mysqld 升級到8以上遇到的問題

coav4u

tid=187560&(1)
php連到mysql出現2行errors : (discuz網頁出現的是連接到mysql錯誤表格,需自行寫一隻連接mysql的php程式來測試)

3 @5 {2 _+ y- u6 L0 T7 ]mysqli_real_connect(): Server sent charset (255) unknown to the client. Please, report to the developers
' x2 T9 L+ I# }' y* s5 Omysqli_real_connect(): (HY000/2054): Server sent charset unknown to the client. Please, report to the developers
原因:
在MySQL 8.0.21中，caching_sha2_password是默認的身份驗證插件，而不是以往的mysql_native_password。所以和php不相容。可以降級php，也可以修改MySQL的配置。 吾人決定修改MySQL的配置:
9 m9 ^8 q4 i. u3 Avi /etc/my.cnf  加入下列:
% g# w  n1 w9 H/ F. d) V; B[mysqld]

character-set-server=utf8
/ N) {8 E" j/ j  ?default_authentication_plugin=mysql_native_password

[mysql]
6 r' }3 a, s: ddefault-character-set=utf8

5 z* \( i! m8 @! P" g! S( ~[client]
default-character-set=utf8
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然後重啟mysqld
service mysqld restart
搞定!!
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5 ]5 R" b1 f8 q0 a- n0 [, v" G註: mysqld啟動時,在/var/log/mysql/mysqld.log紀錄著:註: 可以先寫支php程式以測試 ~~~

1. <?
2. $hostname = "x.x.x.x";
3. $database = "db_name";
4. $username = "user_name";
5. $password = "pwd";
7. $conn = mysqli_connect($hostname, $username, $password,$database) or trigger_error(mysql_error(),E_USER_ERROR);
8. mysqli_query($conn ,"SET NAMES utf8");
10. $sql = "select count(*) as total from " .  "table_name";
11. $rec = mysqli_fetch_assoc(mysqli_query( $conn,$sql));
12. echo $rec['total'];
13. mysqli_close($conn);
14. ?>

複製代碼

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. V+ f2 b% K0 r1 P: g9 g當php 7.2.24  connect to mysql server,出現 :

1. PHP Fatal error:  Uncaught Error: Call to undefined function mysqli_connect() in /test/connectmysql8.php:9
2. Stack trace:
3. #0 {main}
4.   thrown in /test/connectmysql8.php on line 9
6. Fatal error: Uncaught Error: Call to undefined function mysqli_connect() in /test/connectmysql8.php:9
7. Stack trace:
8. #0 {main}
9.   thrown in /test/connectmysql8.php on line 9

複製代碼

這是版本相依的問題,只要 yum install php-mysqlnd  或 yum install php-mysqli 即可
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2 S* C  N8 N8 o[Warning] [MY-013242] [Server] --character-set-server: 'utf8' is currently an alias for the character set UTF8MB3, but will be an alias for UTF8MB4 in a future release. Please consider using UTF8MB4 in order to be unambiguous.
8 E8 Q9 B. ~& h' f7 `說明: 千萬不能照它建議用"UTF8MB4",否則無法成功啟動
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(2)
(1064) You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'system>0' at line 1
/ s2 U+ L# S- p/ q( NSELECT COUNT(*) FROM common_usergroup WHERE type='special' and system>0

(1064) You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'groups = '' AND starttime<=1532077291 AND (endtime>=1532077291 OR endtime=0) ORD' at line 1
. [4 e% [$ ^2 I) S! GSELECT * FROM forum_announcement WHERE type!=2 AND groups = '' AND starttime<=1532077291 AND (endtime>=1532077291 OR endtime=0) ORDER BY displayorder, starttime DESC, id DESC LIMIT 1
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# @, z+ f" u5 q; A+ n4 [6 c因為MySQL 8.0+將system和groups作為了關鍵字，所以不能直接在SQL中將system和groups這兩個詞作為數據庫、數據表、數據表字段中的任意一種使用，如果數據庫名或數據表名或數據表字段名使用了system或groups作為名字，必須使用一對反引號引用起來。寫作`system`或`groups`。

5 P! m2 }7 q- F$ n/ ?$ L+ W6 [第一個錯誤需要找到Discuz!目錄中的source\class\table\table_common_usergroup.php，
+ [3 i. E) w: ^4 y將文件中所有的system全部改成`system`，保存後重新上傳到服務器的相同目錄即可。
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4 k3 R4 j/ ]* E第二個錯誤需要找到Discuz!目錄下中的source\class\table\table_forum_announcement.php，
將文件中所有的groups全部改為`groups`，保存後重新上傳到服務器的相同目錄即可。

如果在MySQL 8+環境下安裝Discuz!，在安裝前需要給install\data\install.sql文件中沒有加引號的所有system逐一添加一對反引號保存重新上傳到服務器的相同目錄，否則也會出現SQL語法錯誤。

9 I( \/ M3 s, r3 s! r! m+ @* @; N為了避免語法錯誤，在寫SQL語句時，一定要為所有的數據庫名、數據表名、數據表字段名全部添加一對反引號，像Discuz!這樣的寫法是很不妥的。
以上參考:   升級到 MySQL 8.0+ 後Discuz! 更新緩存時出現SQL語法錯誤
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