如何让 MySQL 对窗口函数使用合适的索引而不是文件排序？

我正在使用 MySQL 版本8.0.38。

给出下表：

CREATE TABLE `url_alias` (
    `pid` INT UNSIGNED NOT NULL AUTO_INCREMENT,
    `src` VARCHAR(128) NOT NULL DEFAULT '' COLLATE 'utf8mb3_general_ci',
    `dst` VARCHAR(128) NOT NULL DEFAULT '' COLLATE 'utf8mb3_general_ci',
    PRIMARY KEY (`pid`) USING BTREE,
    INDEX `src_dst_pid` (`src`, `dst`, `pid` DESC) USING BTREE
)
COLLATE='utf8mb3_general_ci'
ENGINE=InnoDB
;

对该表进行以下查询：

SELECT *
FROM (
    SELECT ua.pid, ua.src, ua.dst, ROW_NUMBER() OVER w AS 'num'
    FROM url_alias ua
    WINDOW w AS (
        PARTITION BY ua.src, ua.dst 
        ORDER BY ua.pid DESC
    )
) t
WHERE t.num > 1

使用EXPLAIN FORMAT=JSON，我得到以下信息：

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "85537.71"
    },
    "table": {
      "table_name": "t",
      "access_type": "ALL",
      "rows_examined_per_scan": 760313,
      "rows_produced_per_join": 253412,
      "filtered": "33.33",
      "cost_info": {
        "read_cost": "60196.48",
        "eval_cost": "25341.23",
        "prefix_cost": "85537.71",
        "data_read_per_join": "191M"
      },
      "used_columns": [
        "pid",
        "src",
        "dst",
        "num"
      ],
      "attached_condition": "(`t`.`num` > 1)",
      "materialized_from_subquery": {
        "using_temporary_table": true,
        "dependent": false,
        "cacheable": true,
        "query_block": {
          "select_id": 2,
          "cost_info": {
            "query_cost": "838338.80"
          },
          "windowing": {
            "windows": [
              {
                "name": "w",
                "using_filesort": true,
                "filesort_key": [
                  "`src`",
                  "`dst`",
                  "`pid` desc"
                ],
                "functions": [
                  "row_number"
                ]
              }
            ],
            "cost_info": {
              "sort_cost": "760313.00"
            },
            "table": {
              "table_name": "ua",
              "access_type": "index",
              "key": "src_dst_pid",
              "used_key_parts": [
                "src",
                "dst",
                "pid"
              ],
              "key_length": "776",
              "rows_examined_per_scan": 760313,
              "rows_produced_per_join": 760313,
              "filtered": "100.00",
              "using_index": true,
              "cost_info": {
                "read_cost": "1994.50",
                "eval_cost": "76031.30",
                "prefix_cost": "78025.80",
                "data_read_per_join": "568M"
              },
              "used_columns": [
                "pid",
                "src",
                "dst"
              ]
            }
          }
        }
      }
    }
  }
}

这表明查询中指定的窗口正在导致文件排序，即使ROW_NUMBER() OVER (PARTITION BY src, dst ORDER BY pid DESC)应该等同于在src_dst_pid维护某些计数器变量的同时按顺序读取索引。

有什么可以做的事情来消除查询中的文件排序，或者这是查询规划器的一些限制？