Nezih Yigitbasi created PARQUET-152:
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Summary: Encoding issue with fixed length byte arrays
Key: PARQUET-152
URL: https://issues.apache.org/jira/browse/PARQUET-152
Project: Parquet
Issue Type: Bug
Reporter: Nezih Yigitbasi
Priority: Minor
While running some tests against the master branch I noticed that when writing
a fixed length byte array and the array's size is > dictionaryPageSize (in my
test it was 512), the encoding falls back to DELTA_BYTE_ARRAY as seen below:
Dec 17, 2014 3:41:10 PM INFO: parquet.hadoop.ColumnChunkPageWriteStore: written
12,125B for [flba_field] FIXED_LEN_BYTE_ARRAY: 5,000 values, 1,710B raw, 1,710B
comp, 5 pages, encodings: [DELTA_BYTE_ARRAY]
But then read fails with the following exception:
Caused by: parquet.io.ParquetDecodingException: Encoding DELTA_BYTE_ARRAY is
only supported for type BINARY
at parquet.column.Encoding$7.getValuesReader(Encoding.java:193)
at
parquet.column.impl.ColumnReaderImpl.initDataReader(ColumnReaderImpl.java:534)
at
parquet.column.impl.ColumnReaderImpl.readPageV2(ColumnReaderImpl.java:574)
at
parquet.column.impl.ColumnReaderImpl.access$400(ColumnReaderImpl.java:54)
at
parquet.column.impl.ColumnReaderImpl$3.visit(ColumnReaderImpl.java:518)
at
parquet.column.impl.ColumnReaderImpl$3.visit(ColumnReaderImpl.java:510)
at parquet.column.page.DataPageV2.accept(DataPageV2.java:123)
at
parquet.column.impl.ColumnReaderImpl.readPage(ColumnReaderImpl.java:510)
at
parquet.column.impl.ColumnReaderImpl.checkRead(ColumnReaderImpl.java:502)
at
parquet.column.impl.ColumnReaderImpl.consume(ColumnReaderImpl.java:604)
at
parquet.column.impl.ColumnReaderImpl.<init>(ColumnReaderImpl.java:348)
at
parquet.column.impl.ColumnReadStoreImpl.newMemColumnReader(ColumnReadStoreImpl.java:63)
at
parquet.column.impl.ColumnReadStoreImpl.getColumnReader(ColumnReadStoreImpl.java:58)
at
parquet.io.RecordReaderImplementation.<init>(RecordReaderImplementation.java:267)
at parquet.io.MessageColumnIO$1.visit(MessageColumnIO.java:131)
at parquet.io.MessageColumnIO$1.visit(MessageColumnIO.java:96)
at
parquet.filter2.compat.FilterCompat$NoOpFilter.accept(FilterCompat.java:136)
at parquet.io.MessageColumnIO.getRecordReader(MessageColumnIO.java:96)
at
parquet.hadoop.InternalParquetRecordReader.checkRead(InternalParquetRecordReader.java:129)
at
parquet.hadoop.InternalParquetRecordReader.nextKeyValue(InternalParquetRecordReader.java:198)
... 16 more
When the array's size is < dictionaryPageSize, RLE_DICTIONARY encoding is used
and read works fine:
Dec 17, 2014 3:39:50 PM INFO: parquet.hadoop.ColumnChunkPageWriteStore: written
50B for [flba_field] FIXED_LEN_BYTE_ARRAY: 5,000 values, 3B raw, 3B comp, 1
pages, encodings: [RLE_DICTIONARY, PLAIN], dic { 1 entries, 8B raw, 1B comp}
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