diff options
Diffstat (limited to 'src/include/nodes/relation.h')
| -rw-r--r-- | src/include/nodes/relation.h | 33 |
1 files changed, 6 insertions, 27 deletions
diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h index f00d1becc7..e8e20d202b 100644 --- a/src/include/nodes/relation.h +++ b/src/include/nodes/relation.h @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/nodes/relation.h,v 1.168 2009/02/06 23:43:24 tgl Exp $ + * $PostgreSQL: pgsql/src/include/nodes/relation.h,v 1.169 2009/02/25 03:30:37 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -1076,30 +1076,6 @@ typedef struct InnerIndexscanInfo } InnerIndexscanInfo; /* - * "Flattened SubLinks" - * - * When we pull an IN or EXISTS SubLink up into the parent query, the - * join conditions extracted from the IN/EXISTS clause need to be specially - * treated in distribute_qual_to_rels processing. We handle this by - * wrapping such expressions in a FlattenedSubLink node that identifies - * the join they come from. The FlattenedSubLink node is discarded after - * distribute_qual_to_rels, having served its purpose. - * - * Although the planner treats this as an expression node type, it is not - * recognized by the parser or executor, so we declare it here rather than - * in primnodes.h. - */ - -typedef struct FlattenedSubLink -{ - Expr xpr; - JoinType jointype; /* must be JOIN_SEMI or JOIN_ANTI */ - Relids lefthand; /* base relids treated as syntactic LHS */ - Relids righthand; /* base relids syntactically within RHS */ - Expr *quals; /* join quals (in explicit-AND format) */ -} FlattenedSubLink; - -/* * Placeholder node for an expression to be evaluated below the top level * of a plan tree. This is used during planning to represent the contained * expression. At the end of the planning process it is replaced by either @@ -1171,8 +1147,11 @@ typedef struct PlaceHolderVar * For purposes of join selectivity estimation, we create transient * SpecialJoinInfo structures for regular inner joins; so it is possible * to have jointype == JOIN_INNER in such a structure, even though this is - * not allowed within join_info_list. Note that lhs_strict, delay_upper_joins, - * and join_quals are not set meaningfully for such structs. + * not allowed within join_info_list. We also create transient + * SpecialJoinInfos with jointype == JOIN_INNER for outer joins, since for + * cost estimation purposes it is sometimes useful to know the join size under + * plain innerjoin semantics. Note that lhs_strict, delay_upper_joins, and + * join_quals are not set meaningfully within such structs. */ typedef struct SpecialJoinInfo |