`information_schema.feedback.*`

show items implemented by

any at least two only one database all databases

relation	column	mysql	mariadb	tidb	postgres	cockroachdb	mssql
`feedback`
	`variable_name`	unsupported	`NULL`: 5.1-10.8	unsupported	unsupported	unsupported	unsupported
	`variable_value`	unsupported	`NULL`: 5.1-10.8	unsupported	unsupported	unsupported	unsupported