Key Monitoring Metrics of PD

If you use TiDB Ansible to deploy the TiDB cluster, the monitoring system is deployed at the same time. For more information, see Overview of the Monitoring Framework.

The Grafana dashboard is divided into a series of sub dashboards which include Overview, PD, TiDB, TiKV, Node_exporter, Disk Performance, and so on. A lot of metrics are there to help you diagnose.

You can get an overview of the component PD status from the PD dashboard, where the key metrics are displayed. This document provides a detailed description of these key metrics.

Key metrics description

To understand the key metrics displayed on the Overview dashboard, check the following table:

Service	Panel name	Description	Normal range
Cluster	PD role	The role of the current PD
Cluster	Storage capacity	The total capacity size of the cluster
Cluster	Current storage size	The current storage size of the cluster
Cluster	Current storage usage	The total number of Regions without replicas
Cluster	Normal stores	The count of healthy stores
Cluster	Abnormal stores	The count of unhealthy stores	The normal value is `0`. If the number is bigger than `0`, it means at least one instance is abnormal.
Cluster	Current peer count	The current peer count of the cluster
Cluster	Number of Regions	The total number of Regions of the cluster
Cluster	PD scheduler config	The list of PD scheduler configurations
Cluster	Region label isolation level	The number of Regions in different label levels
Cluster	Label distribution	The distribution status of the labels in the cluster
Cluster	pd_cluster_metadata	The metadata of the PD cluster including cluster ID, the timestamp, and the generated ID.
Cluster	Region health	The health status of Regions indicated via count of unusual Regions including pending peers, down peers, extra peers, offline peers, missing peers, learner peers and incorrect namespaces	The number of pending peers should be less than `100`. The missing peers should not be persistently greater than `0`.
Statistics - Balance	Store capacity	The capacity size per TiKV instance
Statistics - Balance	Store available	The available capacity size per TiKV instance
Statistics - Balance	Store used	The used capacity size per TiKV instance
Statistics - Balance	Size amplification	The size amplification ratio per TiKV instance, which is equal to (Store Region size)/(Store used capacity size)
Statistics - Balance	Size available ratio	The size availability ratio per TiKV instance, which is equal to (Store available capacity size)/(Store capacity size)
Statistics - Balance	Store leader score	The leader score per TiKV instance
Statistics - Balance	Store Region score	The Region score per TiKV instance
Statistics - Balance	Store leader size	The total leader size per TiKV instance
Statistics - Balance	Store Region size	The total Region size per TiKV instance
Statistics - Balance	Store leader count	The leader count per TiKV instance
Statistics - Balance	Store Region count	The Region count per TiKV instance
Statistics - Hotspot	Leader distribution in hot write Regions	The total number of leader Regions in hot write on each TiKV instance
Statistics - Hotspot	Peer distribution in hot write Regions	The total number of peer Regions under in hot write on each TiKV instance
Statistics - Hotspot	Leader written bytes in hot write Regions	The total written bytes by Leader regions in hot write on leader Regions for each TiKV instance
Statistics - Hotspot	Peer written bytes in hot write Regions	The total bytes of hot write on peer Regions per each TiKV instance
Statistics - Hotspot	Leader distribution in hot read Regions	The total number of leader Regions in hot read per each TiKV instance
Statistics - Hotspot	Peer distribution in hot read Regions	The total number of Regions which are not leader under hot read per each TiKV instance
Statistics - Hotspot	Leader read bytes in hot read Regions	The total bytes of hot read on leader Regions per each TiKV instance
Statistics - Hotspot	Peer read bytes in hot read Regions	The total bytes of hot read on peer Regions per TiKV instance
Scheduler	Running schedulers	The current running schedulers
Scheduler	Balance leader movement	The leader movement details among TiKV instances
Scheduler	Balance Region movement	The Region movement details among TiKV instances
Scheduler	Balance leader event	The count of balance leader events
Scheduler	Balance Region event	The count of balance Region events
Scheduler	Balance leader scheduler	The inner status of balance leader scheduler
Scheduler	Balance Region scheduler	The inner status of balance Region scheduler
Scheduler	Namespace checker	The namespace checker's status
Scheduler	Replica checker	The replica checker's status
Scheduler	Region merge checker	The merge checker's status
Operator	Schedule operator create	The number of newly created operators per type
Operator	Schedule operator check	The number of checked operator per type. It mainly checks if the current step is finished; if yes, it returns the next step to be executed.
Operator	Schedule operator finish	The number of finished operators per type
Operator	Schedule operator timeout	The number of timeout operators per type
Operator	Schedule operator replaced or canceled	The number of replaced or canceled operators per type
Operator	Schedule operators count by state	The number of operators per state
Operator	99% Operator finish duration	The operator step duration (P99)
Operator	50% Operator finish duration	The operator duration (P50)
Operator	99% Operator step duration	The operator step duration (P99)
Operator	50% Operator step duration	The operator step duration (P50)
gRPC	Completed commands rate	The rate per command type type at which gRPC commands are completed
gRPC	99% Completed commands duration	The rate per command type type at which gRPC commands are completed (P99)
etcd	Transaction handling rate	The rate at which etcd handles transactions
etcd	99% transactions duration	The transaction handling rate (P99)
etcd	99% WAL fsync duration	The time consumed for writing WAL into the persistent storage (P99)	The value is less than `1s`.
etcd	99% Peer round trip time seconds	The network latency for etcd (P99)	The value is less than `1s`.
etcd	etcd disk wal fsync rate	The rate of writing WAL into the persistent storage
etcd	Raft term	The current term of Raft
etcd	Raft committed index	The last committed index of Raft
etcd	Raft applied index	The last applied index of Raft
TiDB	Handled requests count	The count of TiDB requests
TiDB	Request handling duration	The time consumed for handling TiDB requests	It should be less than `100ms` (P99).
Heartbeat	Region heartbeat report	The count of heartbeats reported reported to PD per instance
Heartbeat	Region heartbeat report error	The count of heartbeats with the `error` status
Heartbeat	Region heartbeat report active	The count of heartbeats with the `ok` status
Heartbeat	Region schedule push	The count of corresponding schedule commands sent from PD per TiKV instance
Heartbeat	99% Region heartbeat latency	The heartbeat latency per TiKV instance (P99)
Region storage	Syncer index	The maximum index in the Region change history recorded by the leader
Region storage	History last index	The last index where the Region change history is synchronized successfully with the follower