[ 
https://issues.apache.org/jira/browse/HIVE-18685?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16384079#comment-16384079
 ] 

Vihang Karajgaonkar commented on HIVE-18685:
--------------------------------------------

Thanks [~alangates] for taking this up. I think this would be a good addition. 
I went through the doc attached and all the comments above and I have some 
questions:

bq. It will not be possible to address a table as catalog.database.table.  
Which catalog you are connected to will be determine when the session is 
started and is immutable initially.
If you cannot address table using catalog.database.table how would a user be 
able to issue cross catalog queries. eg. join between tables across catalogs?

Regarding catalog location,
Does it mean that all databases/tables created under a catalog default to a 
location of catalog? As a corollary to this, if a user gives a location which 
doesn't make sense with respect to the catalog's location (catalogs being the 
logical separation of systems) should we have hooks which can allow us to 
enforce the location of the catalogs?

Should the catalog have a owner as well? Who is allowed to create/drop the 
catalog?

> Add catalogs to metastore
> -------------------------
>
>                 Key: HIVE-18685
>                 URL: https://issues.apache.org/jira/browse/HIVE-18685
>             Project: Hive
>          Issue Type: New Feature
>          Components: Metastore, Parser, Security, SQL
>    Affects Versions: 3.0.0
>            Reporter: Alan Gates
>            Assignee: Alan Gates
>            Priority: Major
>         Attachments: HMS Catalog Design Doc.pdf
>
>
> SQL supports two levels of namespaces, called in the spec catalogs and 
> schemas (with schema being equivalent to Hive's database).  I propose to add 
> the upper level of catalog.  The attached design doc covers the use cases, 
> requirements, and brief discussion of how it will be implemented in a 
> backwards compatible way.



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)

Reply via email to