The database name performance_schema
is
lowercase. The names of tables in the database are uppercase.
Normal case sensitivity rules apply, so on systems with
case-sensitive file names, the database name and table names must
be specified in the lettercase just indicated. This behavior can
be modified by setting the
lower_case_table_names
system
variable.
Most tables in the performance_schema
database
are read only and cannot be modified. Some of the setup tables
have columns that can be modified to affect Performance Schema
operation. Truncation is allowed to clear collected events or
aggregation counters, so TRUNCATE
TABLE
can be used on tables containing those kinds of
information, such as tables named with a prefix of
EVENTS_WAITS
.
Privileges are as for other databases and tables:
To retrieve from performance_schema
tables,
you must have the SELECT
privilege.
To change those columns that can be modified, you must have
the UPDATE
privilege.
To truncate tables that can be truncated, you must have the
DROP
privilege.