[wp-trac] [WordPress Trac] #57072: WordPress 6.1 uses wrong database collation

[WordPress Trac]

#57072: WordPress 6.1 uses wrong database collation
--------------------------+-----------------------------
 Reporter:  Krstarica     |      Owner:  (none)
     Type:  defect (bug)  |     Status:  new
 Priority:  normal        |  Milestone:  Awaiting Review
Component:  Database      |    Version:  6.1
 Severity:  normal        |   Keywords:
  Focuses:                |
--------------------------+-----------------------------
 After upgrade to WordPress 6.1 some plugins started reporting "WordPress
 database error Illegal mix of collations (utf8mb4_unicode_520_ci,IMPLICIT)
 and (utf8mb4_unicode_ci,IMPLICIT)". See:
 https://wordpress.org/support/topic/database-error-after-upgrade-to-
 wordpress-6-1/

 It seems that WordPress 6.1 wrongly detects database collation. This is
 probably related to #54841.

 Database section of the Site Health page (/wp-admin/site-
 health.php?tab=debug) displays:
 {{{
 Database charset        utf8mb4
 Database collation      utf8mb4_unicode_520_ci
 }}}
 Eariler versions displayed correct one:
 {{{
 Database charset        utf8mb4
 Database collation      utf8mb4_unicode_ci
 }}}

 Database collation should be utf8mb4_unicode_ci per server and database
 configuration:

 {{{
 MariaDB [(none)]> SHOW VARIABLES LIKE '%_server' ;
 +----------------------+--------------------+
 | Variable_name        | Value              |
 +----------------------+--------------------+
 | character_set_server | utf8mb4            |
 | collation_server     | utf8mb4_unicode_ci |
 +----------------------+--------------------+
 2 rows in set (0.002 sec)

 MariaDB [(none)]> USE wordpress;
 Database changed

 MariaDB [wordpress]> SELECT @@character_set_database,
 @@collation_database;
 +--------------------------+----------------------+
 | @@character_set_database | @@collation_database |
 +--------------------------+----------------------+
 | utf8mb4                  | utf8mb4_unicode_ci   |
 +--------------------------+----------------------+
 1 row in set (0.000 sec)
 }}}

 Server version: 10.6.10-MariaDB-log

 Having {{{define('DB_COLLATE', '');}}} in wp-config.php.

 Using {{{define( 'DB_COLLATE', 'utf8mb4_unicode_ci' );}}} did not fix the
 issue, nor changed collation information in Database section of the Site
 Health page.

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/57072>
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