Redshift drop有依赖关系的表

今天开发需要删除AWS Redshift的一个归档表，但是直接drop发生了如下报错，发现有其他对象依赖这个表，导致无法直接删除，但是报错没有直接显示是什么对象依赖它，可能是有视图，外键等约束

analyticsprod=# DROP TABLE IF EXISTS facts.auto_events_bk_20170223;
ERROR: cannot drop table auto_events_bk_20170223 because other objects depend on it
HINT: Use DROP ... CASCADE to drop the dependent objects too.

通过\d+ auto_events_bk_20170223 查看表结构，发现并没有其他表的外键约束，所以排除；
然后通过\dv+命令在schema：facts下查看视图，但是发现没有任何view存在，但是view可能存在其他schema或db,
那么问题来了,如何在整个数据库中找到与这个表有依赖的的view?

这里AWS Redshift已经给我们提供了一个好的方法,参考链接：https://docs.aws.amazon.com/redshift/latest/dg/r_DROP_TABLE.html

创建一个视图find_depend:

create view find_depend as
select distinct c_p.oid as tbloid,
n_p.nspname as schemaname, c_p.relname as name,
n_c.nspname as refbyschemaname, c_c.relname as refbyname,
c_c.oid as viewoid
from pg_catalog.pg_class c_p
join pg_catalog.pg_depend d_p
on c_p.relfilenode = d_p.refobjid
join pg_catalog.pg_depend d_c
on d_p.objid = d_c.objid
join pg_catalog.pg_class c_c
on d_c.refobjid = c_c.relfilenode
left outer join pg_namespace n_p
on c_p.relnamespace = n_p.oid
left outer join pg_namespace n_c
on c_c.relnamespace = n_c.oid
where d_c.deptype = 'i'::"char"
and c_c.relkind = 'v'::"char";

查询视图找到与表auto_events_bk_20170223相关的view:

analyticsprod=# select * from facts.find_depend where schemaname='facts' and name not in ('find_depend') order by name;
tbloid | schemaname |          name           | refbyschemaname | &nb
b60
sp;refbyname  | viewoid
--------+------------+-------------------------+-----------------+-------------+---------
879566 | facts      | auto_events_bk_20170223 | public          | map_routes2 |  965969
879566 | facts      | auto_events_bk_20170223 | public          | map_routes  |  966155
879566 | facts      | auto_events_bk_20170223 | public          | map_edges   | 1019697
(3 rows)

analyticsprod=# set search_path to public;

analyticsprod=# \dv
List of relations
schema |         name          | type | owner
--------+-----------------------+------+-------
public | map_edges             | view | fengw
public | map_edges_group       | view | fengw
public | map_route_edges_group | view | fengw
public | map_routes            | view | fengw
public | map_routes2           | view | fengw
public | map_routes_group      | view | fengw
(6 rows)

最后如果判断这些相关的view没有用的话，可以通过命令drop table auto_events_bk_20170223 cascade删除表，包括视图一同删除。