diff options
Diffstat (limited to 'src/backend/optimizer/plan/planner.c')
| -rw-r--r-- | src/backend/optimizer/plan/planner.c | 46 |
1 files changed, 24 insertions, 22 deletions
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c index b55f8380d47..5510a749573 100644 --- a/src/backend/optimizer/plan/planner.c +++ b/src/backend/optimizer/plan/planner.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.123 2002/08/28 20:46:23 momjian Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.124 2002/09/04 20:31:21 momjian Exp $ * *------------------------------------------------------------------------- */ @@ -42,7 +42,7 @@ static Node *pull_up_subqueries(Query *parse, Node *jtnode, - bool below_outer_join); + bool below_outer_join); static bool is_simple_subquery(Query *subquery); static bool has_nullable_targetlist(Query *subquery); static void resolvenew_in_jointree(Node *jtnode, int varno, List *subtlist); @@ -301,16 +301,16 @@ pull_up_subqueries(Query *parse, Node *jtnode, bool below_outer_join) * * If we are inside an outer join, only pull up subqueries whose * targetlists are nullable --- otherwise substituting their tlist - * entries for upper Var references would do the wrong thing - * (the results wouldn't become NULL when they're supposed to). - * XXX This could be improved by generating pseudo-variables for - * such expressions; we'd have to figure out how to get the pseudo- - * variables evaluated at the right place in the modified plan tree. - * Fix it someday. + * entries for upper Var references would do the wrong thing (the + * results wouldn't become NULL when they're supposed to). XXX + * This could be improved by generating pseudo-variables for such + * expressions; we'd have to figure out how to get the pseudo- + * variables evaluated at the right place in the modified plan + * tree. Fix it someday. * * Note: even if the subquery itself is simple enough, we can't pull - * it up if there is a reference to its whole tuple result. Perhaps - * a pseudo-variable is the answer here too. + * it up if there is a reference to its whole tuple result. + * Perhaps a pseudo-variable is the answer here too. */ if (rte->rtekind == RTE_SUBQUERY && is_simple_subquery(subquery) && (!below_outer_join || has_nullable_targetlist(subquery)) && @@ -336,8 +336,8 @@ pull_up_subqueries(Query *parse, Node *jtnode, bool below_outer_join) below_outer_join); /* - * Now make a modifiable copy of the subquery that we can - * run OffsetVarNodes on. + * Now make a modifiable copy of the subquery that we can run + * OffsetVarNodes on. */ subquery = copyObject(subquery); @@ -352,7 +352,8 @@ pull_up_subqueries(Query *parse, Node *jtnode, bool below_outer_join) * Replace all of the top query's references to the subquery's * outputs with copies of the adjusted subtlist items, being * careful not to replace any of the jointree structure. - * (This'd be a lot cleaner if we could use query_tree_mutator.) + * (This'd be a lot cleaner if we could use + * query_tree_mutator.) */ subtlist = subquery->targetList; parse->targetList = (List *) @@ -375,15 +376,16 @@ pull_up_subqueries(Query *parse, Node *jtnode, bool below_outer_join) } /* - * Now append the adjusted rtable entries to upper query. - * (We hold off until after fixing the upper rtable entries; - * no point in running that code on the subquery ones too.) + * Now append the adjusted rtable entries to upper query. (We + * hold off until after fixing the upper rtable entries; no + * point in running that code on the subquery ones too.) */ parse->rtable = nconc(parse->rtable, subquery->rtable); /* * Pull up any FOR UPDATE markers, too. (OffsetVarNodes - * already adjusted the marker values, so just nconc the list.) + * already adjusted the marker values, so just nconc the + * list.) */ parse->rowMarks = nconc(parse->rowMarks, subquery->rowMarks); @@ -500,9 +502,9 @@ is_simple_subquery(Query *subquery) /* * Don't pull up a subquery that has any set-returning functions in - * its targetlist. Otherwise we might well wind up inserting - * set-returning functions into places where they mustn't go, - * such as quals of higher queries. + * its targetlist. Otherwise we might well wind up inserting + * set-returning functions into places where they mustn't go, such as + * quals of higher queries. */ if (expression_returns_set((Node *) subquery->targetList)) return false; @@ -724,8 +726,8 @@ preprocess_expression(Query *parse, Node *expr, int kind) /* * If the query has any join RTEs, try to replace join alias variables - * with base-relation variables, to allow quals to be pushed down. - * We must do this after sublink processing, since it does not recurse + * with base-relation variables, to allow quals to be pushed down. We + * must do this after sublink processing, since it does not recurse * into sublinks. * * The flattening pass is expensive enough that it seems worthwhile to |