PolarDB这个语句不走列存，为什么？

PolarDB这个语句不走列存，为什么？ 加上orderby那列 语义会发生变化查询结果不一样了SELECT
DISTINCT p.products_id,
p.products_name AS products_name_m,
p.products_url_name,
p.cas_no,
p.seller_count,
p.price_trend_count,
p.produce_count,
p.features_flag,
p.information_flag
FROM
t_e_products p
INNER JOIN t_e_all_produce_seller_activity sdt ON sdt.products_id = p.products_id
AND IFNULL(sdt.delflag, '') <> '1'
INNER JOIN t_e_casno_relation rel ON rel.cas_no_target = p.cas_no
AND rel.cas_no = '56-81-5'
AND IFNULL(rel.delflag, '') != '1'
INNER JOIN t_zy_price_index pi ON pi.product_id = p.products_id
AND IFNULL(pi.delflag, '') != '1'
WHERE
p.information_flag = '1'
AND IFNULL(p.delflag, '') != '1'
ORDER BY
pi.update_date DESC,
1 = 1
LIMIT
5