27.1 Prerequisites for Using the sys Schema

Before using the sys schema, the prerequisites described in this section must be satisfied.

Because the sys schema provides an alternative means of accessing the Performance Schema, the Performance Schema must be enabled for the sys schema to work. See Section 26.3, “Performance Schema Startup Configuration”.

For full access to the sys schema, a user must have these privileges:

SELECT on all sys tables and views
EXECUTE on all sys stored procedures and functions
INSERT and UPDATE for the sys_config table, if changes are to be made to it
Additional privileges for certain sys schema stored procedures and functions, as noted in their descriptions (for example, the ps_setup_save() procedure)

It is also necessary to have privileges for the objects underlying the sys schema objects:

SELECT on any Performance Schema tables accessed by sys schema objects, and UPDATE for any tables to be updated using sys schema objects
PROCESS for the INFORMATION_SCHEMA INNODB_BUFFER_PAGE table

Certain Performance Schema instruments and consumers must be enabled and (for instruments) timed to take full advantage of sys schema capabilities:

All wait instruments
All stage instruments
All statement instruments
xxx_current and xxx_history_long consumers for all events

You can use the sys schema itself to enable all of the additional instruments and consumers:

CALL sys.ps_setup_enable_instrument('wait');
CALL sys.ps_setup_enable_instrument('stage');
CALL sys.ps_setup_enable_instrument('statement');
CALL sys.ps_setup_enable_consumer('current');
CALL sys.ps_setup_enable_consumer('history_long');

Note

For many uses of the sys schema, the default Performance Schema is sufficient for data collection. Enabling all the instruments and consumers just mentioned has a performance impact, so it is preferable to enable only the additional configuration you need. Also, remember that if you enable additional configuration, you can easily restore the default configuration like this:

CALL sys.ps_setup_reset_to_default(TRUE);

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Document created the 26/06/2006, last modified the 26/10/2018
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References

Manuel MySQL : https://dev.mysql.com/

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