25.2 Performance Schema Build Configuration
The Performance Schema is mandatory and always compiled in. It is possible to exclude certain parts of the Performance Schema instrumentation. For example, to exclude stage and statement instrumentation, do this:
shell> cmake . \ -DDISABLE_PSI_STAGE=1 \ -DDISABLE_PSI_STATEMENT=1
For more information, see the descriptions of the
DISABLE_PSI_ CMake options in Section 2.9.7, “MySQL Source-Configuration Options”.
If you install MySQL over a previous installation that was configured without the Performance Schema (or with an older version of the Performance Schema that has missing or out-of-date tables). One indication of this issue is the presence of messages such as the following in the error log:
[ERROR] Native table 'performance_schema'.'events_waits_history' has the wrong structure [ERROR] Native table 'performance_schema'.'events_waits_history_long' has the wrong structure ...
To correct that problem, perform the MySQL upgrade procedure. See Section 2.11, “Upgrading MySQL”.
To verify whether a server was built with Performance Schema support, check its help output. If the Performance Schema is available, the output will mention several variables with names that begin with
shell> mysqld --verbose --help ... --performance_schema Enable the performance schema. --performance_schema_events_waits_history_long_size=# Number of rows in events_waits_history_long. ...
mysql> SHOW ENGINES\G ... Engine: PERFORMANCE_SCHEMA Support: YES Comment: Performance Schema Transactions: NO XA: NO Savepoints: NO ...
If the Performance Schema was not configured into the server at build time, no row for
PERFORMANCE_SCHEMA will appear in the output from
SHOW ENGINES. You might see
performance_schema listed in the output from
SHOW DATABASES, but it will have no tables and you will not be able to use it.
A line for
PERFORMANCE_SCHEMA in the
SHOW ENGINES output means that the Performance Schema is available, not that it is enabled. To enable it, you must do so at server startup, as described in the next section.