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https://issues.apache.org/jira/browse/HIVE-5317?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14615279#comment-14615279
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Paul Fosse commented on HIVE-5317:
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Merge command seems to be needed to do the first use case of the ACID feature.
"Once an hour, a set of inserts and updates (up to 500k rows) for various
dimension tables (eg. customer, inventory, stores) needs to be processed. The
dimension tables have primary keys and are typically bucketed and sorted on
those keys."
Typically we will load the updates to a hive table and just want to merge that
table to the existing dimension. We are either using the old way of doing this
(ingest, reconcile, compact & purge) or we are writing a Python script to
process the updates. But we can't do 500K update statements an hour, so it
doesn't seem the ACID does us any good for this use case until we have merge
> Implement insert, update, and delete in Hive with full ACID support
> -------------------------------------------------------------------
>
> Key: HIVE-5317
> URL: https://issues.apache.org/jira/browse/HIVE-5317
> Project: Hive
> Issue Type: New Feature
> Reporter: Owen O'Malley
> Assignee: Owen O'Malley
> Fix For: 0.14.0
>
> Attachments: InsertUpdatesinHive.pdf
>
>
> Many customers want to be able to insert, update and delete rows from Hive
> tables with full ACID support. The use cases are varied, but the form of the
> queries that should be supported are:
> * INSERT INTO tbl SELECT …
> * INSERT INTO tbl VALUES ...
> * UPDATE tbl SET … WHERE …
> * DELETE FROM tbl WHERE …
> * MERGE INTO tbl USING src ON … WHEN MATCHED THEN ... WHEN NOT MATCHED THEN
> ...
> * SET TRANSACTION LEVEL …
> * BEGIN/END TRANSACTION
> Use Cases
> * Once an hour, a set of inserts and updates (up to 500k rows) for various
> dimension tables (eg. customer, inventory, stores) needs to be processed. The
> dimension tables have primary keys and are typically bucketed and sorted on
> those keys.
> * Once a day a small set (up to 100k rows) of records need to be deleted for
> regulatory compliance.
> * Once an hour a log of transactions is exported from a RDBS and the fact
> tables need to be updated (up to 1m rows) to reflect the new data. The
> transactions are a combination of inserts, updates, and deletes. The table is
> partitioned and bucketed.
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