Known issues in Iceberg

Known issues identified in the September 18, 2026 release

There are no new known issues identified in this release.

Known issues identified before the September 18, 2026 release

CDPD-100780: Materialized view rebuild fails when stored using the Iceberg storage format

Materialized view rebuild operations fail when the materialized view is stored using the Iceberg storage format. This failure occurs due to a defect in Hive during materialized view rebuilds, during which the rebuild process fails but leaves behind a stale lock entry in the MATERIALIZATION_REBUILD_LOCKS table. As a result, subsequent rebuild attempts fail because the existing lock entry prevents new rebuild operations from proceeding.

Instead of running the alter materialized view mat1; statement, drop and recreate the materialized view using the following command:

drop materialized view mat1;
create materialized view mat1 stored by iceberg stored as orc tblproperties ('format-version'='1') as
select tbl_ice.b, tbl_ice.c from tbl_ice where tbl_ice.c > 52;

Apache Jira: HIVE-29436

CDPD-101214: Semantic error in MERGE statements when using backticks with restricted keywords as column names

Hive fails to run MERGE statements with backticks by using restricted keywords as column names. The query displays a SemanticException error during parsing, preventing successful execution of the MERGE operation.

Avoid using restricted keywords as column names, even when enclosed in backticks.

CDPD-101742: Hive Iceberg snapshot expiration fails for ORC LZ4/LZO tables

Hive fails to run queries on Iceberg tables stored in ORC format with LZ4 or LZO compression when LLAP cache is enabled. The failure results in an OWN_TASK_FAILURE status and vertex failures due to an UnsupportedOperationException error during ORC decompression. The snapshot expiration functionality itself works as expected and is not impacted.

For Iceberg tables, disable vectorization by using hive.vectorized.execution.enabled=false.

DWX-14163: Limitations reading Iceberg tables in Avro file format from Impala

The Avro, Impala, and Iceberg specifications describe some limitations related to Avro, and those limitations exist in Cloudera. In addition to these, the DECIMAL type is not supported in this release.

None.

DWX-23400: Impala Iceberg DELETE statements hang when tuple cache is enabled

When running a DELETE statement on an Iceberg table, the Impala query might hang and remain in a RUNNING state indefinitely. This issue occurs due to a logic error in the tuple cache that prevents specific join builds from closing correctly during union operations.

Disable the tuple cache for the specific session or query by running the following command:

SET ENABLE_TUPLE_CACHE=false;

Apache Jira: IMPALA-14951