The [existing work](https://github.com/apache/incubator-pinot/pull/6204/files#diff-2fc79d140ad00f4fe862b03a12674c564a3cd85bc59e5397cb706a51a19faa39R46) emits how many pks for the table. The new feature should emit metrics for how many memory for upsert metadata used for each table.
The existing work emits how many pks for the table.
The new feature should emit metrics for how many memory for upsert metadata used for each table.