index time range got a over-estimation compared with v7.5.3 #65294
Description
Bug Report
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1. Minimal reproduce step (Required)
mysql> plan replayer load '/Users/tailingxiang/Downloads/replayer_4sl0h-c6Ucp4ioSjQFJ4Vw==_1766724135378196957.zip';
Query OK, 0 rows affected (0.203 sec)
mysql> explain format="verbose" SELECT * FROM db.table WHERE col_time >= '2025-12-22 04:00:00' AND col_time < '2025-12-22 05:00:00';
+-------------------------------+----------+--------------+-----------+--------------------------------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| id | estRows | estCost | task | access object | operator info |
+-------------------------------+----------+--------------+-----------+--------------------------------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| IndexLookUp_8 | 52187.58 | 103350518.05 | root | | |
| ├─IndexRangeScan_6(Build) | 52187.58 | 10620171.98 | cop[tikv] | table:table, index:index(col_time) | range:[2025-12-22 04:00:00,2025-12-22 05:00:00), keep order:false, stats:partial[uk_id:allEvicted, idx_session:allEvicted, idx_item:allEvicted...(more: 3 allEvicted)] |
| └─TableRowIDScan_7(Probe) | 52187.58 | 19511254.35 | cop[tikv] | table:table | keep order:false, stats:partial[uk_id:allEvicted, idx_session:allEvicted, idx_item:allEvicted...(more: 3 allEvicted)] |
+-------------------------------+----------+--------------+-----------+--------------------------------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
3 rows in set, 1 warning (0.007 sec)
mysql> select version();
+--------------------------+
| version() |
+--------------------------+
| 8.0.11-TiDB-v7.5.3-dirty |
+--------------------------+
1 row in set (0.005 sec)
mysql> plan replayer load '/Users/tailingxiang/Downloads/replayer_4sl0h-c6Ucp4ioSjQFJ4Vw==_1766724135378196957.zip';
Query OK, 0 rows affected (0.203 sec)
mysql> explain format="verbose" SELECT * FROM db.table WHERE col_time >= '2025-12-22 04:00:00' AND col_time < '2025-12-22 05:00:00';
+--------------------------------+-------------+----------------+-----------+--------------------------------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| id | estRows | estCost | task | access object | operator info |
+--------------------------------+-------------+----------------+-----------+--------------------------------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| IndexLookUp_11 | 10091419.40 | 19826583302.42 | root | | |
| ├─IndexRangeScan_9(Build) | 10091419.40 | 2053603847.90 | cop[tikv] | table:table, index:index(col_time) | range:[2025-12-22 04:00:00,2025-12-22 05:00:00), keep order:false, stats:partial[uk_id:unInitialized, idx_session:unInitialized, idx_item:unInitialized...(more: 2 unInitialized)] |
| └─TableRowIDScan_10(Probe) | 10091419.40 | 4319016330.25 | cop[tikv] | table:table | keep order:false, stats:partial[uk_id:unInitialized, idx_session:unInitialized, idx_item:unInitialized...(more: 2 unInitialized)] |
+--------------------------------+-------------+----------------+-----------+--------------------------------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
3 rows in set, 1 warning (0.006 sec)
mysql> select version();
+-----------------------------------------------------+
| version() |
+-----------------------------------------------------+
| 8.0.11-TiDB-v8.5.4-nextgen.202510.0-263-g704d4c88f0 |
+-----------------------------------------------------+
1 row in set (0.000 sec)
2. What did you expect to see? (Required)
next gen have some over estimation of index time range, not sure it's intended or not. while the actually is quite lower then expected
3. What did you see instead (Required)
normal estimation as before, pls feel free to reach me to get the replayer
4. What is your TiDB version? (Required)
next-gen & master