[ARROW-6076] [C++][Parquet] RecordReader::Reset logic is inefficient for small reads

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: C++
• External issue URL: https://github.com/apache/arrow/issues/16826
• Assignee: Unassigned
• Reporter: Wes McKinney
• Created: 31/Jul/19 02:12
• Updated: 11/Jan/23 07:44

Description

We have a unit test

https://github.com/apache/arrow/blob/master/cpp/src/parquet/arrow/arrow-reader-writer-test.cc#L933

that reads 1 record at a time from a Parquet-Arrow column reader. There is logic on RecordReader that advances the definition/repetition levels based on consumed data from previous records, but this is inefficient for this case:

https://github.com/apache/arrow/blob/master/cpp/src/parquet/column_reader.cc#L1011

This should be refactored to not require this copying, or at least to only "shift" the levels occasionally