query_agent_size_files = """
    WITH values AS (
    SELECT
    4096/(ceil(pg_settings.setting::numeric/1024/1024)) AS segment_parts_count,
    setting::bigint AS segment_size,
    ('x' || substring(pg_stat_archiver.last_archived_wal from 9 for 8))::bit(32)::int AS last_wal_div,
    ('x' || substring(pg_stat_archiver.last_archived_wal from 17 for 8))::bit(32)::int AS last_wal_mod,
    CASE WHEN pg_is_in_recovery() THEN NULL ELSE
    ('x' || substring(pg_{1}_name(pg_current_{0}()) from 9 for 8))::bit(32)::int END AS current_wal_div,
    CASE WHEN pg_is_in_recovery() THEN NULL ELSE
    ('x' || substring(pg_{1}_name(pg_current_{0}()) from 17 for 8))::bit(32)::int END AS current_wal_mod
    FROM pg_settings, pg_stat_archiver
    WHERE pg_settings.name = 'wal_segment_size')
    greatest(coalesce(((segment_parts_count - last_wal_mod) + ((current_wal_div - last_wal_div - 1) * segment_parts_count) + current_wal_mod - 1) * segment_size, 0), 0)::bigint AS size_files
    FROM values;
    """