Binary statistics are invalid if buffers are reused

[asfimport]

BinaryStatistics does not copy the min or max binary objects, so if the buffers are shared (as they usually are in MapReduce), then the statistics are incorrect.

Reporter: Thomas White / @tomwhite

Related issues:

• Binary column statistics error when reuse byte[] among rows (duplicates)
• DictionaryValuesWriter dictionaries are corrupted by user changes. (is related to)

_{Note: This issue was originally created as PARQUET-326. Please see the migration documentation for further details.}

[asfimport]

Thomas White / @tomwhite:
See PR #236.