When changing some custom field name it will apply on back-end and you can see the new changed name in product details panel.
but after visiting the fornt-end the new name for the field does not showing and its still the old name.
the only solution that we found its a necessary action to open each product pages in panel and save the products again to apply & showing the new custom field name on front-end.
Example: Define the new string with parent named X, after changing the X on custom field to Y, the website is showing the X not Y, and it need to open the each product and save again to apply the new name on frontpage.
That's may be a Cache issue. Please clear the cache of your site and check. If you have enabled System Cache Plugin in your site then please disable it and check.
All the system cache plugins was disabled, also we did clear all the cache items.!!!! :-\
Is there any sql command to update all the products with new changes?
Have your tried the Repair & Optimize option at phpMyAdmin?