Re: Make COPY format extendable: Extract COPY TO format implementations - Mailing list pgsql-hackers

On Wed, Dec 6, 2023 at 2:19 PM Sutou Kouhei <kou@clear-code.com> wrote:
>
> Hi,
>
> In <CAEG8a3Jf7kPV3ez5OHu-pFGscKfVyd9KkubMF199etkfz=EPRg@mail.gmail.com>
>   "Re: Make COPY format extendable: Extract COPY TO format implementations" on Wed, 6 Dec 2023 11:18:35 +0800,
>   Junwang Zhao <zhjwpku@gmail.com> wrote:
>
> > For the modern formats(parquet, orc, avro, etc.), will they be
> > implemented as extensions or in core?
>
> I think that they should be implemented as extensions
> because they will depend of external libraries and may not
> use C. For example, C++ will be used for Apache Parquet
> because the official Apache Parquet C++ implementation
> exists but the C implementation doesn't.
>
> (I can implement an extension for Apache Parquet after we
> complete this feature. I'll implement an extension for
> Apache Arrow with the official Apache Arrow C++
> implementation. And it's easy that we convert Apache Arrow
> data to Apache Parquet with the official Apache Parquet
> implementation.)
>
> > The patch looks good except for a pair of extra curly braces.
>
> Thanks for the review! I attach the v2 patch that removes
> extra curly braces for "if (isnull)".
>
For the extra curly braces, I mean the following code block in
CopyToFormatBinaryStart:

+ {        <-- I thought this is useless?
+ /* Generate header for a binary copy */
+ int32 tmp;
+
+ /* Signature */
+ CopySendData(cstate, BinarySignature, 11);
+ /* Flags field */
+ tmp = 0;
+ CopySendInt32(cstate, tmp);
+ /* No header extension */
+ tmp = 0;
+ CopySendInt32(cstate, tmp);
+ }

>
> Thanks,
> --
> kou



--
Regards
Junwang Zhao