Weekly documentation feedback from readers

[github-actions]

Feedback from readers

Three sections: feedback, top working searches, and top failed searches.
Please check off the feedback and failed searches as you fix them and
please add the label to your PRs related to this issue.

You do not need to edit this issue with PR numbers, as everything with
the label will show in the GitHub project.

• /docs/unloading/Flink_connector/
  feedback: No flink cdc example, when use StarRocks as a data source.
  Rating: 1/5
  timestamp: 2024-04-30T04:19:50.868000Z
• /docs/sql-reference/sql-statements/generated_columns/
  feedback: not appropirate.
  Rating: 1/5
  timestamp: 2024-05-01T12:31:02.884000Z
• /zh/docs/3.0/sql-reference/sql-functions/string-functions/substring/
  feedback: 例子不够多，比如我需要截取字符串中，从某个单词到另一个单词之间的字段
  Rating: 1/5
  timestamp: 2024-04-30T08:21:31.683000Z
• /zh/docs/sql-reference/sql-functions/bitmap-functions/bitmap_union
  feedback: null
  Rating: 5/5
  timestamp: 2024-05-04T09:48:32.983000Z
• /zh/docs/table_design/indexes/indexes_overview/
  feedback: null
  Rating: 5/5
  timestamp: 2024-04-30T08:19:59.633000Z

Algolia top searches

Note: Searches with zero hits are searches that are very popular and also not returning any results. They will also appear in the failed search list.

• 分区
  count this week: 83
  Search hits: 711

• alter table
  count this week: 68
  Search hits: 212

• 物化视图
  count this week: 68
  Search hits: 680

• count this week: 56
  Search hits: 8913

• json
  count this week: 45
  Search hits: 371

• array
  count this week: 42
  Search hits: 428

• create table
  count this week: 41
  Search hits: 583

• profile
  count this week: 41
  Search hits: 543

• bitmap
  count this week: 40
  Search hits: 401

• compaction
  count this week: 39
  Search hits: 130

Algolia top failed searches

• shu'ju
  failures this week: 21
• cha'kan
  failures this week: 20
• wai'biao
  failures this week: 13
• in_memory
  failures this week: 13
• pi'liang
  failures this week: 12
• ziduan
  failures this week: 12
• yibu
  failures this week: 12
• shitu
  failures this week: 11
• pi'li'a
  failures this week: 11
• cha'xun
  failures this week: 10