upgradation of concrete 5.6 to 5.8
Now I have upgrade it to concrete 5.8 or latest version.
In site approximately 2-3 cache data and in database is 3 Gb.
So please give idea how to upgrade it, with affecting the database.
what is correct approach to do it.
1- You can use the migration tool that will allow you to migrate most core data: pages, users, files, attributes... it will not migrate anything non-core so custom blocks and coding, packages from the marketplace, all that will not be migrated. You can find the information and links to the tools here:http://andrewembler.com/2015/11/upgrade-concrete5-sites-57-using-ou...
2- You rebuild the site from scratch
I suggest using both approaches. Use the migration tool to get all the content, pages and cor stuff to the new site and then build a new theme with updated functionality from scratch
because database is must impotent it content approximately 3 gb.