Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

Enable tidb_enable_reuse_chunk and read some data from tiflash.

2. What did you expect to see? (Required)

TiDB release the memory after the SQL is finished.

3. What did you see instead (Required)

TiDB will hold the memory util the connection is closed.

4. What is your TiDB version? (Required)

master, v6.5