GP数据库中表结构查询的方法：
select d.nspname
,obj_description(d.oid)
,c.relname
,obj_description(c.oid)
,a.attnum
,a.attname
,e.data_type
,col_description(c.oid,a.attum)
,e.is_nullable
,case where e.data_type ~ ‘character‘
then e.character_maximum_length|| ‘‘
where e.data_type ~ ‘numeric‘
then (((‘(‘||e.numeric_precision)||‘,‘)||e.numeric_scale)||‘)‘
else ‘‘
end
from pg_class
left join pg_acctribute a
on a.atttypid = t.oid
join pg_namespace d
on d.oid = c.relnamespace
and d.nspname not like ‘pg_%‘
join information_schema.cloumns e
on c.relname = e.table_name::name
and a.attnum = e.ordinal_position
and e.table_schema::name = d.nspname
where c.relname !~ ‘pg|prt‘
and a.attnum > 0
order by d.nspname
,c.relname
,a.attnum
;
GP数据库占用表空间
select pg_size_pretty(pg_relation_size(‘schema_name.table_name‘));
select pg_size_pretty(pg_database_size(‘db_name‘));
原文：http://6666613.blog.51cto.com/6656613/1676882