diff options
Diffstat (limited to 'src/backend')
| -rw-r--r-- | src/backend/optimizer/plan/analyzejoins.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/src/backend/optimizer/plan/analyzejoins.c b/src/backend/optimizer/plan/analyzejoins.c index 0dfefd71f21..f79bc4430c1 100644 --- a/src/backend/optimizer/plan/analyzejoins.c +++ b/src/backend/optimizer/plan/analyzejoins.c @@ -183,6 +183,14 @@ join_is_removable(PlannerInfo *root, SpecialJoinInfo *sjinfo) if (!bms_get_singleton_member(sjinfo->min_righthand, &innerrelid)) return false; + /* + * Never try to eliminate a left join to the query result rel. Although + * the case is syntactically impossible in standard SQL, MERGE will build + * a join tree that looks exactly like that. + */ + if (innerrelid == root->parse->resultRelation) + return false; + innerrel = find_base_rel(root, innerrelid); /* |