Re: meaning of PQresultStatus types

On May 23 11:30, jois(dot)de(dot)vivre(at)gmail(dot)com wrote:
> I'm currently trying to understand how to deal with the return values
> of PGresultStatus in terms of error handling in my application. The
> postgres manual describes the return codes of PGresultStatus as:
>
> PGRES_EMPTY_QUERY: The string sent to the server was empty.
> PGRES_COMMAND_OK: Successful completion of a command returning no data.
> PGRES_TUPLES_OK: Successful completion of a command returning data.
> PGRES_COPY_OUT: Copy Out (from server) data transfer started.
> PGRES_COPY_IN: Copy In (to server) data transfer started.
> PGRES_BAD_RESPONSE: The server's response was not understood.
> PGRES_NONFATAL_ERROR: A nonfatal error (a notice or warning) occurred.
> PGRES_FATAL_ERROR: A fatal error occurred.
>
> My question is, what constitutes a PGRES_FATAL_ERROR or a
> PGRES_BAD_RESPONSE?

AFAIK, at the moment, libpq doesn't return a PGRES_BAD_RESPONSE status
for any operation. (Furthermore, I think there're some situations where
it should do, like in the not understood or incomplete messages in
pqParseInput?() family. I'm also wondering the thoughts of developers
if I'd propose I patch for this.)

To learn more about in which situations libpq turns PGRES_FATAL_ERROR
flag on, you can make a

grep PGRES_FATAL_ERROR -RHn src/interfaces/libpq

call in the PostgreSQL's source directory. (Or better use cscope.)

Regards.