Hello,
I have started using a firebase service, push notifications.
When users were less, it was not causing any problems but once it is started to increase users around 1 lakh -- then when I send push notifications it causes my Drupal site to went down and showing error as below:
PDOException: SQLSTATE[HY000] [2002] Connection refused in lock_may_be_available() (line 167 of /var/www/html/includes/lock.inc).
I am using dedicated server with 16GB RAM, 8 core CPU
Anyone there to guide me?