diff options
Diffstat (limited to 'src/backend/optimizer/plan/planmain.c')
| -rw-r--r-- | src/backend/optimizer/plan/planmain.c | 85 |
1 files changed, 26 insertions, 59 deletions
diff --git a/src/backend/optimizer/plan/planmain.c b/src/backend/optimizer/plan/planmain.c index 1fcbe64e88..29cfccfef7 100644 --- a/src/backend/optimizer/plan/planmain.c +++ b/src/backend/optimizer/plan/planmain.c @@ -14,7 +14,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planmain.c,v 1.59 2000/09/12 21:06:54 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planmain.c,v 1.60 2000/09/29 18:21:33 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -32,8 +32,8 @@ #include "utils/memutils.h" -static Plan *subplanner(Query *root, List *flat_tlist, List *qual, - double tuple_fraction); +static Plan *subplanner(Query *root, List *flat_tlist, + double tuple_fraction); /*-------------------- @@ -75,46 +75,36 @@ query_planner(Query *root, List *tlist, double tuple_fraction) { - List *normal_qual; - List *noncachable_qual; - List *constant_qual; + List *constant_quals; List *var_only_tlist; Plan *subplan; /* - * If the query contains no relation references at all, it must be - * something like "SELECT 2+2;". Build a trivial "Result" plan. + * If the query has an empty join tree, then it's something easy like + * "SELECT 2+2;" or "INSERT ... VALUES()". Fall through quickly. */ - if (root->rtable == NIL) + if (root->jointree->fromlist == NIL) { - /* If it's not a select, it should have had a target relation... */ - if (root->commandType != CMD_SELECT) - elog(ERROR, "Empty range table for non-SELECT query"); - root->query_pathkeys = NIL; /* signal unordered result */ /* Make childless Result node to evaluate given tlist. */ - return (Plan *) make_result(tlist, root->qual, (Plan *) NULL); + return (Plan *) make_result(tlist, root->jointree->quals, + (Plan *) NULL); } /* - * Pull out any non-variable qual clauses so these can be put in a + * Pull out any non-variable WHERE clauses so these can be put in a * toplevel "Result" node, where they will gate execution of the whole * plan (the Result will not invoke its descendant plan unless the * quals are true). Note that any *really* non-variable quals will * have been optimized away by eval_const_expressions(). What we're * mostly interested in here is quals that depend only on outer-level * vars, although if the qual reduces to "WHERE FALSE" this path will - * also be taken. We also need a special case for quals that contain - * noncachable functions but no vars, such as "WHERE random() < 0.5". - * These cannot be treated as normal restriction or join quals, but - * they're not constants either. Instead, attach them to the qpqual - * of the top plan, so that they get evaluated once per potential - * output tuple. + * also be taken. */ - normal_qual = pull_constant_clauses((List *) root->qual, - &noncachable_qual, - &constant_qual); + root->jointree->quals = (Node *) + pull_constant_clauses((List *) root->jointree->quals, + &constant_quals); /* * Create a target list that consists solely of (resdom var) target @@ -132,18 +122,12 @@ query_planner(Query *root, /* * Choose the best access path and build a plan for it. */ - subplan = subplanner(root, var_only_tlist, normal_qual, tuple_fraction); - - /* - * Handle the noncachable quals. - */ - if (noncachable_qual) - subplan->qual = nconc(subplan->qual, noncachable_qual); + subplan = subplanner(root, var_only_tlist, tuple_fraction); /* * Build a result node to control the plan if we have constant quals. */ - if (constant_qual) + if (constant_quals) { /* @@ -151,7 +135,7 @@ query_planner(Query *root, * originally requested tlist. */ subplan = (Plan *) make_result(tlist, - (Node *) constant_qual, + (Node *) constant_quals, subplan); } else @@ -175,7 +159,6 @@ query_planner(Query *root, * for processing a single level of attributes. * * flat_tlist is the flattened target list - * qual is the qualification to be satisfied (restrict and join quals only) * tuple_fraction is the fraction of tuples we expect will be retrieved * * See query_planner() comments about the interpretation of tuple_fraction. @@ -185,7 +168,6 @@ query_planner(Query *root, static Plan * subplanner(Query *root, List *flat_tlist, - List *qual, double tuple_fraction) { List *joined_rels; @@ -210,9 +192,8 @@ subplanner(Query *root, root->equi_key_list = NIL; build_base_rel_tlists(root, flat_tlist); - (void) add_join_quals_to_rels(root, (Node *) root->jointree); - /* this must happen after add_join_quals_to_rels: */ - add_restrict_and_join_to_rels(root, qual); + + (void) distribute_quals_to_rels(root, (Node *) root->jointree); /* * Make sure we have RelOptInfo nodes for all relations to be joined. @@ -270,26 +251,7 @@ subplanner(Query *root, final_rel = make_one_rel(root); if (!final_rel) - { - - /* - * We expect to end up here for a trivial INSERT ... VALUES query - * (which will have a target relation, so it gets past - * query_planner's check for empty range table; but the target rel - * is not in the join tree, so we find there is nothing to join). - * - * It's also possible to get here if the query was rewritten by the - * rule processor (creating dummy rangetable entries that are not in - * the join tree) but the rules either did nothing or were simplified - * to nothing by constant-expression folding. So, don't complain. - */ - root->query_pathkeys = NIL; /* signal unordered result */ - - /* Make childless Result node to evaluate given tlist. */ - resultplan = (Plan *) make_result(flat_tlist, (Node *) qual, - (Plan *) NULL); - goto plan_built; - } + elog(ERROR, "subplanner: failed to construct a relation"); #ifdef NOT_USED /* fix xfunc */ @@ -395,7 +357,10 @@ plan_built: /* * Must copy the completed plan tree and its pathkeys out of temporary - * context. + * context. We also have to copy the rtable in case it contains any + * subqueries. (If it does, they'll have been modified during the + * recursive invocation of planner.c, and hence will contain substructure + * allocated in my temporary context...) */ MemoryContextSwitchTo(oldcxt); @@ -403,6 +368,8 @@ plan_built: root->query_pathkeys = copyObject(root->query_pathkeys); + root->rtable = copyObject(root->rtable); + /* * Now we can release the Path storage. */ |