MySQL 8.4 Release Notes
在读取非常大的 JSON 文档时，可能很难配对其关闭括号和打开括号；设置 end_markers_in_json=ON 会在关闭括号附近重复结构的键（如果有的话）。此变量会影响优化器跟踪以及 EXPLAIN FORMAT=JSON 的输出。When reading a very large JSON document, it can be difficult to
pair its closing bracket and opening brackets; setting
end_markers_in_json=ON repeats
the structure's key, if it has one, near the closing bracket.
This variable affects both optimizer traces and the output of
EXPLAIN FORMAT=JSON.
Note
如果启用了 end_markers_in_json，键的重复意味着结果不是有效的 JSON 文档，并会导致 JSON 解析器抛出错误。If end_markers_in_json is
enabled, the repetition of the key means the result is not a
valid JSON document, and causes JSON parsers to throw an error.