Stats loaded from json file have wrong status

[xuyifangreeneyes]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

Start a v4.0.15 cluster

use test;
create table t(a int, b int);
-- insert some rows and wait for stats delta dump

Get stats json file test_t_stats.json through http api.

{
 "database_name": "test",
 "table_name": "t",
 "columns": {
  "a": {
   "histogram": {
    "ndv": 0
   },
   "cm_sketch": null,
   "null_count": 0,
   "tot_col_size": 256,
   "last_update_version": 440718415728738305,
   "correlation": 0
  },
  "b": {
   "histogram": {
    "ndv": 0
   },
   "cm_sketch": null,
   "null_count": 0,
   "tot_col_size": 256,
   "last_update_version": 440718415728738305,
   "correlation": 0
  }
 },
 "indices": {},
 "count": 256,
 "modify_count": 256,
 "partitions": null
}

Start a v6.5.1 cluster

mysql> use test;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> load stats 'test_t_stats.json';
Query OK, 0 rows affected (0.36 sec)

mysql> show stats_meta;
+---------+------------+----------------+---------------------+--------------+-----------+
| Db_name | Table_name | Partition_name | Update_time         | Modify_count | Row_count |
+---------+------------+----------------+---------------------+--------------+-----------+
| test    | t          |                | 2023-04-11 18:11:23 |          256 |       256 |
+---------+------------+----------------+---------------------+--------------+-----------+
1 row in set (0.10 sec)

mysql> show stats_histograms;
+---------+------------+----------------+-------------+----------+---------------------+----------------+------------+--------------+-------------+-------------+-----------------+----------------+----------------+---------------+
| Db_name | Table_name | Partition_name | Column_name | Is_index | Update_time         | Distinct_count | Null_count | Avg_col_size | Correlation | Load_status | Total_mem_usage | Hist_mem_usage | Topn_mem_usage | Cms_mem_usage |
+---------+------------+----------------+-------------+----------+---------------------+----------------+------------+--------------+-------------+-------------+-----------------+----------------+----------------+---------------+
| test    | t          |                | a           |        0 | 2023-04-11 18:11:22 |              0 |          0 |            1 |           0 | allEvicted  |               0 |              0 |              0 |             0 |
| test    | t          |                | b           |        0 | 2023-04-11 18:11:23 |              0 |          0 |            1 |           0 | allEvicted  |               0 |              0 |              0 |             0 |
+---------+------------+----------------+-------------+----------+---------------------+----------------+------------+--------------+-------------+-------------+-----------------+----------------+----------------+---------------+
2 rows in set (0.00 sec)

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

Since no stats are collected, columns a and b should not appear in show stats_histograms.

3. What did you see instead (Required)

Since no stats are collected, columns a and b appear in show stats_histograms and their status is allEvicted.

4. What is your TiDB version? (Required)

v6.5.1