TableFullScan uses pseudo stats in determinate mode

[pcqz]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

Create a table without indexes, and insert some rows of data. Wait a minute and analyze the table.

mysql> show stats_meta;
+---------+------------+----------------+---------------------+--------------+-----------+
| Db_name | Table_name | Partition_name | Update_time         | Modify_count | Row_count |
+---------+------------+----------------+---------------------+--------------+-----------+
| test    | test       |                | 2023-11-03 10:07:27 |            0 |      2048 |
+---------+------------+----------------+---------------------+--------------+-----------+
1 row in set (0.00 sec)

mysql> explain select * from test;
+-----------------------+---------+-----------+---------------+----------------------+
| id                    | estRows | task      | access object | operator info        |
+-----------------------+---------+-----------+---------------+----------------------+
| TableReader_5         | 2048.00 | root      |               | data:TableFullScan_4 |
| └─TableFullScan_4     | 2048.00 | cop[tikv] | table:test    | keep order:false     |
+-----------------------+---------+-----------+---------------+----------------------+
2 rows in set (0.00 sec)

mysql> set tidb_opt_objective='determinate';
Query OK, 0 rows affected (0.00 sec)

mysql> explain select * from test;
+-----------------------+----------+-----------+---------------+--------------------------------+
| id                    | estRows  | task      | access object | operator info                  |
+-----------------------+----------+-----------+---------------+--------------------------------+
| TableReader_5         | 10000.00 | root      |               | data:TableFullScan_4           |
| └─TableFullScan_4     | 10000.00 | cop[tikv] | table:test    | keep order:false, stats:pseudo |
+-----------------------+----------+-----------+---------------+--------------------------------+
2 rows in set (0.00 sec)

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

In both modes, the TableFullScan has the correct row count.

3. What did you see instead (Required)

In determinate mode, the TableFullScan has a row count of 10000.

4. What is your TiDB version? (Required)

v7.6.0-alpha-nightly-20231101

[pcqz]

/found gs

[seiya-annie]

discussed with dev, maybe no need to cherry-pick to 6.1,6.5,7.1

[time-and-fate]

This issue only affects v7.5.