[jira] [Created] (ARROW-10958) "Nested data conversions not implemented" through glib, but not through pyarrow

[Samay Kapadia (Jira)]

Samay Kapadia created ARROW-10958:
-------------------------------------

             Summary: "Nested data conversions not implemented" through glib, 
but not through pyarrow
                 Key: ARROW-10958
                 URL: https://issues.apache.org/jira/browse/ARROW-10958
             Project: Apache Arrow
          Issue Type: Bug
          Components: GLib
    Affects Versions: 2.0.0
         Environment: macOS Catalina 10.15.7
            Reporter: Samay Kapadia


Hey all,

For some context, I am trying to use Arrow's GLib interface through Julia; I 
have a sense that I can speedup by pandas workflows by using Julia and Apache 
Arrow.

I have a 1.7GB parquet file that can be read in about 20s by using pyarrow's 
parquet reader
{code:java}
pq.read_table(path)
{code}
but I've tried to go the same through the GLib interface in Julia and I'm seeing
{code:java}
[parquet][arrow][file-reader][read-table]: NotImplemented: Nested data 
conversions not implemented for chunked array outputs
{code}
{{Arrow was installed using }}

{{brew install apache-arrow-glib}}

{{and it installed version 2.0.0}}

Here's my Julia code:
{code:java}
using Pkg
Pkg.add("Gtk")
using Gtk.GLib
using Gtk

path = "..." # contains columns that are lists of strings

struct _GParquetArrowFileReader
    parent_instance::Cint
end

const GParquetArrowFileReader = _GParquetArrowFileReaderstruct 
_GParquetArrowFileReaderClass
    parent_class::Cint
end

const GParquetArrowFileReaderClass = _GParquetArrowFileReaderClass

struct _GArrowTable
    parent_instance::Cint
end

const GArrowTable = _GArrowTable

struct _GArrowTableClass
    parent_class::Cint
end

const GArrowTableClass = _GArrowTableClass

function 
parquet_arrow_file_reader_new_path(path::String)::Ptr{GParquetArrowFileReader}
    ret::Ptr{GParquetArrowFileReader} = 0
    GError() do error_check
        ret = ccall(
            (:gparquet_arrow_file_reader_new_path, 
"/usr/local/Cellar/apache-arrow-glib/2.0.0/lib/libparquet-glib.200"), 
            Ptr{GParquetArrowFileReader}, 
            (Ptr{UInt8}, Ptr{Ptr{GError}}), 
            Gtk.bytestring(path), error_check
        )
        ret != 0
    end
    ret
end

function 
parquet_arrow_file_reader_read_table(reader::Ptr{GParquetArrowFileReader})::Ptr{GArrowTable}
    ret::Ptr{GArrowTable} = 0
    GError() do error_check
        ret = ccall(
            (:gparquet_arrow_file_reader_read_table, 
"/usr/local/Cellar/apache-arrow-glib/2.0.0/lib/libparquet-glib.200"), 
            Ptr{GParquetArrowFileReader}, 
            (Ptr{GParquetArrowFileReader}, Ptr{Ptr{GError}}), 
            reader, error_check
        )
        ret != 0
    end
    ret
end

reader = parquet_arrow_file_reader_new_path(path)
tbl = parquet_arrow_file_reader_read_table(reader)
{code}
Am I doing something wrong or is there a behavior discrepancy between pyarrow 
and glib?



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