1. Google Merchant.
Whenever you experience the error: Maximum execution time of 30 seconds exceeded it possibly takes to long for a respond on the server. This is caused by a large feed combined with a server setting which generates the time-out in Magento. Whenever you experience this Error we highly recommend that you contact your hosting business to fix this issue for you.
Step 1 : Open php.ini;
Step 2 : Modify the value of “max_execution_time” to a greater value say 600;
Step 3: Restart Server
Method 2 (Recommended):
Add “set_time_limit(600)” in your code, where the input parameter is the max execution time, and 0 means unlimited.