# Region Merge Slow (A)

+ Grafana PD —> Region health

![left](./student-guide/diagram/25-Slow-region-merge-monitoring-and-phenomena-01-01.png)

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Region Merge is slow
Region merge refers to the process of merging adjacent small regions by scheduling in order to avoid large numbers of small or even empty regions consuming system resources after deleting data. Region merge is handled by MergeChecker. PD traverses the background and initiates a Merge dispatch after discovering contiguous small regions.
Problem phenomenon
Through the monitoring of the PD, we can see the presence of an empty region in the current cluster:
  - Grafana PD —> Region health