[FLINK-1919] Add HCatOutputFormat for Tuple data types

• Type: New Feature
• Status: Closed
• Priority: Minor
• Resolution: Abandoned
• Component/s: API / DataSet
• Labels: starter
• Assignee: James Cao
• Reporter: Fabian Hueske
• Created: 21/Apr/15 13:40
• Updated: 27/Apr/20 11:50
• Resolved: 27/Apr/20 11:50

Description

It would be good to have an OutputFormat that can write data to HCatalog tables.

The Hadoop `HCatOutputFormat` expects `HCatRecord` objects and writes these to HCatalog tables. We can do the same thing, by creating these `HCatRecord` object with a Map function that precedes a `HadoopOutputFormat` that wraps the Hadoop `HCatOutputFormat`.

Better support for Flink Tuples can be added by implementing a custom `HCatOutputFormat` that also depends on the Hadoop `HCatOutputFormat` but internally converts Flink Tuples to `HCatRecords`. This would also include to check if the schema of the HCatalog table and the Flink tuples match. For data types other than tuples, the OutputFormat could either require a preceding Map function that converts to `HCatRecords` or let users specify a MapFunction and invoke that internally.

We have already a Flink `HCatInputFormat` which does this in the reverse directions, i.e., it emits Flink Tuples from HCatalog tables.