[jira] [Commented] (ARROW-9562) [C++] Append table to existing feather file

[Haejin Choi (Jira)]

    [ 
https://issues.apache.org/jira/browse/ARROW-9562?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17174001#comment-17174001
 ] 

Haejin Choi commented on ARROW-9562:
------------------------------------

[~jorisvandenbossche] Here is my example code

{code:c++}
using namespace std;
using namespace arrow;

void WriteFeather(shared_ptr<Table> table, string path)
{
    // Open a file stream with [append mode]
    shared_ptr<io::FileOutputStream> fos;
    io::FileOutputStream::Open(path, true).Value(&fos);

    // Write the table to file stream
    ipc::feather::WriteTable(*table, fos.get());
}

int main()
{
    shared_ptr<Table> table_1, table_2;

    // read table from CSV
    ReadTableFromCSV(&table_1, "file1.csv");
    ReadTableFromCSV(&table_2, "file2.csv");

    // write feather file
    WriteFeather(table_1, "result.feather");
    WriteFeather(table_2, "result.feather");

    return 0;
}
{code}

I expect that "result.feather" has both "table_1" and "table_2", but It has 
only "table_2"


> [C++] Append table to existing feather file
> -------------------------------------------
>
>                 Key: ARROW-9562
>                 URL: https://issues.apache.org/jira/browse/ARROW-9562
>             Project: Apache Arrow
>          Issue Type: Improvement
>          Components: C++
>            Reporter: Haejin Choi
>            Priority: Major
>              Labels: feather
>
> As far as I know, If a new  table is appended to existing feather file,
> feather::Reader::Read reads only new one not old one. 
> Does this approach not match the purpose of the feather file?



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