Thank you very much for your answer. But I ??m very sorry, I still do n??t 
understand. Can you elaborate more?

------------------ ???????? ------------------
??????:&nbsp;"David Mollitor"<;;
????????:&nbsp;2020??1??15??(??????) ????11:01

????:&nbsp;Re: Why Hive uses MetaStore??

In the beginning, hive was a command line tool.&nbsp; All the heavy lifting 
happened on the user's local box.&nbsp; If a user wanted to execute hive from 
their laptop, or a server, it always needs access to the list of available 
tables (and their schemas and their locations), otherwise every SQL script 
would have to start with the table definition of every table involved in the 
query. Today, it's primarily HiveServer2 and there can be many instances in the 
same environment.&nbsp; They all need to share table meta data.

It is also helpful to keep statistics on every table.&nbsp; Table statistics 
are key in generating efficient query plans.&nbsp; If yue statistics are not 
persisted anywhere, it would be lost after every query.

Since Hive2, the role of the metastore has only expanded to include, for 
example, a global locking system to protect tables from concurrent access.

On Wed, Jan 15, 2020, 9:51 AM qq <; wrote:

&nbsp; &nbsp; &nbsp; Why Hive uses MetaStore??Is there a related JIRA?
&nbsp; &nbsp; &nbsp;
&nbsp;I am looking forward to your reply??

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