diff options
Diffstat (limited to 'src/include/nodes/relation.h')
| -rw-r--r-- | src/include/nodes/relation.h | 47 |
1 files changed, 37 insertions, 10 deletions
diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h index aa6217d031..1d490fc17b 100644 --- a/src/include/nodes/relation.h +++ b/src/include/nodes/relation.h @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/nodes/relation.h,v 1.121 2005/11/26 22:14:57 tgl Exp $ + * $PostgreSQL: pgsql/src/include/nodes/relation.h,v 1.122 2005/12/20 02:30:36 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -97,6 +97,8 @@ typedef struct PlannerInfo List *full_join_clauses; /* list of RestrictInfos for full * outer join clauses */ + List *oj_info_list; /* list of OuterJoinInfos */ + List *in_info_list; /* list of InClauseInfos */ List *query_pathkeys; /* desired pathkeys for query_planner(), and @@ -201,10 +203,6 @@ typedef struct PlannerInfo * participates (only used for base rels) * baserestrictcost - Estimated cost of evaluating the baserestrictinfo * clauses at a single tuple (only used for base rels) - * outerjoinset - For a base rel: if the rel appears within the nullable - * side of an outer join, the set of all relids - * participating in the highest such outer join; else NULL. - * Otherwise, unused. * joininfo - List of RestrictInfo nodes, containing info about each * join clause in which this relation participates * index_outer_relids - only used for base rels; set of outer relids @@ -228,10 +226,6 @@ typedef struct PlannerInfo * We store baserestrictcost in the RelOptInfo (for base relations) because * we know we will need it at least once (to price the sequential scan) * and may need it multiple times to price index scans. - * - * outerjoinset is used to ensure correct placement of WHERE clauses that - * apply to outer-joined relations; we must not apply such WHERE clauses - * until after the outer join is performed. *---------- */ typedef enum RelOptKind @@ -277,7 +271,6 @@ typedef struct RelOptInfo List *baserestrictinfo; /* RestrictInfo structures (if base * rel) */ QualCost baserestrictcost; /* cost of evaluating the above */ - Relids outerjoinset; /* set of base relids */ List *joininfo; /* RestrictInfo structures for join clauses * involving this rel */ @@ -831,6 +824,40 @@ typedef struct InnerIndexscanInfo } InnerIndexscanInfo; /* + * Outer join info. + * + * One-sided outer joins constrain the order of joining partially but not + * completely. We flatten such joins into the planner's top-level list of + * relations to join, but record information about each outer join in an + * OuterJoinInfo struct. These structs are kept in the PlannerInfo node's + * oj_info_list. + * + * min_lefthand and min_righthand are the sets of base relids that must be + * available on each side when performing the outer join. lhs_strict is + * true if the outer join's condition cannot succeed when the LHS variables + * are all NULL (this means that the outer join can commute with upper-level + * outer joins even if it appears in their RHS). We don't bother to set + * lhs_strict for FULL JOINs, however. + * + * It is not valid for either min_lefthand or min_righthand to be empty sets; + * if they were, this would break the logic that enforces join order. + * + * Note: OuterJoinInfo directly represents only LEFT JOIN and FULL JOIN; + * RIGHT JOIN is handled by switching the inputs to make it a LEFT JOIN. + * We make an OuterJoinInfo for FULL JOINs even though there is no flexibility + * of planning for them, because this simplifies make_join_rel()'s API. + */ + +typedef struct OuterJoinInfo +{ + NodeTag type; + Relids min_lefthand; /* base relids in minimum LHS for join */ + Relids min_righthand; /* base relids in minimum RHS for join */ + bool is_full_join; /* it's a FULL OUTER JOIN */ + bool lhs_strict; /* joinclause is strict for some LHS rel */ +} OuterJoinInfo; + +/* * IN clause info. * * When we convert top-level IN quals into join operations, we must restrict |