[iceberg] Refuse nanosecond timestamps while Iceberg metadata is enabled - #9455
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[iceberg] Refuse nanosecond timestamps while Iceberg metadata is enabled#9455plusplusjiajia wants to merge 5 commits into
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Purpose
IcebergDataField emits timestamp_ns for timestamp columns of precision 7 and above, but Paimon writes those columns as Parquet INT96, which Iceberg reads as a microsecond zoned timestamp. The metadata and the data files therefore disagree, and nothing reports it — an Iceberg reader silently returns wrong values.
This refuses such a column while metadata.iceberg.storage is enabled, next to the existing geospatial rule in SchemaValidation, so it applies wherever a schema is validated: creating a table, altering one, and enabling Iceberg metadata on a table that already has such a column.
This is a behaviour change: a table with a nanosecond timestamp column mirrors today, producing metadata no Iceberg reader can use. Lower the precision to 6, or disable metadata.iceberg.storage