Hi all,

Following up on this thread. I've done some preliminary analysis and wanted to 
share findings, and also offer to take on FLINK-37094.

Flink 2.0 compatibility (FLINK-37094)
--------------------------------------

I compiled the external connector against Flink 2.0.0 and cataloged all the 
breakages. There are ~100 compilation errors across 13 files, falling into 
these categories:

- Legacy Table API removed (TableSource, TableSink, TableSourceFactory, etc.) - 
4 files
- UniqueConstraint removed from table.api.constraints - 7 files including the 
HiveShim interface
- StreamingFileSink/BucketsBuilder removed - HiveTableSink.java
- ManagedTableFactory/ManagedTableListener removed - HiveCatalog, 
HiveDynamicTableFactory
- CatalogLock/RequireCatalogLock removed - HiveCatalog, HiveCatalogLock
- flink-hadoop-compatibility artifact dropped the _2.12 Scala suffix

I'd like to take on FLINK-37094 and submit a PR for these fixes. This would be 
a prerequisite for any further work on the external connector, including Hive 4 
support.

Hive 4 compatibility
---------------------

I also compiled against hive-exec:4.0.0 and the results are encouraging - only 
5 compilation errors across 8 files, all in the SQL parser/planner layer (class 
relocations and removals in Hive 4). Notably, the deprecated HMS Thrift APIs 
(HIVE-26537) that we listed as a known breaking change in the original proposal 
do not actually affect this connector - the IMetaStoreClient interface is 
unchanged in Hive 4.

Next steps
----------

I'm ready to start on the FLINK-37094 fixes immediately. Would a committer be 
willing to review a PR for the Flink 2.0 adaptation? Once that's in, the Hive 4 
changes are relatively small on top.

Thanks,
Jayesh

On 4/8/26, 3:23 PM, "Lalwani, Jayesh" <[email protected] 
<mailto:[email protected]>> wrote:


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Hi everyone,


We'd like to propose adding Apache Hive 4.x support to the externalized Hive 
connector (https://github.com/apache/flink-connector-hive 
<https://github.com/apache/flink-connector-hive>).


Motivation
----------


Apache Hive 4.0.0 was released in March 2024, with 4.1.0 following later that 
year. Hive 4 introduces significant changes including Iceberg integration, HMS 
Thrift-over-HTTP transport, JWT authentication, Calcite 1.25, and standalone 
metastore improvements. The Flink Hive connector currently supports only Hive 
2.3.x and 3.1.x.


There is an existing JIRA for this (FLINK-35515) but no prior discussion on the 
mailing list and no active work.


We are aware that the Hive connector externalization is still in progress — 
FLINK-30064 remains open, FLINK-37094 (adapting to Flink 2.0 API changes) is 
unassigned, and the external repo has not yet published a release. We are 
willing to help with these items as part of this effort.


Scope
-----


We would target Flink 2.x only. Since the Hive connector has already been 
removed from core Flink's master branch (FLINK-33786), and the external repo 
needs Flink 2.0 API adaptation work regardless (FLINK-37094), it makes sense to 
do Hive 4 support on top of a Flink 2.x-compatible connector rather than 
backporting to 1.20.


The work would include:


1. Help resolve FLINK-37094 (adapt the external connector to Flink 2.0 API 
changes) as a prerequisite
2. Add a HiveShimV400 following the existing shim pattern in 
org.apache.flink.table.catalog.hive.client
3. Add a flink-sql-connector-hive-4.0.0 bundled JAR module
4. Update HiveShimLoader to recognize Hive 4.x versions
5. Handle known breaking changes:
- Deprecated HMS Thrift APIs (HIVE-26537)
- Thrift-over-HTTP transport support (HIVE-21456)
- Calcite version alignment (Hive 4 uses 1.25, Flink uses a shaded version)
- Dependency updates (Hadoop 3.3.6 baseline)
6. Update documentation and tests


Questions for the community
---------------------------


- Would this require a FLIP, or is the existing FLINK-35515 JIRA sufficient 
given that this follows the established shim pattern?
- Are there any concerns about the Calcite version conflict between Hive 4 and 
Flink's shaded Calcite?
- Is there a committer willing to shepherd this work through review?


We'd appreciate feedback on the approach.


Thanks,
Jayesh Lalwani



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