diff options
Diffstat (limited to 'src/backend/optimizer')
| -rw-r--r-- | src/backend/optimizer/plan/planmain.c | 2 | ||||
| -rw-r--r-- | src/backend/optimizer/plan/planner.c | 7 |
2 files changed, 6 insertions, 3 deletions
diff --git a/src/backend/optimizer/plan/planmain.c b/src/backend/optimizer/plan/planmain.c index 16d3af32ed0..6647640b385 100644 --- a/src/backend/optimizer/plan/planmain.c +++ b/src/backend/optimizer/plan/planmain.c @@ -356,7 +356,7 @@ query_planner(PlannerInfo *root, List *tlist, * can be divided by the number of tuples. */ if (tuple_fraction >= 1.0) - tuple_fraction /= final_rel->rows; + tuple_fraction /= clamp_row_est(final_rel->rows); } /* diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c index 0bb8d20d8e6..300fbcec163 100644 --- a/src/backend/optimizer/plan/planner.c +++ b/src/backend/optimizer/plan/planner.c @@ -1295,11 +1295,14 @@ grouping_planner(PlannerInfo *root, double tuple_fraction) /* * Extract rowcount and width estimates for possible use in grouping * decisions. Beware here of the possibility that - * cheapest_path->parent is NULL (ie, there is no FROM clause). + * cheapest_path->parent is NULL (ie, there is no FROM clause). Also, + * if the final rel has been proven dummy, its rows estimate will be + * zero; clamp it to one to avoid zero-divide in subsequent + * calculations. */ if (cheapest_path->parent) { - path_rows = cheapest_path->parent->rows; + path_rows = clamp_row_est(cheapest_path->parent->rows); path_width = cheapest_path->parent->width; } else |