Re: [HACKERS] Compiler warning in costsize.c

On Mon, Apr 10, 2017 at 9:05 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> I wonder if we shouldn't just do
>
>         RangeTblEntry *rte PG_USED_FOR_ASSERTS_ONLY;
>         ListCell   *lc;
>
>         /* Should only be applied to base relations that are subqueries */
>         Assert(rel->relid > 0);
> -#ifdef USE_ASSERT_CHECKING
>         rte = planner_rt_fetch(rel->relid, root);
>         Assert(rte->rtekind == RTE_SUBQUERY);
> -#endif
>
> and eat the "useless" calculation of rte.

That works as well. Now this code really has been written so as we
don't want to do this useless computation for non-Assert builds,
that's why I did not suggest it. But as it does just a list_nth call,
that's not really costly... And other code paths dealing with the cost
do it as well.
-- 
Michael