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https://issues.apache.org/jira/browse/HIVE-6405?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Sushanth Sowmyan updated HIVE-6405:
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Attachment: (was: HIVE-6405.patch)
> Support append feature for HCatalog
> -----------------------------------
>
> Key: HIVE-6405
> URL: https://issues.apache.org/jira/browse/HIVE-6405
> Project: Hive
> Issue Type: Bug
> Components: HCatalog, Metastore, Query Processor, Thrift API
> Reporter: Sushanth Sowmyan
> Assignee: Sushanth Sowmyan
>
> HCatalog currently treats all tables as "immutable" - i.e. all tables and
> partitions can be written to only once, and not appended. The nuances of what
> this means is as follows:
> * A non-partitioned table can be written to, and data in it is never updated
> from then on unless you drop and recreate.
> * A partitioned table may support "appending" of a sort in a manner by
> adding new partitions to the table, but once written, the partitions
> themselves cannot have any new data added to them.
> Hive, on the other hand, does allow us to "INSERT INTO" into a table, thus
> allowing us append semantics. There is benefit to both of these models, and
> so, our goal is as follows:
> a) Introduce a notion of an immutable table, wherein all tables are not
> immutable by default, and have this be a table property. If this property is
> set for a table, and we attempt to write to a table that already has data (or
> a partition), disallow "INSERT INTO" into it from hive. This property being
> set will allow hive to mimic HCatalog's current immutable-table property.
> (I'm going to create a separate sub-task to cover this bit, and focus on the
> HCatalog-side on this jira)
> b) As long as that flag is not set, HCatalog should be changed to allow
> appends into it as well, and not simply error out if data already exists in a
> table.
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