Re: Schema variables - new implementation for Postgres 15 - Mailing list pgsql-hackers

From Dmitry Dolgov
Subject Re: Schema variables - new implementation for Postgres 15
Date
Msg-id 20230812112003.gkirnqlk4bgf47us@erthalion.local
Whole thread Raw
In response to Re: Schema variables - new implementation for Postgres 15  (Julien Rouhaud <rjuju123@gmail.com>)
Responses Re: Schema variables - new implementation for Postgres 15
List pgsql-hackers
> On Sat, Aug 12, 2023 at 09:28:19AM +0800, Julien Rouhaud wrote:
> 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.

I see, thanks for clarification. Absolutely nitpicking, but the crucial
"that's why this elog is not done earlier" is only assumed in the
comment between the lines, not stated out loud :)



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