diff options
Diffstat (limited to 'src/backend/optimizer')
| -rw-r--r-- | src/backend/optimizer/path/allpaths.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c index 905250b3325..6cc6966b060 100644 --- a/src/backend/optimizer/path/allpaths.c +++ b/src/backend/optimizer/path/allpaths.c @@ -1891,7 +1891,17 @@ generate_orderedappend_paths(PlannerInfo *root, RelOptInfo *rel, */ if (root->tuple_fraction > 0) { - double path_fraction = (1.0 / root->tuple_fraction); + double path_fraction = root->tuple_fraction; + + /* + * Merge Append considers only live children relations. Dummy + * relations must be filtered out before. + */ + Assert(childrel->rows > 0); + + /* Convert absolute limit to a path fraction */ + if (path_fraction >= 1.0) + path_fraction /= childrel->rows; cheapest_fractional = get_cheapest_fractional_path_for_pathkeys(childrel->pathlist, |