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 permitted to clear collected events, so
TRUNCATE TABLE
can be used on
tables containing those kinds of information, such as tables named
with a prefix of events_waits_
.
TRUNCATE TABLE
can also be used
with summary tables, but the effect is to reset the summary
columns to 0 or NULL
, not to remove rows.
Privileges are as for other databases and tables: