we are push notification providers and using GCM to deliver push notifications. but from last few days we are facing issues "Mysql server gone away 2006" , we have tried everything like Max_execution_time, MAX_PACKET_ALLOWED.. etc server variable. also we have added set_time_limit(0) to head of cron.
Server Environment:
CENTOS:6
RAM : 96 GB
CPU: 20 Core
DATABASE: MYsql
PHP: 5.6
Framework: Codeigniter
also using pconnect False for Codeigniter database connection. Main problem in when we are accessing database using direct function call its working fine. but when are using threw the cron (PHP SCRIPT) or ajax its giving mysql server gone error . may be its causes we are calling multiple function in cron in line but the call is synchronous means second function dependent of result of first function. at last we are sending push to Google.