diff options
Diffstat (limited to 'src/include')
| -rw-r--r-- | src/include/optimizer/restrictinfo.h | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/src/include/optimizer/restrictinfo.h b/src/include/optimizer/restrictinfo.h index 1b42c832c59..fe03a8ecd34 100644 --- a/src/include/optimizer/restrictinfo.h +++ b/src/include/optimizer/restrictinfo.h @@ -48,4 +48,35 @@ extern bool join_clause_is_movable_into(RestrictInfo *rinfo, Relids currentrelids, Relids current_and_outer); +/* + * clause_sides_match_join + * Determine whether a join clause is of the right form to use in this join. + * + * We already know that the clause is a binary opclause referencing only the + * rels in the current join. The point here is to check whether it has the + * form "outerrel_expr op innerrel_expr" or "innerrel_expr op outerrel_expr", + * rather than mixing outer and inner vars on either side. If it matches, + * we set the transient flag outer_is_left to identify which side is which. + */ +static inline bool +clause_sides_match_join(RestrictInfo *rinfo, Relids outerrelids, + Relids innerrelids) +{ + if (bms_is_subset(rinfo->left_relids, outerrelids) && + bms_is_subset(rinfo->right_relids, innerrelids)) + { + /* lefthand side is outer */ + rinfo->outer_is_left = true; + return true; + } + else if (bms_is_subset(rinfo->left_relids, innerrelids) && + bms_is_subset(rinfo->right_relids, outerrelids)) + { + /* righthand side is outer */ + rinfo->outer_is_left = false; + return true; + } + return false; /* no good for these input relations */ +} + #endif /* RESTRICTINFO_H */ |