In the beginning, hive was a command line tool. All the heavy lifting happened on the user's local box. 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. They all need to share table meta data.
It is also helpful to keep statistics on every table. Table statistics are key in generating efficient query plans. 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 <987626...@qq.com> wrote: > Hello: > Why Hive uses MetaStore？Is there a related JIRA? > > thinks. > I am looking forward to your reply！ >
