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 009841d9dd3..e2967d1cf61 100644 --- a/src/backend/optimizer/plan/planmain.c +++ b/src/backend/optimizer/plan/planmain.c @@ -365,7 +365,7 @@ 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 3a812877d62..e062cabf7a2 100644 --- a/src/backend/optimizer/plan/planner.c +++ b/src/backend/optimizer/plan/planner.c @@ -1134,11 +1134,14 @@ 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 |