def compare_pool_config(user_pool_config, running_pool_details):
    '''
    Compare user input config pool details with current running pool details
    '''

    delta = {}
    filter_keys = ['pg_num', 'pg_placement_num', 'size',
                   'pg_autoscale_mode', 'target_size_ratio',
                   'crush_rule']
    for key in filter_keys:
        if (str(running_pool_details[key]) != user_pool_config[key]['value'] and  # noqa: E501
                user_pool_config[key]['value']):
            delta[key] = user_pool_config[key]

    if (running_pool_details['application'] !=
            user_pool_config['application']['value'] and
            user_pool_config['application']['value']):
        delta['application'] = {}
        delta['application']['new_application'] = user_pool_config['application']['value']  # noqa: E501
        # to be improved (for update_pools()...)
        delta['application']['value'] = delta['application']['new_application']
        delta['application']['old_application'] = running_pool_details['application']  # noqa: E501

    return delta

    Compare user input config pool details with current running pool details
    
library/ceph_pool.py