pd-server v2.0.0

• Support Region Merge, to merge empty Regions after deleting data [experimental]
• Support Raft Learner [experimental]
• Optimize the scheduler
  • Make the scheduler to adapt to different Region sizes
  • Improve the priority and speed of restoring data during TiKV outage
  • Speed up data transferring when removing a TiKV node
  • Optimize the scheduling policies to prevent the disks from becoming full when the space of TiKV nodes is insufficient
  • Improve the scheduling efficiency of the balance-leader scheduler
  • Reduce the scheduling overhead of the balance-region scheduler
  • Optimize the execution efficiency of the the hot-region scheduler
• Operations interface and configuration
  • Support TLS
  • Support prioritizing the PD leaders
  • Support configuring the scheduling policies based on labels
  • Support configuring stores with a specific label not to schedule the Raft leader
  • Support splitting Region manually to handle the hotspot in a single Region
  • Support scattering a specified Region to manually adjust Region distribution in some cases
  • Add check rules for configuration parameters and improve validity check of the configuration items
• Debugging interface
  • Add the Drop Region debugging interface
  • Add the interfaces to enumerate the health status of each PD
• Statistics
  • Add statistics about abnormal Regions
  • Add statistics about Region isolation level
  • Add scheduling related metrics
• Performance
  • Keep the PD leader and the etcd leader together in the same node to improve write performance
  • Optimize the performance of Region heartbeat