The sys schema helps you interpret the data collected from the performance_schema in an easy and more understandable form. performance_schema should be enabled for sys schema to work. To use the sys schema to its fullest extent, you need to enable all the consumers and timers on performance_schema, but this impacts the performance of the server. So, enable consumers for only those that you are looking for.
A view with the x$ prefix displays data in picoseconds, which is used by other tools for further processing; other tables are human readable.
Enable a instrument from the sys schema:
mysql> CALL sys.ps_setup_enable_instrument('statement');
+------------------------+
| summary |
+------------------------+
| Enabled 22 instruments |
+------------------------+
1 row in set (0.08 sec)
Query OK, 0 rows affected (0.08 sec)If you want to reset to default, do this:
mysql> CALL sys.ps_setup_reset_to_default(TRUE)\G
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