Errors during Plesk Update: ERROR: Zend_Db_Adapter_Exception: SQLSTATE[HY000] [2002] No such file or directory

Symptoms

• The following errors appear in Plesk during the update:

  PLESK_ERROR: #ERROR: Zend_Db_Adapter_Exception: SQLSTATE[HY000] [2002] No such file or directory (Abstract.php:144)
  ERROR: Uncaught exception ‘PDOException’ with message ‘SQLSTATE[HY000] [2002] No such file or directory’ in /opt/psa/admin/externals/Zend/Db/Adapter/Pdo/Abstract.php:129

• In /var/log/apt/history.log (for Debian and Ubuntu) or /var/log/yum.log (for Centos and RHEL) there are messages about mysql being updated.

Cause

This is a bug PPPM-7903, which will be fixed in the future versions of Plesk.

Resolution

As a workaround perform the following steps:

1. Connect to the server using SSH;
2. Add mysql/mariadb package to the yum/apt exclusion list via CLI:
   For Red Hat based (yum):
   Edit /etc/yum.conf file:

   # cat /etc/yum.conf
   [main]
   . . .
   exclude=<packagename>

   For Debian based (apt-get):

   # apt-mark hold <packagename>

3. Perform a manual mysql/mariadb update: How to upgrade MySQL 5.5 to 5.6/5.7 or MariaDB .5 to 10.0/10.1/10.2 on Linux
4. Remove exclusions which were set on step 2:
   For Red Hat based (yum):
   Edit /etc/yum.conf file:

   # cat /etc/yum.conf
   [main]
   . . .
   #exclude=<packagename>

   For Debian based (apt-get):

   # apt-mark unhold <packagename>