[jira] [Assigned] (HIVE-17466) Metastore API to list unique partition-key-value combinations

["Mithun Radhakrishnan (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HIVE-17466?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Mithun Radhakrishnan reassigned HIVE-17466:
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> Metastore API to list unique partition-key-value combinations
> -------------------------------------------------------------
>
>                 Key: HIVE-17466
>                 URL: https://issues.apache.org/jira/browse/HIVE-17466
>             Project: Hive
>          Issue Type: New Feature
>          Components: Metastore
>    Affects Versions: 2.2.0, 3.0.0
>            Reporter: Mithun Radhakrishnan
>            Assignee: Thiruvel Thirumoolan
>
> Raising this on behalf of [~thiruvel], who wrote this initially as part of a tangential "data-discovery" system.
> Programs like Apache Oozie, Apache Falcon (or Yahoo GDM), etc. launch workflows based on the availability of table/partitions. Partitions are currently discovered by listing partitions using (what boils down to) {{HiveMetaStoreClient.listPartitions()}}. This can be slow and cumbersome, given that {{Partition}} objects are heavyweight and carry redundant information. The alternative is to use partition-names, which will need client-side parsing to extract part-key values.
> When checking which hourly partitions for a particular day have been published already, it would be preferable to have an API that pushed down part-key extraction into the {{RawStore}} layer, and returned key-values as the result. This would be similar to how {{SELECT DISTINCT part_key FROM my_table;}} would run, but at the {{HiveMetaStoreClient}} level.
> Here's what we've been using at Yahoo.



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