[英]Is it feasible to perform a cross database federated query in redshift?
while cross database queries (in ra3 node based clusters) and federated queries individually seem to work, together it seems that they won't work.虽然跨数据库查询(在基于 ra3 节点的集群中)和联合查询单独似乎可以工作,但它们似乎一起不起作用。 I am most probably missing something, hence the question.我很可能遗漏了一些东西,因此提出了这个问题。 Below are the details:以下是详细信息:
select count(1) from ext_mdb.Table2; select count(1) 来自 ext_mdb.Table2;
select count(1) from RSDB1.ext_mdb.Table2;来自 RSDB1.ext_mdb.Table2 的 select 计数(1); # this also works # 这也有效
select count(1) from RSDB1.ext_mdb.Table2;来自 RSDB1.ext_mdb.Table2 的 select 计数(1); # this doesn't from RSDB2 # 这不是来自 RSDB2
ERROR: Relation Table2 does not exist in the database.错误:数据库中不存在关系表 2。
It seems like a limitation for cross database queries in redshift at the moment from what I understood reading this: https://docs.aws.amazon.com/redshift/latest/dg/cross-database_limitation.html从我的理解来看,这似乎是红移中跨数据库查询的限制:
where it says它说的地方
Amazon Redshift doesn't support query catalog objects on AWS Glue or federated databases. Amazon Redshift 不支持在 AWS Glue 或联合数据库上查询目录对象。 To query these objects, first create external schemas that refer to those external data sources in each database.要查询这些对象,首先创建引用每个数据库中的那些外部数据源的外部模式。
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