【Error】mysql的error.log中ranges: 268 max_threads: 4 split: 268 depth: 2是什么意思？

2021-12-08T09:36:39.612332+08:00 44213799 [Note] [MY-011825] [InnoDB] Parallel scan: 4
2021-12-08T09:36:39.625789+08:00 44213799 [Note] [MY-011825] [InnoDB] ranges: 268 max_threads: 4 split: 268 depth: 2
2021-12-08T09:36:40.833297+08:00 44213799 [Note] [MY-011825] [InnoDB] n: 1607540
2021-12-08T09:36:40.833339+08:00 44213799 [Note] [MY-011825] [InnoDB] n: 1684951
2021-12-08T09:36:40.833345+08:00 44213799 [Note] [MY-011825] [InnoDB] n: 1592299
2021-12-08T09:36:40.833351+08:00 44213799 [Note] [MY-011825] [InnoDB] n: 1754693

这是mysql8.0.14版本新增的并行查询特性产生的日志。
上述error log中记录并行扫描聚集索引信息的功能在8.0.20中又被去掉了。

参考文章：https://www.yht7.com/news/25300
参考文章：https://cloud.tencent.com/developer/article/1650219