TPCH q8 return different result when running with TiFlash and TiKV

[windtalker]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

1. load tpch 10
2. running tpch q8 with tiflash enabled
3. running tpch q8 with tiflash disabled

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

running with tiflash and running with tikv should return the same result

3. What did you see instead (Required)

MySQL [test]> source /tmp/8.sql
+--------+---------------+-----------------+------------+
| o_year | c1            | c2              | mkt_share  |
+--------+---------------+-----------------+------------+
|   1995 | 86174753.6705 | 2184536777.5059 | 0.03944760 |
|   1996 | 85697154.4007 | 2216626585.7168 | 0.03866106 |
+--------+---------------+-----------------+------------+
2 rows in set (5.57 sec)

MySQL [test]> set tidb_isolation_read_engines='tikv';
Query OK, 0 rows affected (0.00 sec)

MySQL [test]> source /tmp/8.sql
+--------+---------------+-----------------+------------+
| o_year | c1            | c2              | mkt_share  |
+--------+---------------+-----------------+------------+
|   1995 | 86174753.6705 | 2184536777.5059 | 0.03944761 |
|   1996 | 85697154.4007 | 2216626585.7168 | 0.03866107 |
+--------+---------------+-----------------+------------+
2 rows in set (21.54 sec)

MySQL [test]> select 86174753.6705/2184536777.5059;
+-------------------------------+
| 86174753.6705/2184536777.5059 |
+-------------------------------+
|                    0.03944761 |
+-------------------------------+
1 row in set (0.01 sec)

And looks like the result of tikv is the right answer.

4. What is your TiFlash version? (Required)

master, v6.5

5. Investigate

In v6.1.3 the result is the same, but in v6.1.3 the final divide is calulated in TiDB, and in v6.5 and master, the final divide is pushed to TiFlash, I think it is related to this issue: #6462