# BigInt (64bit) identifiers

Nextcloud uses big integers to store identifiers and auto-increment keys in the database. Because changing columns on huge tables can take quite a while (up to hours or days) depending on the number of files in the Nextcloud instance, this migration on the filecache and activity table has to be triggered manually by a console command.

The command can safely be executed. It will show a success message when there is nothing to do:

    sudo -E -u www-data php occ db:convert-filecache-bigint
    All tables already up to date!

or otherwise ask for confirmation, before performing the heavy actions:

    sudo -E -u www-data php occ db:convert-filecache-bigint
    This can take up to hours, depending on the number of files in your instance!
    Continue with the conversion (y/n)? [n]

to suppress the confirmation message append `--no-interaction` to the argument list:

    sudo -E -u www-data php occ db:convert-filecache-bigint --no-interaction

> **提示**
>
> Similar to a normal update, you should shutdown your Apache or nginx server or enable maintenance mode before running the command to avoid issues with your sync clients.