lcspinter opened a new pull request, #3570:
URL: https://github.com/apache/hive/pull/3570
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### What changes were proposed in this pull request?
Raise exception when trying to convert hive table to iceberg if the hive
table contains CHAR or VARCHAR columns.
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### Why are the changes needed?
Previously CHAR and VARCHAR columns were mapped to STRING columns on the
iceberg side since iceberg doesn't have support for those.
CHAR and VARCHAR types are fixed-length meaning that the values can be
shorter than the specified length, and the remaining characters are padded with
spaces. These spaces are trimmed during comparison.
When a table is migrated to iceberg the CHAR columns are read as a STRING on
the iceberg side, therefore the whole content of the record is considered
important. When running a filter against these columns we would need to add the
whole content of the record, including white spaces. This can cause confusion
since the same query run on a hive and iceberg table can return different
results.
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### Does this PR introduce _any_ user-facing change?
When running the iceberg migration command, an exception is raised if the
source table contains CHAR or VARCHAR columns. As a workaround, the dataset of
the source table should be converted to string.
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### How was this patch tested?
Unit test
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