Re: About the stability of COPY BINARY data

On 11/6/24 08:20, Dominique Devienne wrote:
>>From https://www.postgresql.org/docs/current/sql-copy.html:
> |> binary-format file is less portable across machine architectures
> and PostgreSQL versions
>
> In my experience, the binary encoding of binding/resultset/copy is
> endian neutral (network byte order), so what is the less portable
> across machine architectures that warning about?
>
> Also, does the code for per-type _send() and _recv() functions really change
> across versions of PostgreSQL? How common are instances of such
> changes across versions? Any examples of such backward-incompatible
> changes, in the past?
>
> The binary data contains OIDs, but if sticking to built-in types,
> which OIDs are unlikely to change across versions?
>
> I'm obviously storing COPY BINARY data (we have lots of bytea
> columns), and I wonder how bad it is long term, and across PostgreSQL
> versions.

If I where to hazard a guess this plays a part:

https://www.postgresql.org/docs/current/sql-copy.html

"To determine the appropriate binary format for the actual tuple data
you should consult the PostgreSQL source, in particular the *send and
*recv functions for each column's data type (typically these functions
are found in the src/backend/utils/adt/ directory of the source
distribution)."

>
> Thanks for any insights, --DD
>
>

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com