/*------------------------------------------------------------------------- * * initsplan.c-- * Target list, qualification, joininfo initialization routines * * Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION * $Header: /usr/local/cvsroot/pgsql/src/backend/optimizer/plan/initsplan.c,v 1.8 1997/09/08 21:45:19 momjian Exp $ * *------------------------------------------------------------------------- */ #include #include "postgres.h" #include "nodes/pg_list.h" #include "nodes/plannodes.h" #include "nodes/parsenodes.h" #include "nodes/relation.h" #include "nodes/makefuncs.h" #include "utils/lsyscache.h" #include "utils/palloc.h" #include "optimizer/internal.h" #include "optimizer/planmain.h" #include "optimizer/joininfo.h" #include "optimizer/pathnode.h" #include "optimizer/tlist.h" #include "optimizer/var.h" #include "optimizer/clauses.h" #include "optimizer/cost.h" extern int Quiet; static void add_clause_to_rels(Query *root, List *clause); static void add_join_clause_info_to_rels(Query *root, CInfo *clauseinfo, List *join_relids); static void add_vars_to_rels(Query *root, List *vars, List *join_relids); static MergeOrder *mergesortop(Expr *clause); static Oid hashjoinop(Expr *clause); /***************************************************************************** * * TARGET LISTS * *****************************************************************************/ /* * initialize_rel_nodes-- * Creates rel nodes for every relation mentioned in the target list * 'tlist' (if a node hasn't already been created) and adds them to * *query-relation-list*. Creates targetlist entries for each member of * 'tlist' and adds them to the tlist field of the appropriate rel node. * * Returns nothing. */ void initialize_base_rels_list(Query *root, List *tlist) { List *tlist_vars = NIL; List *l = NIL; List *tvar = NIL; foreach(l, tlist) { TargetEntry *entry = (TargetEntry *) lfirst(l); tlist_vars = append(tlist_vars, pull_var_clause(entry->expr)); } /* now, the target list only contains Var nodes */ foreach(tvar, tlist_vars) { Var *var; Index varno; Rel *result; var = (Var *) lfirst(tvar); varno = var->varno; result = get_base_rel(root, varno); add_tl_element(result, var); } } /* * add_missing_variables_to_base_rels - * If we have range variable(s) in the FROM clause that does not appear * in the target list nor qualifications, we add it to the base relation * list. For instance, "select f.x from foo f, foo f2" is a join of f and * f2. Note that if we have "select foo.x from foo f", it also gets turned * into a join. */ void add_missing_vars_to_base_rels(Query *root, List *tlist) { List *l; int varno; varno = 1; foreach(l, root->rtable) { RangeTblEntry *rte = (RangeTblEntry *) lfirst(l); List *relids; Rel *result; Var *var; relids = lconsi(varno, NIL); if (rte->inFromCl && !rel_member(relids, root->base_relation_list_)) { var = makeVar(varno, -2, 26, varno, -2); /* add it to base_relation_list_ */ result = get_base_rel(root, varno); add_tl_element(result, var); } pfree(relids); varno++; } return; } /***************************************************************************** * * QUALIFICATIONS * *****************************************************************************/ /* * initialize-qualification-- * Initializes ClauseInfo and JoinInfo fields of relation entries for all * relations appearing within clauses. Creates new relation entries if * necessary, adding them to *query-relation-list*. * * Returns nothing of interest. */ void initialize_base_rels_jinfo(Query *root, List *clauses) { List *clause; foreach(clause, clauses) { add_clause_to_rels(root, lfirst(clause)); } return; } /* * add-clause-to-rels-- * Add clause information to either the 'ClauseInfo' or 'JoinInfo' field * of a relation entry(depending on whether or not the clause is a join) * by creating a new ClauseInfo node and setting appropriate fields * within the nodes. * * Returns nothing of interest. */ static void add_clause_to_rels(Query *root, List *clause) { List *relids; List *vars; CInfo *clauseinfo = makeNode(CInfo); /* * Retrieve all relids and vars contained within the clause. */ clause_relids_vars((Node *) clause, &relids, &vars); clauseinfo->clause = (Expr *) clause; clauseinfo->notclause = contains_not((Node *) clause); clauseinfo->selectivity = 0; clauseinfo->indexids = NIL; clauseinfo->mergesortorder = (MergeOrder *) NULL; clauseinfo->hashjoinoperator = (Oid) 0; if (length(relids) == 1) { Rel *rel = get_base_rel(root, lfirsti(relids)); /* * There is only one relation participating in 'clause', so * 'clause' must be a restriction clause. */ /* * the selectivity of the clause must be computed regardless of * whether it's a restriction or a join clause */ if (is_funcclause((Node *) clause)) { /* * XXX If we have a func clause set selectivity to 1/3, really * need a true selectivity function. */ clauseinfo->selectivity = (Cost) 0.3333333; } else { clauseinfo->selectivity = compute_clause_selec(root, (Node *) clause, NIL); } rel->clauseinfo = lcons(clauseinfo, rel->clauseinfo); } else { /* * 'clause' is a join clause, since there is more than one atom in * the relid list. */ if (is_funcclause((Node *) clause)) { /* * XXX If we have a func clause set selectivity to 1/3, really * need a true selectivity function. */ clauseinfo->selectivity = (Cost) 0.3333333; } else { clauseinfo->selectivity = compute_clause_selec(root, (Node *) clause, NIL); } add_join_clause_info_to_rels(root, clauseinfo, relids); add_vars_to_rels(root, vars, relids); } } /* * add-join-clause-info-to-rels-- * For every relation participating in a join clause, add 'clauseinfo' to * the appropriate joininfo node(creating a new one and adding it to the * appropriate rel node if necessary). * * 'clauseinfo' describes the join clause * 'join-relids' is the list of relations participating in the join clause * * Returns nothing. * */ static void add_join_clause_info_to_rels(Query *root, CInfo *clauseinfo, List *join_relids) { List *join_relid; foreach(join_relid, join_relids) { JInfo *joininfo; List *other_rels = NIL; List *rel; foreach(rel, join_relids) { if (lfirsti(rel) != lfirsti(join_relid)) other_rels = lappendi(other_rels, lfirsti(rel)); } joininfo = find_joininfo_node(get_base_rel(root, lfirsti(join_relid)), other_rels); joininfo->jinfoclauseinfo = lcons(copyObject((void *) clauseinfo), joininfo->jinfoclauseinfo); } } /* * add-vars-to-rels-- * For each variable appearing in a clause, * (1) If a targetlist entry for the variable is not already present in * the appropriate relation's target list, add one. * (2) If a targetlist entry is already present, but the var is part of a * join clause, add the relids of the join relations to the JoinList * entry of the targetlist entry. * * 'vars' is the list of var nodes * 'join-relids' is the list of relids appearing in the join clause * (if this is a join clause) * * Returns nothing. */ static void add_vars_to_rels(Query *root, List *vars, List *join_relids) { Var *var; List *temp = NIL; Rel *rel = (Rel *) NULL; TargetEntry *tlistentry; foreach(temp, vars) { var = (Var *) lfirst(temp); rel = get_base_rel(root, var->varno); tlistentry = tlistentry_member(var, rel->targetlist); if (tlistentry == NULL) /* add a new entry */ add_tl_element(rel, var); } } /***************************************************************************** * * JOININFO * *****************************************************************************/ /* * initialize-join-clause-info-- * Set the MergeSortable or HashJoinable field for every joininfo node * (within a rel node) and the MergeSortOrder or HashJoinOp field for * each clauseinfo node(within a joininfo node) for all relations in a * query. * * Returns nothing. */ void initialize_join_clause_info(List *rel_list) { List *x, *y, *z; Rel *rel; JInfo *joininfo; CInfo *clauseinfo; Expr *clause; foreach(x, rel_list) { rel = (Rel *) lfirst(x); foreach(y, rel->joininfo) { joininfo = (JInfo *) lfirst(y); foreach(z, joininfo->jinfoclauseinfo) { clauseinfo = (CInfo *) lfirst(z); clause = clauseinfo->clause; if (join_clause_p((Node *) clause)) { MergeOrder *sortop = (MergeOrder *) NULL; Oid hashop = (Oid) NULL; if (_enable_mergesort_) sortop = mergesortop(clause); if (_enable_hashjoin_) hashop = hashjoinop(clause); if (sortop) { clauseinfo->mergesortorder = sortop; joininfo->mergesortable = true; } if (hashop) { clauseinfo->hashjoinoperator = hashop; joininfo->hashjoinable = true; } } } } } } /* * mergesortop-- * Returns the mergesort operator of an operator iff 'clause' is * mergesortable, i.e., both operands are single vars and the operator is * a mergesortable operator. */ static MergeOrder * mergesortop(Expr *clause) { Oid leftOp, rightOp; bool sortable; sortable = op_mergesortable(((Oper *) clause->oper)->opno, (get_leftop(clause))->vartype, (get_rightop(clause))->vartype, &leftOp, &rightOp); if (sortable) { MergeOrder *morder = makeNode(MergeOrder); morder->join_operator = ((Oper *) clause->oper)->opno; morder->left_operator = leftOp; morder->right_operator = rightOp; morder->left_type = (get_leftop(clause))->vartype; morder->right_type = (get_rightop(clause))->vartype; return (morder); } else return (NULL); } /* * hashjoinop-- * Returns the hashjoin operator of an operator iff 'clause' is * hashjoinable, i.e., both operands are single vars and the operator is * a hashjoinable operator. */ static Oid hashjoinop(Expr *clause) { return (op_hashjoinable(((Oper *) clause->oper)->opno, (get_leftop(clause))->vartype, (get_rightop(clause))->vartype)); }