[
https://issues.apache.org/jira/browse/HIVE-6405?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13907369#comment-13907369
]
Sushanth Sowmyan commented on HIVE-6405:
----------------------------------------
Given that we added on HIVE-6465 for ql grammar work, and there is still
additional work on hive and hcatalog required to make append on HCatalog work
with dynamic partitioning, I'm going to treat this bug as an epic task, and
create a new jira for the specific implementation of the append feature on
HCatalog.
(Also, the qa failures here are because this patch would have worked only after
HIVE-6406 was merged in, which it wasn't at the time the tests ran)
> 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.
--
This message was sent by Atlassian JIRA
(v6.1.5#6160)
