Editing 排除 MySQL 技術疑難問題 (section)

=== MySQL 伺服器已斷開 (has gone away) ===
步驟
* 在 MySQL 設定檔啟用 {{kbd | key = log_error}} 選項，例如 {{kbd | key = <nowiki>log_error="file_name_of_error_log"</nowiki>}}<ref>[https://dev.mysql.com/doc/refman/8.0/en/error-log.html MySQL :: MySQL 8.0 Reference Manual :: 5.4.2 The Error Log]</ref>。
* 範例錯誤日誌位於 {{kbd | key = <nowiki>file_name_of_error_log</nowiki>}} 如下：

<pre>
2019-05-23T08:52:19.989876Z 99980 [Note] 中斷連接 99980 到資料庫：'DB_NAME' 用戶：'DB_USER' 主機：'localhost' (收到的封包大於 'max_allowed_packet' 位元組)
</pre>

* 如果 MySQL 用戶具有 {{kbd | key = <nowiki>SUPER</nowiki>}} 權限<ref>[https://dev.mysql.com/doc/refman/8.0/en/privileges-provided.html MySQL :: MySQL 8.0 Reference Manual :: 6.2.2 Privileges Provided by MySQL]</ref>，則增加 {{kbd | key = <nowiki>max_allowed_packet</nowiki>}} 的值<ref>[https://stackoverflow.com/questions/5688403/how-to-check-and-set-max-allowed-packet-mysql-variable php - how to check and set max_allowed_packet mysql variable - Stack Overflow]</ref>。