add Observability part

Signed-off-by: y_static_y@sina.com <y_static_y@sina.com>

docs/design/2022-12-07-keyspace.md

@@ -101,6 +101,14 @@ Previously, there was only one GCWorker leader for GC in the entire PD and TiKV
 
 * When a specified keyspace uses keyspace level GC, this keyspace will have its own GCWorker leader that computes its own GC safe point, resolves locks, and deletes ranges. The keyspace level safe point information is stored in PD, isolated by the keyspace prefix, and only GC the data within its keyspace range, without affecting other keyspaces.
 
+#### Observability
+
+Keyspace observability is essential for understanding and managing performance effectively.
+
+1. Metric Filtering: TiDB metrics can be filtered by the `keyspace_id` label for precise monitoring.
+2. Grafana Setup: Add a query box for `keyspace_id` in Grafana dashboards to visualize data specific to each keyspace.
+3. Log Enhancement: Include the `keyspace_name` label in TiDB logs for better tracking and context in log analysis.
+
 ### TiKV
 
 `Keyspace` can only be used when TiKV [enabled API V2](https://github.com/tikv/rfcs/blob/master/text/0069-api-v2.md#tikv-server).
@@ -200,11 +208,3 @@ TiFlash requests carry the keyspace prefix. TiFlash parses `<KeyspaceID, TableID
 ### Placement Rules
 
 Placement rules are isolated by keyspace. TiDB must name placement rules using the keyspace prefix, such as `keyspace-<keyspace_id>-xxxx`. Additionally, the key range of some rules must be encoded.
-
-### Observability
-
-Keyspace observability is essential for understanding and managing performance effectively.
-
-1. Metric Filtering: TiDB metrics can be filtered by the `keyspace_id` label for precise monitoring.
-2. Grafana Setup: Add a query box for `keyspace_id` in Grafana dashboards to visualize data specific to each keyspace.
-3. Log Enhancement: Include the `keyspace_name` label in TiDB logs for better tracking and context in log analysis.