/mutex/sql/LOCK_delete

wait/synch/rwlock/sql/Query_cache_query::lock

3tage/3ql/closing tables

3tage/sql/Sorting result

statement/com/Execute

statement/com/Query

statement/sql/create_table

statement/sql/lock_tables

The instrument name space has a tree-like structure. The components of an instrument name from left

to right provide a progression from morę generał to morę specific. The number of

components a name

has depends on the type of instrument.

The interpretation of a given component in a name depends on the components to the left of it. For

example, myisam appears in both of the following names, but myisam in the first name is related to file

l/O, whereas in the second it is related to a synchronization instrument:

wait/io/file/myi3am/log

wait/3ynch/cond/myi3am/MI_S0RT_INF0::cond

Instrument names consist of a prefix with a structure defined by the Performance Schema

implementation and a suffix defined by the developer implementing the instrument codę. The toplevel

component of an instrument prefix indicates the type of instrument. This component also

determines which event timer in the setup_timers table applies to the instrument. For the prefix part

of instrument names, the top level indicates the type of instrument.

The suffix part of instrument names comes from the codę for the instruments themselves. Suffixes may include levels such as these:

•    A name for the major component (a server module such as myisam, innodb, mysys, or sql) or a

plugin name.

•    The name of a variable in the codę, in the form XXX (a global variable) or

CCC: :MMM (a member MW

in class CCC). Examples: COND_thread_cache, THR_LOCK_myisam,

BINLOG::LOCK index.