TiKV Engine Read Request Exceeds 2G on a Single Node

Note:
This topic has been translated from a Chinese forum by GPT and might contain errors.

Original topic: tikv的引擎读请求单节点读超2G

| username: TiDBer_fancy

[TiDB Usage Environment] Production Environment
[TiDB Version] 5.3.0
[Encountered Issue: Unified read pool CPU is maxed out, tikv’s engine read requests (tikv_engine_flow_bytes) exceed 2G on a single node, causing read and write requests to slow down…

What is the main cause of this issue?
What operations does tikv_engine_flow_bytes mainly perform?