diff --git a/src/backend/optimizer/util/pathnode.c b/src/backend/optimizer/util/pathnode.c index 0ac73984d2..66afbd93ac 100644 --- a/src/backend/optimizer/util/pathnode.c +++ b/src/backend/optimizer/util/pathnode.c @@ -778,41 +807,30 @@ add_partial_path(RelOptInfo *parent_rel, Path *new_path) /* Unless pathkeys are incompable, keep just one of the two paths. */ if (keyscmp != PATHKEYS_DIFFERENT) { - if (new_path->total_cost > old_path->total_cost * STD_FUZZ_FACTOR) - { - /* New path costs more; keep it only if pathkeys are better. */ - if (keyscmp != PATHKEYS_BETTER1) - accept_new = false; - } - else if (old_path->total_cost > new_path->total_cost - * STD_FUZZ_FACTOR) + PathCostComparison costcmp; + + /* + * Do a fuzzy cost comparison with standard fuzziness limit. + */ + costcmp = compare_path_costs_fuzzily(new_path, old_path, + STD_FUZZ_FACTOR); + + if (costcmp == COSTS_BETTER1) { - /* Old path costs more; keep it only if pathkeys are better. */ - if (keyscmp != PATHKEYS_BETTER2) + if (keyscmp == PATHKEYS_BETTER1) remove_old = true; } - else if (keyscmp == PATHKEYS_BETTER1) + else if (costcmp == COSTS_BETTER2) { - /* Costs are about the same, new path has better pathkeys. */ - remove_old = true; - } - else if (keyscmp == PATHKEYS_BETTER2) - { - /* Costs are about the same, old path has better pathkeys. */ - accept_new = false; - } - else if (old_path->total_cost > new_path->total_cost * 1.0000000001) - { - /* Pathkeys are the same, and the old path costs more. */ - remove_old = true; + if (keyscmp == PATHKEYS_BETTER2) + accept_new = false; } - else + else if (costcmp == COSTS_EQUAL) { - /* - * Pathkeys are the same, and new path isn't materially - * cheaper. - */ - accept_new = false; + if (keyscmp == PATHKEYS_BETTER1) + remove_old = true; + else if (keyscmp == PATHKEYS_BETTER2) + accept_new = false; } }