diff options
Diffstat (limited to 'src/backend/optimizer/plan/planmain.c')
| -rw-r--r-- | src/backend/optimizer/plan/planmain.c | 78 |
1 files changed, 13 insertions, 65 deletions
diff --git a/src/backend/optimizer/plan/planmain.c b/src/backend/optimizer/plan/planmain.c index cfa134a3889..acc4eb5d938 100644 --- a/src/backend/optimizer/plan/planmain.c +++ b/src/backend/optimizer/plan/planmain.c @@ -3,29 +3,31 @@ * planmain.c * Routines to plan a single query * + * What's in a name, anyway? The top-level entry point of the planner/ + * optimizer is over in planner.c, not here as you might think from the + * file name. But this is the main code for planning a basic join operation, + * shorn of features like subselects, inheritance, aggregates, grouping, + * and so on. (Those are the things planner.c deals with.) + * * Portions Copyright (c) 1996-2000, PostgreSQL, Inc * Portions Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planmain.c,v 1.52 2000/02/15 20:49:18 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planmain.c,v 1.53 2000/03/21 05:11:58 tgl Exp $ * *------------------------------------------------------------------------- */ -#include <sys/types.h> - #include "postgres.h" +#include <sys/types.h> #include "optimizer/clauses.h" #include "optimizer/cost.h" #include "optimizer/pathnode.h" #include "optimizer/paths.h" #include "optimizer/planmain.h" -#include "optimizer/prep.h" -#include "optimizer/subselect.h" #include "optimizer/tlist.h" -#include "utils/lsyscache.h" static Plan *subplanner(Query *root, List *flat_tlist, List *qual, @@ -34,19 +36,15 @@ static Plan *subplanner(Query *root, List *flat_tlist, List *qual, /*-------------------- * query_planner - * Routine to create a query plan. It does so by first creating a - * subplan for the topmost level of attributes in the query. Then, - * it modifies all target list and qualifications to consider the next - * level of nesting and creates a plan for this modified query by - * recursively calling itself. The two pieces are then merged together - * by creating a result node that indicates which attributes should - * be placed where and any relation level qualifications to be - * satisfied. + * Generate a plan for a basic query, which may involve joins but + * not any fancier features. * - * tlist is the target list of the query (do NOT use root->targetList!) + * tlist is the target list the query should produce (NOT root->targetList!) * qual is the qualification of the query (likewise!) * tuple_fraction is the fraction of tuples we expect will be retrieved * + * qual must already have been converted to implicit-AND form. + * * Note: the Query node now also includes a query_pathkeys field, which * is both an input and an output of query_planner(). The input value * signals query_planner that the indicated sort order is wanted in the @@ -84,46 +82,6 @@ query_planner(Query *root, Plan *subplan; /* - * Note: union_planner should already have done constant folding - * in both the tlist and qual, so we don't do it again here - * (indeed, we may be getting a flattened var-only tlist anyway). - * - * Is there any value in re-folding the qual after canonicalize_qual? - */ - - /* - * Canonicalize the qual, and convert it to implicit-AND format. - */ - qual = canonicalize_qual((Expr *) qual, true); -#ifdef OPTIMIZER_DEBUG - printf("After canonicalize_qual()\n"); - pprint(qual); -#endif - - /* Replace uplevel vars with Param nodes */ - if (PlannerQueryLevel > 1) - { - tlist = (List *) SS_replace_correlation_vars((Node *) tlist); - qual = (List *) SS_replace_correlation_vars((Node *) qual); - } - - /* Expand SubLinks to SubPlans */ - if (root->hasSubLinks) - { - tlist = (List *) SS_process_sublinks((Node *) tlist); - qual = (List *) SS_process_sublinks((Node *) qual); - if (root->groupClause != NIL) - { - /* - * Check for ungrouped variables passed to subplans. - * Note we do NOT do this for subplans in WHERE; it's legal - * there because WHERE is evaluated pre-GROUP. - */ - check_subplans_for_ungrouped_vars((Node *) tlist, root, tlist); - } - } - - /* * If the query contains no relation references at all, it must be * something like "SELECT 2+2;". Build a trivial "Result" plan. */ @@ -192,16 +150,6 @@ query_planner(Query *root, } return subplan; - -#ifdef NOT_USED - - /* - * Destructively modify the query plan's targetlist to add fjoin lists - * to flatten functions that return sets of base types - */ - subplan->targetlist = generate_fjoin(subplan->targetlist); -#endif - } /* |