On 08.07.21 20:17, Alvaro Herrera wrote:
diff --git a/src/backend/rewrite/rewriteSearchCycle.c b/src/backend/rewrite/rewriteSearchCycle.c index 599fe8e735..c50ebdba24 100644 --- a/src/backend/rewrite/rewriteSearchCycle.c +++ b/src/backend/rewrite/rewriteSearchCycle.c @@ -307,8 +307,8 @@ rewriteSearchAndCycle(CommonTableExpr *cte) list_nth_oid(cte->ctecolcollations, i), 0); tle = makeTargetEntry((Expr *) var, i + 1, strVal(list_nth(cte->ctecolnames, i)), false); - tle->resorigtbl = castNode(TargetEntry, list_nth(rte1->subquery->targetList, i))->resorigtbl; - tle->resorigcol = castNode(TargetEntry, list_nth(rte1->subquery->targetList, i))->resorigcol; + tle->resorigtbl = list_nth_node(TargetEntry, rte1->subquery->targetList, i)->resorigtbl; + tle->resorigcol = list_nth_node(TargetEntry, rte1->subquery->targetList, i)->resorigcol;This seems a bit surprising to me. I mean, clearly we trust our List implementation to be so good that we can just fetch the same node twice, one for each member of the same struct, and the compiler will optimize everything so that it's a single access to the n'th list entry. Is this true? I would have expected there to be a single fetch of the struct, followed by an access of each of the two struct members.
Lists are arrays now internally, so accessing an element by number is pretty cheap.
