The index region ID of the lineitem table is the same as the PRIMARY KEY REGION ID

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

Original topic: lineitem表的索引region id和PRIMARY KEY的REGION ID一样

| username: vincentLi

[Test Environment for TiDB] Testing
[TiDB Version] 6.5.3
[Reproduction Path]
tiup bench tpch --sf=1 prepare
Insert test data
SELECT * FROM INFORMATION_SCHEMA.TIKV_REGION_STATUS where DB_NAME=‘test’ and TABLE_NAME=‘lineitem’;
Query the region of the table
Found result:
lineitem.csv (499 bytes)
It can be seen that the region id of the index and the region id of the data in the lineitem table are both 2009. Why is this happening?