diff options
Diffstat (limited to 'src/backend/optimizer/plan/initsplan.c')
| -rw-r--r-- | src/backend/optimizer/plan/initsplan.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c index c5998b9e2de..04a399ee13c 100644 --- a/src/backend/optimizer/plan/initsplan.c +++ b/src/backend/optimizer/plan/initsplan.c @@ -649,6 +649,9 @@ deconstruct_jointree(PlannerInfo *root) Assert(root->parse->jointree != NULL && IsA(root->parse->jointree, FromExpr)); + /* this is filled as we scan the jointree */ + root->nullable_baserels = NULL; + result = deconstruct_recurse(root, (Node *) root->parse->jointree, false, &qualscope, &inner_join_rels, &postponed_qual_list); @@ -790,6 +793,7 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join, left_inners, right_inners, nonnullable_rels, + nullable_rels, ojscope; List *leftjoinlist, *rightjoinlist; @@ -823,6 +827,8 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join, *inner_join_rels = *qualscope; /* Inner join adds no restrictions for quals */ nonnullable_rels = NULL; + /* and it doesn't force anything to null, either */ + nullable_rels = NULL; break; case JOIN_LEFT: case JOIN_ANTI: @@ -837,6 +843,7 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join, *qualscope = bms_union(leftids, rightids); *inner_join_rels = bms_union(left_inners, right_inners); nonnullable_rels = leftids; + nullable_rels = rightids; break; case JOIN_SEMI: leftjoinlist = deconstruct_recurse(root, j->larg, @@ -851,6 +858,13 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join, *inner_join_rels = bms_union(left_inners, right_inners); /* Semi join adds no restrictions for quals */ nonnullable_rels = NULL; + + /* + * Theoretically, a semijoin would null the RHS; but since the + * RHS can't be accessed above the join, this is immaterial + * and we needn't account for it. + */ + nullable_rels = NULL; break; case JOIN_FULL: leftjoinlist = deconstruct_recurse(root, j->larg, @@ -865,16 +879,22 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join, *inner_join_rels = bms_union(left_inners, right_inners); /* each side is both outer and inner */ nonnullable_rels = *qualscope; + nullable_rels = *qualscope; break; default: /* JOIN_RIGHT was eliminated during reduce_outer_joins() */ elog(ERROR, "unrecognized join type: %d", (int) j->jointype); nonnullable_rels = NULL; /* keep compiler quiet */ + nullable_rels = NULL; leftjoinlist = rightjoinlist = NIL; break; } + /* Report all rels that will be nulled anywhere in the jointree */ + root->nullable_baserels = bms_add_members(root->nullable_baserels, + nullable_rels); + /* * For an OJ, form the SpecialJoinInfo now, because we need the OJ's * semantic scope (ojscope) to pass to distribute_qual_to_rels. But |