I'm having trouble getting a custom module to install and update successfully. I'd like to examine the database for the modules update_N numbers. Is that possible? If it is, where do I look for it?
They're in key/value storage, which in the database would be the
key_value table. Look for entries with a
collection of system.schema, and a
name matching the machine name of the module you're interested in.
Through the API, it's a bit easier:
$current_version = drupal_get_installed_schema_version('name_of_module');
There is another possibility as pointed in the documentation
You could use drush and run the following command:
drush php-eval "echo drupal_get_installed_schema_version('module_name');"
to find the last applied update hook for a specific module.