shachibista opened a new issue, #365:
URL: https://github.com/apache/arrow-go/issues/365
### Describe the enhancement requested
Field level metadata on arrow schema is not persisted into the parquet
files.
Here's a test script:
```golang
package main
import (
"fmt"
"os"
"github.com/apache/arrow-go/v18/arrow"
"github.com/apache/arrow-go/v18/arrow/array"
"github.com/apache/arrow-go/v18/arrow/memory"
"github.com/apache/arrow-go/v18/parquet"
"github.com/apache/arrow-go/v18/parquet/compress"
"github.com/apache/arrow-go/v18/parquet/pqarrow"
)
func main() {
schema := arrow.NewSchema([]arrow.Field{
{Name: "id", Type: arrow.BinaryTypes.Binary, Metadata:
arrow.MetadataFrom(map[string]string{
"external_type": "uuid",
})},
{Name: "name", Type: arrow.BinaryTypes.String},
}, nil)
out, err := os.Create("test.parquet")
if err != nil {
fmt.Println(err)
return
}
wr, err := pqarrow.NewFileWriter(
schema,
out,
parquet.NewWriterProperties(
parquet.WithCompression(compress.Codecs.Snappy),
parquet.WithDataPageVersion(parquet.DataPageV2),
parquet.WithVersion(parquet.V2_LATEST),
),
pqarrow.DefaultWriterProps(),
)
if err != nil {
fmt.Println(err)
return
}
defer wr.Close()
rb := array.NewRecordBuilder(memory.DefaultAllocator, schema)
defer rb.Release()
rb.Field(0).AppendNull()
rb.Field(1).AppendNull()
wr.Write(rb.NewRecord())
}
```
```python
import pyarrow.parquet as pq
table = pq.read_table("test.parquet")
field = table.schema.field("id")
print(field.metadata) # prints None
```
### Component(s)
Parquet
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