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https://issues.apache.org/jira/browse/HIVE-16452?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16008703#comment-16008703
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Lefty Leverenz commented on HIVE-16452:
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Does this need to be documented in the wiki?
> Database UUID for metastore DB
> ------------------------------
>
> Key: HIVE-16452
> URL: https://issues.apache.org/jira/browse/HIVE-16452
> Project: Hive
> Issue Type: New Feature
> Components: Metastore
> Reporter: Vihang Karajgaonkar
> Assignee: Vihang Karajgaonkar
>
> In cloud environments it is possible that a same database instance is used as
> the long running metadata persistence layer and multiple HMS access this
> database. These HMS instances could be running the same time or in case of
> transient workloads come up on an on-demand basis. HMS is used by multiple
> projects in the Hadoop eco-system as the de-facto metadata keeper for various
> SQL engines on the cluster. Currently, there is no way to uniquely identify
> the database instance which is backing the HMS. For example, if there are two
> instances of HMS running on top of same metastore DB, there is no way to
> identify that data received from both the metastore clients is coming from
> the same database. Similarly, if there in case of transient workloads
> multiple HMS services come up and go, a external application which is
> fetching data from a HMS has no way to identify that these multiple instances
> of HMS are in fact returning the same data.
> We can potentially use the combination of javax.jdo.option.ConnectionURL,
> javax.jdo.option.ConnectionDriverName configuration of each HMS instance but
> this is approach may not be very robust. If the database is migrated to
> another server for some reason the ConnectionURL can change. Having a UUID in
> the metastore DB which can be queried using a Thrift API can help solve this
> problem. This way any application talking to multiple HMS instances can
> recognize if the data is coming the same backing database.
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