Stamatis Zampetakis created HIVE-29525:
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Summary: Iceberg partitioned columns are not reflected by
RelOptHiveTable
Key: HIVE-29525
URL: https://issues.apache.org/jira/browse/HIVE-29525
Project: Hive
Issue Type: Bug
Components: CBO
Reporter: Stamatis Zampetakis
Iceberg partitioned columns are not reflected by RelOptHiveTable and the
respective data-structures (hivePartitionCols and hivePartitionColsMap) are
always empty. RelOptHiveTable is used in various places during the CBO planning
phase so any logic that depends on partitioning information is not kicking in
and all Iceberg tables are treated as unpartitioned.
Depending on the context where the partitioning information is used different
issues may arise. For instance, selectivity estimation is computed differently
if the predicate is over a partitioning column (see
[FilterSelectivityEstimator|https://github.com/apache/hive/blob/931d4bb62b26de699240c816df439e00644e3dcb/ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/stats/FilterSelectivityEstimator.java#L105])
so the absence of partitioning information can have a direct impact on
cardinality (row count) estimations and affect join order.
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