[
https://issues.apache.org/jira/browse/SPARK-59853?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
L. C. Hsieh updated SPARK-59853:
--------------------------------
Priority: Minor (was: Major)
> Accept a short last bit-packed run in the vectorized RLE reader
> ---------------------------------------------------------------
>
> Key: SPARK-59853
> URL: https://issues.apache.org/jira/browse/SPARK-59853
> Project: Spark
> Issue Type: Improvement
> Components: SQL
> Affects Versions: 5.0.0
> Reporter: L. C. Hsieh
> Priority: Minor
>
> The Parquet spec requires bit-packed runs in the RLE/bit-packing hybrid
> encoding to be padded to a multiple of 8 values, but some non-compliant
> writers write a last bit-packed run that is shorter than its padding, e.g.
> Polars before https://github.com/pola-rs/polars/pull/13883 (see
> https://github.com/pola-rs/polars/issues/13818, "Spark can't read parquet
> files written by polars").
> The vectorized reader (VectorizedRleValuesReader) rejects such a run, even
> when its bytes cover every value that is read, while the non-vectorized
> reader reads it: parquet-java's RunLengthBitPackingHybridDecoder reads
> min(numGroups * bitWidth, available) bytes. Arrow C++ also accepts it since
> https://github.com/apache/arrow/pull/47992.
> The vectorized reader could accept it the way Arrow does: only for the last
> run of the stream, and only the values fully covered by the remaining bytes,
> so reading past them still fails.
> This came up in the review of SPARK-59832
> (https://github.com/apache/spark/pull/59117), which keeps the existing strict
> behavior.
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
