[ARROW-16749] [Go] Bug when converting from Arrow to Parquet from null array

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 9.0.0
• Fix Version/s: 9.0.0
• Component/s: Go
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/20276
• Assignee: Alexandre Crayssac
• Reporter: Alexandre Crayssac
• Created: 03/Jun/22 12:57
• Updated: 11/Jan/23 11:46
• Resolved: 10/Jun/22 17:58

Description

Hello world,

When converting from Arrow to Parquet it looks like there is a bug with arrays of type arrow.NULL. Here is a snippet of code to reproduce the bug:

 

package main

import (
	"fmt"
	"log"
	"os"

	"github.com/apache/arrow/go/v9/arrow"
	"github.com/apache/arrow/go/v9/arrow/array"
	"github.com/apache/arrow/go/v9/arrow/memory"
	"github.com/apache/arrow/go/v9/parquet/pqarrow"
)

const n = 10

func run() error {
	schema := arrow.NewSchema(
		[]arrow.Field{
			{Name: "f1", Type: arrow.Null, Nullable: true},
		},
		nil,
	)

	rb := array.NewRecordBuilder(memory.DefaultAllocator, schema)
	defer rb.Release()

	for i := 0; i < n; i++ {
		rb.Field(0).(*array.NullBuilder).AppendNull()
	}

	rec := rb.NewRecord()
	defer rec.Release()

	for i, col := range rec.Columns() {
		fmt.Printf("column[%d] %q: %v\n", i, rec.ColumnName(i), col)
	}

	f, err := os.Create("output.parquet")
	if err != nil {
		return err
	}
	defer f.Close()

	w, err := pqarrow.NewFileWriter(rec.Schema(), f, nil, pqarrow.DefaultWriterProps())
	if err != nil {
		return err
	}
	defer w.Close()

	err = w.Write(rec)
	if err != nil {
		return err
	}

	return nil
}

func main() {
	if err := run(); err != nil {
		log.Fatal(err)
	}
} 

Issue Links

• links to: GitHub Pull Request #13310