diff options
Diffstat (limited to 'src/include/nodes/relation.h')
| -rw-r--r-- | src/include/nodes/relation.h | 56 |
1 files changed, 21 insertions, 35 deletions
diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h index d3fb2231f1..a21debe02f 100644 --- a/src/include/nodes/relation.h +++ b/src/include/nodes/relation.h @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $Id: relation.h,v 1.75 2003/01/12 22:35:29 tgl Exp $ + * $Id: relation.h,v 1.76 2003/01/15 19:35:44 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -50,7 +50,7 @@ typedef struct QualCost * Per-relation information for planning/optimization * * For planning purposes, a "base rel" is either a plain relation (a table) - * or the output of a sub-SELECT that appears in the range table. + * or the output of a sub-SELECT or function that appears in the range table. * In either case it is uniquely identified by an RT index. A "joinrel" * is the joining of two or more base rels. A joinrel is identified by * the set of RT indexes for its component baserels. We create RelOptInfo @@ -63,14 +63,10 @@ typedef struct QualCost * * We also have "other rels", which are like base rels in that they refer to * single RT indexes; but they are not part of the join tree, and are stored - * in other_rel_list not base_rel_list. An otherrel is created for each - * join RTE as an aid in processing Vars that refer to the join's outputs, - * but it serves no other purpose in planning. It is important not to - * confuse this otherrel with the joinrel that represents the matching set - * of base relations. - * - * A second category of otherrels are those made for child relations of an - * inheritance scan (SELECT FROM foo*). The parent table's RTE and + * in other_rel_list not base_rel_list. + * + * Currently the only kind of otherrels are those made for child relations + * of an inheritance scan (SELECT FROM foo*). The parent table's RTE and * corresponding baserel represent the whole result of the inheritance scan. * The planner creates separate RTEs and associated RelOptInfos for each child * table (including the parent table, in its capacity as a member of the @@ -80,6 +76,10 @@ typedef struct QualCost * the inheritance set; then the parent baserel is given an Append plan * comprising the best plans for the individual child tables. * + * At one time we also made otherrels to represent join RTEs, for use in + * handling join alias Vars. Currently this is not needed because all join + * alias Vars are expanded to non-aliased form during preprocess_expression. + * * Parts of this data structure are specific to various scan and join * mechanisms. It didn't seem worth creating new node types for them. * @@ -114,15 +114,7 @@ typedef struct QualCost * set_base_rel_pathlist processes the object. * * For otherrels that are inheritance children, these fields are filled - * in just as for a baserel. In otherrels for join RTEs, these fields - * are empty --- the only useful field of a join otherrel is its - * outerjoinset. - * - * If the relation is a join relation it will have these fields set: - * - * joinrti - RT index of corresponding JOIN RTE, if any; 0 if none - * joinrteids - List of RT indexes of JOIN RTEs included in this join - * (including joinrti) + * in just as for a baserel. * * The presence of the remaining fields depends on the restrictions * and joins that the relation participates in: @@ -135,8 +127,7 @@ typedef struct QualCost * outerjoinset - For a base rel: if the rel appears within the nullable * side of an outer join, the list of all relids * participating in the highest such outer join; else NIL. - * For a join otherrel: the list of all baserel relids - * syntactically within the join. Otherwise, unused. + * Otherwise, unused. * joininfo - List of JoinInfo nodes, containing info about each join * clause in which this relation participates * index_outer_relids - only used for base rels; list of outer relids @@ -170,7 +161,6 @@ typedef enum RelOptKind { RELOPT_BASEREL, RELOPT_JOINREL, - RELOPT_OTHER_JOIN_REL, RELOPT_OTHER_CHILD_REL } RelOptKind; @@ -202,10 +192,6 @@ typedef struct RelOptInfo double tuples; struct Plan *subplan; /* if subquery */ - /* information about a join rel (not set for base rels!) */ - Index joinrti; - List *joinrteids; - /* used by various scans and joins: */ List *baserestrictinfo; /* RestrictInfo structures (if * base rel) */ @@ -276,15 +262,6 @@ typedef struct IndexOptInfo /* - * A Var is considered to belong to a relation if it's either from one - * of the actual base rels making up the relation, or it's a join alias - * var that is included in the relation. - */ -#define VARISRELMEMBER(varno,rel) (intMember((varno), (rel)->relids) || \ - intMember((varno), (rel)->joinrteids)) - - -/* * PathKeys * * The sort ordering of a path is represented by a list of sublists of @@ -583,6 +560,15 @@ typedef struct RestrictInfo QualCost eval_cost; /* eval cost of clause; -1 if not yet set */ Selectivity this_selec; /* selectivity; -1 if not yet set */ + /* + * If the clause looks useful for joining --- that is, it is a binary + * opclause with nonoverlapping sets of relids referenced in the left + * and right sides --- then these two fields are set to lists of the + * referenced relids. Otherwise they are both NIL. + */ + List *left_relids; /* relids in left side of join clause */ + List *right_relids; /* relids in right side of join clause */ + /* valid if clause is mergejoinable, else InvalidOid: */ Oid mergejoinoperator; /* copy of clause operator */ Oid left_sortop; /* leftside sortop needed for mergejoin */ |