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/*-------------------------------------------------------------------------
*
* planner.c--
* The query optimizer external interface.
*
* Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.33 1998/09/03 02:34:30 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#include <sys/types.h>
#include <string.h>
#include "postgres.h"
#include "nodes/pg_list.h"
#include "nodes/plannodes.h"
#include "nodes/parsenodes.h"
#include "nodes/relation.h"
#include "parser/parse_expr.h"
#include "utils/elog.h"
#include "utils/lsyscache.h"
#include "access/heapam.h"
#include "optimizer/internal.h"
#include "optimizer/planner.h"
#include "optimizer/plancat.h"
#include "optimizer/prep.h"
#include "optimizer/planmain.h"
#include "optimizer/subselect.h"
#include "optimizer/paths.h"
#include "optimizer/cost.h"
/* DATA STRUCTURE CREATION/MANIPULATION ROUTINES */
#include "nodes/relation.h"
#include "optimizer/clauseinfo.h"
#include "optimizer/joininfo.h"
#include "optimizer/keys.h"
#include "optimizer/ordering.h"
#include "optimizer/pathnode.h"
#include "optimizer/clauses.h"
#include "optimizer/tlist.h"
#include "optimizer/var.h"
#include "executor/executor.h"
static Plan *make_sortplan(List *tlist, List *sortcls, Plan *plannode);
extern Plan *make_groupPlan(List **tlist, bool tuplePerGroup,
List *groupClause, Plan *subplan);
/*****************************************************************************
*
* Query optimizer entry point
*
*****************************************************************************/
Plan *
planner(Query *parse)
{
Plan *result_plan;
PlannerQueryLevel = 1;
PlannerVarParam = NULL;
PlannerParamVar = NULL;
PlannerInitPlan = NULL;
PlannerPlanId = 0;
transformKeySetQuery(parse);
result_plan = union_planner(parse);
Assert(PlannerQueryLevel == 1);
if (PlannerPlanId > 0)
{
result_plan->initPlan = PlannerInitPlan;
(void) SS_finalize_plan(result_plan);
}
result_plan->nParamExec = length(PlannerParamVar);
return result_plan;
}
/*
* union_planner--
*
* Invokes the planner on union queries if there are any left,
* recursing if necessary to get them all, then processes normal plans.
*
* Returns a query plan.
*
*/
Plan *
union_planner(Query *parse)
{
List *tlist = parse->targetList;
/*
* copy the original tlist, we will need the original one for the AGG
* node later on
*/
List *new_tlist = new_unsorted_tlist(tlist);
List *rangetable = parse->rtable;
Plan *result_plan = (Plan *) NULL;
Index rt_index;
if (parse->unionClause)
{
result_plan = (Plan *) plan_union_queries(parse);
/* XXX do we need to do this? bjm 12/19/97 */
tlist = preprocess_targetlist(tlist,
parse->commandType,
parse->resultRelation,
parse->rtable);
}
else if ((rt_index =
first_inherit_rt_entry(rangetable)) != -1)
{
result_plan = (Plan *) plan_inherit_queries(parse, rt_index);
/* XXX do we need to do this? bjm 12/19/97 */
tlist = preprocess_targetlist(tlist,
parse->commandType,
parse->resultRelation,
parse->rtable);
}
else
{
List **vpm = NULL;
/*
* This is only necessary if aggregates are in use in queries
* like: SELECT sid FROM part GROUP BY sid HAVING MIN(pid) > 1;
* (pid is used but never selected for!!!) because the function
* 'query_planner' creates the plan for the lefttree of the
* 'GROUP' node and returns only those attributes contained in
* 'tlist'. The original 'tlist' contains only 'sid' here and
* that's why we have to to extend it to attributes which are not
* selected but are used in the havingQual.
*/
/*
* 'check_having_qual_for_vars' takes the havingQual and the
* actual 'tlist' as arguments and recursively scans the
* havingQual for attributes (VAR nodes) that are not contained in
* 'tlist' yet. If so, it creates a new entry and attaches it to
* the list 'new_tlist' (consisting of the VAR node and the RESDOM
* node as usual with tlists :-) )
*/
if (parse->hasAggs)
{
if (parse->havingQual != NULL)
new_tlist = check_having_qual_for_vars(parse->havingQual, new_tlist);
}
new_tlist = preprocess_targetlist(new_tlist,
parse->commandType,
parse->resultRelation,
parse->rtable);
/* Here starts the original (pre having) code */
tlist = preprocess_targetlist(tlist,
parse->commandType,
parse->resultRelation,
parse->rtable);
if (parse->rtable != NULL)
{
vpm = (List **) palloc(length(parse->rtable) * sizeof(List *));
memset(vpm, 0, length(parse->rtable) * sizeof(List *));
}
PlannerVarParam = lcons(vpm, PlannerVarParam);
result_plan = query_planner(parse,
parse->commandType,
new_tlist,
(List *) parse->qual);
PlannerVarParam = lnext(PlannerVarParam);
if (vpm != NULL)
pfree(vpm);
}
/*
* If we have a GROUP BY clause, insert a group node (with the
* appropriate sort node.)
*/
if (parse->groupClause)
{
bool tuplePerGroup;
/*
* decide whether how many tuples per group the Group node needs
* to return. (Needs only one tuple per group if no aggregate is
* present. Otherwise, need every tuple from the group to do the
* aggregation.)
*/
tuplePerGroup = parse->hasAggs;
/* Use 'new_tlist' instead of 'tlist' */
result_plan =
make_groupPlan(&new_tlist,
tuplePerGroup,
parse->groupClause,
result_plan);
}
/*
* If aggregate is present, insert the agg node
*/
if (parse->hasAggs)
{
int old_length = 0,
new_length = 0;
/*
* Create the AGG node but use 'tlist' not 'new_tlist' as target
* list because we don't want the additional attributes (only used
* for the havingQual, see above) to show up in the result
*/
result_plan = (Plan *) make_agg(tlist, result_plan);
/*
* set the varno/attno entries to the appropriate references to
* the result tuple of the subplans.
*/
((Agg *) result_plan)->aggs =
set_agg_tlist_references((Agg *) result_plan);
if (parse->havingQual != NULL)
{
List *clause;
List **vpm = NULL;
/*
* stuff copied from above to handle the use of attributes
* from outside in subselects
*/
if (parse->rtable != NULL)
{
vpm = (List **) palloc(length(parse->rtable) * sizeof(List *));
memset(vpm, 0, length(parse->rtable) * sizeof(List *));
}
PlannerVarParam = lcons(vpm, PlannerVarParam);
/*
* There is a subselect in the havingQual, so we have to
* process it using the same function as for a subselect in
* 'where'
*/
if (parse->hasSubLinks)
parse->havingQual = SS_process_sublinks((Node *) parse->havingQual);
/* convert the havingQual to conjunctive normal form (cnf) */
parse->havingQual = (Node *) cnfify((Expr *) (Node *) parse->havingQual, true);
/*
* Calculate the opfids from the opnos (=select the correct
* functions for the used VAR datatypes)
*/
parse->havingQual = (Node *) fix_opids((List *) parse->havingQual);
((Agg *) result_plan)->plan.qual = (List *) parse->havingQual;
/*
* Check every clause of the havingQual for aggregates used
* and append them to result_plan->aggs
*/
foreach(clause, ((Agg *) result_plan)->plan.qual)
{
/*
* Make sure there are aggregates in the havingQual if so,
* the list must be longer after
* check_having_qual_for_aggs
*/
old_length = length(((Agg *) result_plan)->aggs);
((Agg *) result_plan)->aggs = nconc(((Agg *) result_plan)->aggs,
check_having_qual_for_aggs((Node *) lfirst(clause),
((Agg *) result_plan)->plan.lefttree->targetlist,
((List *) parse->groupClause)));
/*
* Have a look at the length of the returned list. If
* there is no difference, no aggregates have been found
* and that means, that the Qual belongs to the where
* clause
*/
if (((new_length = length(((Agg *) result_plan)->aggs)) == old_length) ||
(new_length == 0))
{
elog(ERROR, "This could have been done in a where clause!!");
return (Plan *) NIL;
}
}
PlannerVarParam = lnext(PlannerVarParam);
if (vpm != NULL)
pfree(vpm);
}
}
/*
* For now, before we hand back the plan, check to see if there is a
* user-specified sort that needs to be done. Eventually, this will
* be moved into the guts of the planner s.t. user specified sorts
* will be considered as part of the planning process. Since we can
* only make use of user-specified sorts in special cases, we can do
* the optimization step later.
*/
if (parse->uniqueFlag)
{
Plan *sortplan = make_sortplan(tlist, parse->sortClause, result_plan);
return (Plan *) make_unique(tlist, sortplan, parse->uniqueFlag);
}
else
{
if (parse->sortClause)
return make_sortplan(tlist, parse->sortClause, result_plan);
else
return (Plan *) result_plan;
}
}
/*
* make_sortplan--
* Returns a sortplan which is basically a SORT node attached to the
* top of the plan returned from the planner. It also adds the
* cost of sorting into the plan.
*
* sortkeys: ( resdom1 resdom2 resdom3 ...)
* sortops: (sortop1 sortop2 sortop3 ...)
*/
static Plan *
make_sortplan(List *tlist, List *sortcls, Plan *plannode)
{
Plan *sortplan = (Plan *) NULL;
List *temp_tlist = NIL;
List *i = NIL;
Resdom *resnode = (Resdom *) NULL;
Resdom *resdom = (Resdom *) NULL;
int keyno = 1;
/*
* First make a copy of the tlist so that we don't corrupt the the
* original .
*/
temp_tlist = new_unsorted_tlist(tlist);
foreach(i, sortcls)
{
SortClause *sortcl = (SortClause *) lfirst(i);
resnode = sortcl->resdom;
resdom = tlist_resdom(temp_tlist, resnode);
/*
* Order the resdom keys and replace the operator OID for each key
* with the regproc OID.
*/
resdom->reskey = keyno;
resdom->reskeyop = get_opcode(sortcl->opoid);
keyno += 1;
}
sortplan = (Plan *) make_sort(temp_tlist,
_TEMP_RELATION_ID_,
(Plan *) plannode,
length(sortcls));
/*
* XXX Assuming that an internal sort has no. cost. This is wrong, but
* given that at this point, we don't know the no. of tuples returned,
* etc, we can't do better than to add a constant cost. This will be
* fixed once we move the sort further into the planner, but for now
* ... functionality....
*/
sortplan->cost = plannode->cost;
return sortplan;
}
/*
* pg_checkretval() -- check return value of a list of sql parse
* trees.
*
* The return value of a sql function is the value returned by
* the final query in the function. We do some ad-hoc define-time
* type checking here to be sure that the user is returning the
* type he claims.
*/
void
pg_checkretval(Oid rettype, QueryTreeList *queryTreeList)
{
Query *parse;
List *tlist;
List *rt;
int cmd;
Type typ;
Resdom *resnode;
Relation reln;
Oid relid;
Oid tletype;
int relnatts;
int i;
/* find the final query */
parse = queryTreeList->qtrees[queryTreeList->len - 1];
/*
* test 1: if the last query is a utility invocation, then there had
* better not be a return value declared.
*/
if (parse->commandType == CMD_UTILITY)
{
if (rettype == InvalidOid)
return;
else
elog(ERROR, "return type mismatch in function decl: final query is a catalog utility");
}
/* okay, it's an ordinary query */
tlist = parse->targetList;
rt = parse->rtable;
cmd = parse->commandType;
/*
* test 2: if the function is declared to return no value, then the
* final query had better not be a retrieve.
*/
if (rettype == InvalidOid)
{
if (cmd == CMD_SELECT)
elog(ERROR,
"function declared with no return type, but final query is a retrieve");
else
return;
}
/* by here, the function is declared to return some type */
if ((typ = typeidType(rettype)) == NULL)
elog(ERROR, "can't find return type %d for function\n", rettype);
/*
* test 3: if the function is declared to return a value, then the
* final query had better be a retrieve.
*/
if (cmd != CMD_SELECT)
elog(ERROR, "function declared to return type %s, but final query is not a retrieve", typeTypeName(typ));
/*
* test 4: for base type returns, the target list should have exactly
* one entry, and its type should agree with what the user declared.
*/
if (typeTypeRelid(typ) == InvalidOid)
{
if (ExecTargetListLength(tlist) > 1)
elog(ERROR, "function declared to return %s returns multiple values in final retrieve", typeTypeName(typ));
resnode = (Resdom *) ((TargetEntry *) lfirst(tlist))->resdom;
if (resnode->restype != rettype)
elog(ERROR, "return type mismatch in function: declared to return %s, returns %s", typeTypeName(typ), typeidTypeName(resnode->restype));
/* by here, base return types match */
return;
}
/*
* If the target list is of length 1, and the type of the varnode in
* the target list is the same as the declared return type, this is
* okay. This can happen, for example, where the body of the function
* is 'retrieve (x = func2())', where func2 has the same return type
* as the function that's calling it.
*/
if (ExecTargetListLength(tlist) == 1)
{
resnode = (Resdom *) ((TargetEntry *) lfirst(tlist))->resdom;
if (resnode->restype == rettype)
return;
}
/*
* By here, the procedure returns a (set of) tuples. This part of the
* typechecking is a hack. We look up the relation that is the
* declared return type, and be sure that attributes 1 .. n in the
* target list match the declared types.
*/
reln = heap_open(typeTypeRelid(typ));
if (!RelationIsValid(reln))
elog(ERROR, "cannot open relation relid %d", typeTypeRelid(typ));
relid = reln->rd_id;
relnatts = reln->rd_rel->relnatts;
if (ExecTargetListLength(tlist) != relnatts)
elog(ERROR, "function declared to return type %s does not retrieve (%s.*)", typeTypeName(typ), typeTypeName(typ));
/* expect attributes 1 .. n in order */
for (i = 1; i <= relnatts; i++)
{
TargetEntry *tle = lfirst(tlist);
Node *thenode = tle->expr;
tlist = lnext(tlist);
tletype = exprType(thenode);
#if 0 /* fix me */
/* this is tedious */
if (IsA(thenode, Var))
tletype = (Oid) ((Var *) thenode)->vartype;
else if (IsA(thenode, Const))
tletype = (Oid) ((Const *) thenode)->consttype;
else if (IsA(thenode, Param))
tletype = (Oid) ((Param *) thenode)->paramtype;
else if (IsA(thenode, Expr))
tletype = Expr;
else if (IsA(thenode, LispList))
{
thenode = lfirst(thenode);
if (IsA(thenode, Oper))
tletype = (Oid) get_opresulttype((Oper *) thenode);
else if (IsA(thenode, Func))
tletype = (Oid) get_functype((Func *) thenode);
else
elog(ERROR, "function declared to return type %s does not retrieve (%s.all)", typeTypeName(typ), typeTypeName(typ));
}
else
elog(ERROR, "function declared to return type %s does not retrieve (%s.all)", typeTypeName(typ), typeTypeName(typ));
#endif
/* reach right in there, why don't you? */
if (tletype != reln->rd_att->attrs[i - 1]->atttypid)
elog(ERROR, "function declared to return type %s does not retrieve (%s.all)", typeTypeName(typ), typeTypeName(typ));
}
heap_close(reln);
/* success */
return;
}