upgrade tidb cluster, the default of tidb_cost_model_version is unreasonable

[ChenPeng2013]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

upgrade tidb cluster from 6.0.0 to nightly

tiup cluster deploy cp-test v6.0.0  topology.yaml
tiup cluster upgrade cp-test nightly

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

MySQL [test]> select @@tidb_cost_model_version;
+---------------------------+
| @@tidb_cost_model_version |
+---------------------------+
| 1                         |
+---------------------------+
1 row in set (0.00 sec)

3. What did you see instead (Required)

MySQL [test]> select @@tidb_cost_model_version;
+---------------------------+
| @@tidb_cost_model_version |
+---------------------------+
| 2                         |
+---------------------------+
1 row in set (0.00 sec)

4. What is your TiDB version? (Required)

| Release Version: v6.5.0-alpha
Edition: Community
Git Commit Hash: 30a84140e597e9eafca6aa64edb752e0518f0f5e
Git Branch: heads/refs/tags/v6.5.0-alpha
UTC Build Time: 2022-11-30 14:34:05
GoVersion: go1.19.3
Race Enabled: false
TiKV Min Version: 6.2.0-alpha
Check Table Before Drop: false
Store: tikv |