Re: Schema variables - new implementation for Postgres 15

On Fri, Aug 11, 2023 at 05:55:26PM +0200, Dmitry Dolgov wrote:
>
> Another confusing example was this one at the end of set_session_variable:
>
> + /*
> + * XXX While unlikely, an error here is possible. It wouldn't leak memory
> + * as the allocated chunk has already been correctly assigned to the
> + * session variable, but would contradict this function contract, which is
> + * that this function should either succeed or leave the current value
> + * untouched.
> + */
> + elog(DEBUG1, "session variable \"%s.%s\" (oid:%u) has new value",
> + get_namespace_name(get_session_variable_namespace(svar->varid)),
> + get_session_variable_name(svar->varid),
> + svar->varid);
>
> It's not clear, which exactly error you're talking about, it's the last
> instruction in the function.

FTR I think I'm the one that changed that. The error I was talking about is
elog() itself (in case of OOM for instance), or even one of the get_* call, if
running with log_level <= DEBUG1. It's clearly really unlikely but still
possible, thus this comment which also tries to explain why this elog() is not
done earlier.