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BIT_PACKING is written by default when Definition or Repetition levels are empty

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#3,307 6 comments 0 reactions 0 assignees View on GitHub

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Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
48/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
java

Research direction

Start by locating DevNullValuesWriter and inspecting its getEncoding() implementation, then trace how that value reaches the column metadata and DataPageHeader. Confirm that empty repetition and definition levels no longer produce the deprecated BIT_PACKED encoding and instead use RLE.

Written by the indexing model from the issue text.

Description

Type: bug

As discussed in https://github.com/apache/arrow/discussions/47113 , this package is writing the deprecated BIT_PACKING encoding to the column metadata and the DataPageHeader. This is only seems to happens when rep/def levels are empty. I think this is where it's happening:

public class DevNullValuesWriter extends ValuesWriter {
  ....
  public Encoding getEncoding() {
    return BIT_PACKED;
  }
}

Wouldn't it make sense to just return RLE?

I've seen this in parquet-java 1.15.1 and Overture Maps files using 1.13.1.

Dominant language
Java
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Merged PRs (30d)
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