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|
/*-------------------------------------------------------------------------
*
* rewriteHandler.c
*
* Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteHandler.c,v 1.44 1999/05/25 13:16:10 wieck Exp $
*
*-------------------------------------------------------------------------
*/
#include <string.h>
#include "postgres.h"
#include "miscadmin.h"
#include "utils/palloc.h"
#include "utils/elog.h"
#include "utils/rel.h"
#include "nodes/pg_list.h"
#include "nodes/primnodes.h"
#include "nodes/relation.h"
#include "parser/parsetree.h" /* for parsetree manipulation */
#include "parser/parse_relation.h"
#include "nodes/parsenodes.h"
/***S*I***/
#include "parser/parse_node.h"
#include "parser/parse_target.h"
#include "parser/analyze.h"
#include "optimizer/prep.h"
#include "rewrite/rewriteSupport.h"
#include "rewrite/rewriteHandler.h"
#include "rewrite/rewriteManip.h"
#include "rewrite/locks.h"
#include "commands/creatinh.h"
#include "access/heapam.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
#include "utils/acl.h"
#include "catalog/pg_shadow.h"
#include "catalog/pg_type.h"
static RewriteInfo *gatherRewriteMeta(Query *parsetree,
Query *rule_action,
Node *rule_qual,
int rt_index,
CmdType event,
bool *instead_flag);
static bool rangeTableEntry_used(Node *node, int rt_index, int sublevels_up);
static bool attribute_used(Node *node, int rt_index, int attno, int sublevels_up);
static void modifyAggrefUplevel(Node *node);
static void modifyAggrefChangeVarnodes(Node **nodePtr, int rt_index, int new_index, int sublevels_up);
static void modifyAggrefDropQual(Node **nodePtr, Node *orignode, Expr *expr);
static SubLink *modifyAggrefMakeSublink(Expr *origexp, Query *parsetree);
static void modifyAggrefQual(Node **nodePtr, Query *parsetree);
static bool checkQueryHasAggs(Node *node);
static Query *fireRIRrules(Query *parsetree);
/*
* gatherRewriteMeta -
* Gather meta information about parsetree, and rule. Fix rule body
* and qualifier so that they can be mixed with the parsetree and
* maintain semantic validity
*/
static RewriteInfo *
gatherRewriteMeta(Query *parsetree,
Query *rule_action,
Node *rule_qual,
int rt_index,
CmdType event,
bool *instead_flag)
{
RewriteInfo *info;
int rt_length;
int result_reln;
info = (RewriteInfo *) palloc(sizeof(RewriteInfo));
info->rt_index = rt_index;
info->event = event;
info->instead_flag = *instead_flag;
info->rule_action = (Query *) copyObject(rule_action);
info->rule_qual = (Node *) copyObject(rule_qual);
if (info->rule_action == NULL)
info->nothing = TRUE;
else
{
info->nothing = FALSE;
info->action = info->rule_action->commandType;
info->current_varno = rt_index;
info->rt = parsetree->rtable;
rt_length = length(info->rt);
info->rt = nconc(info->rt, copyObject(info->rule_action->rtable));
info->new_varno = PRS2_NEW_VARNO + rt_length;
OffsetVarNodes(info->rule_action->qual, rt_length, 0);
OffsetVarNodes((Node *) info->rule_action->targetList, rt_length, 0);
OffsetVarNodes(info->rule_qual, rt_length, 0);
ChangeVarNodes((Node *) info->rule_action->qual,
PRS2_CURRENT_VARNO + rt_length, rt_index, 0);
ChangeVarNodes((Node *) info->rule_action->targetList,
PRS2_CURRENT_VARNO + rt_length, rt_index, 0);
ChangeVarNodes(info->rule_qual,
PRS2_CURRENT_VARNO + rt_length, rt_index, 0);
/*
* bug here about replace CURRENT -- sort of replace current is
* deprecated now so this code shouldn't really need to be so
* clutzy but.....
*/
if (info->action != CMD_SELECT)
{ /* i.e update XXXXX */
int new_result_reln = 0;
result_reln = info->rule_action->resultRelation;
switch (result_reln)
{
case PRS2_CURRENT_VARNO:
new_result_reln = rt_index;
break;
case PRS2_NEW_VARNO: /* XXX */
default:
new_result_reln = result_reln + rt_length;
break;
}
info->rule_action->resultRelation = new_result_reln;
}
}
return info;
}
/*
* rangeTableEntry_used -
* we need to process a RTE for RIR rules only if it is
* referenced somewhere in var nodes of the query.
*/
static bool
rangeTableEntry_used(Node *node, int rt_index, int sublevels_up)
{
if (node == NULL)
return FALSE;
switch(nodeTag(node)) {
case T_TargetEntry:
{
TargetEntry *tle = (TargetEntry *)node;
return rangeTableEntry_used(
(Node *)(tle->expr),
rt_index,
sublevels_up);
}
break;
case T_Aggref:
{
Aggref *aggref = (Aggref *)node;
return rangeTableEntry_used(
(Node *)(aggref->target),
rt_index,
sublevels_up);
}
break;
case T_GroupClause:
return FALSE;
case T_Expr:
{
Expr *exp = (Expr *)node;
return rangeTableEntry_used(
(Node *)(exp->args),
rt_index,
sublevels_up);
}
break;
case T_Iter:
{
Iter *iter = (Iter *)node;
return rangeTableEntry_used(
(Node *)(iter->iterexpr),
rt_index,
sublevels_up);
}
break;
case T_ArrayRef:
{
ArrayRef *ref = (ArrayRef *)node;
if (rangeTableEntry_used(
(Node *)(ref->refupperindexpr),
rt_index,
sublevels_up))
return TRUE;
if (rangeTableEntry_used(
(Node *)(ref->reflowerindexpr),
rt_index,
sublevels_up))
return TRUE;
if (rangeTableEntry_used(
(Node *)(ref->refexpr),
rt_index,
sublevels_up))
return TRUE;
if (rangeTableEntry_used(
(Node *)(ref->refassgnexpr),
rt_index,
sublevels_up))
return TRUE;
return FALSE;
}
break;
case T_Var:
{
Var *var = (Var *)node;
if (var->varlevelsup == sublevels_up)
return var->varno == rt_index;
else
return FALSE;
}
break;
case T_Param:
return FALSE;
case T_Const:
return FALSE;
case T_List:
{
List *l;
foreach (l, (List *)node) {
if (rangeTableEntry_used(
(Node *)lfirst(l),
rt_index,
sublevels_up))
return TRUE;
}
return FALSE;
}
break;
case T_SubLink:
{
SubLink *sub = (SubLink *)node;
if (rangeTableEntry_used(
(Node *)(sub->lefthand),
rt_index,
sublevels_up))
return TRUE;
if (rangeTableEntry_used(
(Node *)(sub->subselect),
rt_index,
sublevels_up + 1))
return TRUE;
return FALSE;
}
break;
case T_CaseExpr:
{
CaseExpr *exp = (CaseExpr *)node;
if (rangeTableEntry_used(
(Node *)(exp->args),
rt_index,
sublevels_up))
return TRUE;
if (rangeTableEntry_used(
(Node *)(exp->defresult),
rt_index,
sublevels_up))
return TRUE;
return FALSE;
}
break;
case T_CaseWhen:
{
CaseWhen *when = (CaseWhen *)node;
if (rangeTableEntry_used(
(Node *)(when->expr),
rt_index,
sublevels_up))
return TRUE;
if (rangeTableEntry_used(
(Node *)(when->result),
rt_index,
sublevels_up))
return TRUE;
return FALSE;
}
break;
case T_Query:
{
Query *qry = (Query *)node;
if (rangeTableEntry_used(
(Node *)(qry->targetList),
rt_index,
sublevels_up))
return TRUE;
if (rangeTableEntry_used(
(Node *)(qry->qual),
rt_index,
sublevels_up))
return TRUE;
if (rangeTableEntry_used(
(Node *)(qry->havingQual),
rt_index,
sublevels_up))
return TRUE;
return FALSE;
}
break;
default:
elog(NOTICE, "unknown node tag %d in rangeTableEntry_used()", nodeTag(node));
elog(NOTICE, "Node is: %s", nodeToString(node));
break;
}
return FALSE;
}
/*
* attribute_used -
* Check if a specific attribute number of a RTE is used
* somewhere in the query
*/
static bool
attribute_used(Node *node, int rt_index, int attno, int sublevels_up)
{
if (node == NULL)
return FALSE;
switch(nodeTag(node)) {
case T_TargetEntry:
{
TargetEntry *tle = (TargetEntry *)node;
return attribute_used(
(Node *)(tle->expr),
rt_index,
attno,
sublevels_up);
}
break;
case T_Aggref:
{
Aggref *aggref = (Aggref *)node;
return attribute_used(
(Node *)(aggref->target),
rt_index,
attno,
sublevels_up);
}
break;
case T_GroupClause:
return FALSE;
case T_Expr:
{
Expr *exp = (Expr *)node;
return attribute_used(
(Node *)(exp->args),
rt_index,
attno,
sublevels_up);
}
break;
case T_Iter:
{
Iter *iter = (Iter *)node;
return attribute_used(
(Node *)(iter->iterexpr),
rt_index,
attno,
sublevels_up);
}
break;
case T_ArrayRef:
{
ArrayRef *ref = (ArrayRef *)node;
if (attribute_used(
(Node *)(ref->refupperindexpr),
rt_index,
attno,
sublevels_up))
return TRUE;
if (attribute_used(
(Node *)(ref->reflowerindexpr),
rt_index,
attno,
sublevels_up))
return TRUE;
if (attribute_used(
(Node *)(ref->refexpr),
rt_index,
attno,
sublevels_up))
return TRUE;
if (attribute_used(
(Node *)(ref->refassgnexpr),
rt_index,
attno,
sublevels_up))
return TRUE;
return FALSE;
}
break;
case T_Var:
{
Var *var = (Var *)node;
if (var->varlevelsup == sublevels_up)
return var->varno == rt_index;
else
return FALSE;
}
break;
case T_Param:
return FALSE;
case T_Const:
return FALSE;
case T_List:
{
List *l;
foreach (l, (List *)node) {
if (attribute_used(
(Node *)lfirst(l),
rt_index,
attno,
sublevels_up))
return TRUE;
}
return FALSE;
}
break;
case T_SubLink:
{
SubLink *sub = (SubLink *)node;
if (attribute_used(
(Node *)(sub->lefthand),
rt_index,
attno,
sublevels_up))
return TRUE;
if (attribute_used(
(Node *)(sub->subselect),
rt_index,
attno,
sublevels_up + 1))
return TRUE;
return FALSE;
}
break;
case T_Query:
{
Query *qry = (Query *)node;
if (attribute_used(
(Node *)(qry->targetList),
rt_index,
attno,
sublevels_up))
return TRUE;
if (attribute_used(
(Node *)(qry->qual),
rt_index,
attno,
sublevels_up))
return TRUE;
if (attribute_used(
(Node *)(qry->havingQual),
rt_index,
attno,
sublevels_up))
return TRUE;
return FALSE;
}
break;
default:
elog(NOTICE, "unknown node tag %d in attribute_used()", nodeTag(node));
elog(NOTICE, "Node is: %s", nodeToString(node));
break;
}
return FALSE;
}
/*
* modifyAggrefUplevel -
* In the newly created sublink for an aggregate column used in
* the qualification, we must adjust the varlevelsup in all the
* var nodes.
*/
static void
modifyAggrefUplevel(Node *node)
{
if (node == NULL)
return;
switch(nodeTag(node)) {
case T_TargetEntry:
{
TargetEntry *tle = (TargetEntry *)node;
modifyAggrefUplevel(
(Node *)(tle->expr));
}
break;
case T_Aggref:
{
Aggref *aggref = (Aggref *)node;
modifyAggrefUplevel(
(Node *)(aggref->target));
}
break;
case T_Expr:
{
Expr *exp = (Expr *)node;
modifyAggrefUplevel(
(Node *)(exp->args));
}
break;
case T_Iter:
{
Iter *iter = (Iter *)node;
modifyAggrefUplevel(
(Node *)(iter->iterexpr));
}
break;
case T_ArrayRef:
{
ArrayRef *ref = (ArrayRef *)node;
modifyAggrefUplevel(
(Node *)(ref->refupperindexpr));
modifyAggrefUplevel(
(Node *)(ref->reflowerindexpr));
modifyAggrefUplevel(
(Node *)(ref->refexpr));
modifyAggrefUplevel(
(Node *)(ref->refassgnexpr));
}
break;
case T_Var:
{
Var *var = (Var *)node;
var->varlevelsup++;
}
break;
case T_Param:
break;
case T_Const:
break;
case T_List:
{
List *l;
foreach (l, (List *)node)
modifyAggrefUplevel(
(Node *)lfirst(l));
}
break;
case T_SubLink:
{
SubLink *sub = (SubLink *)node;
modifyAggrefUplevel(
(Node *)(sub->lefthand));
modifyAggrefUplevel(
(Node *)(sub->oper));
modifyAggrefUplevel(
(Node *)(sub->subselect));
}
break;
case T_Query:
{
Query *qry = (Query *)node;
modifyAggrefUplevel(
(Node *)(qry->targetList));
modifyAggrefUplevel(
(Node *)(qry->qual));
modifyAggrefUplevel(
(Node *)(qry->havingQual));
}
break;
default:
elog(NOTICE, "unknown node tag %d in modifyAggrefUplevel()", nodeTag(node));
elog(NOTICE, "Node is: %s", nodeToString(node));
break;
}
}
/*
* modifyAggrefChangeVarnodes -
* Change the var nodes in a sublink created for an aggregate column
* used in the qualification that is subject of the aggregate
* function to point to the correct local RTE.
*/
static void
modifyAggrefChangeVarnodes(Node **nodePtr, int rt_index, int new_index, int sublevels_up)
{
Node *node = *nodePtr;
if (node == NULL)
return;
switch(nodeTag(node)) {
case T_TargetEntry:
{
TargetEntry *tle = (TargetEntry *)node;
modifyAggrefChangeVarnodes(
(Node **)(&(tle->expr)),
rt_index,
new_index,
sublevels_up);
}
break;
case T_Aggref:
{
Aggref *aggref = (Aggref *)node;
modifyAggrefChangeVarnodes(
(Node **)(&(aggref->target)),
rt_index,
new_index,
sublevels_up);
}
break;
case T_GroupClause:
break;
case T_Expr:
{
Expr *exp = (Expr *)node;
modifyAggrefChangeVarnodes(
(Node **)(&(exp->args)),
rt_index,
new_index,
sublevels_up);
}
break;
case T_Iter:
{
Iter *iter = (Iter *)node;
modifyAggrefChangeVarnodes(
(Node **)(&(iter->iterexpr)),
rt_index,
new_index,
sublevels_up);
}
break;
case T_ArrayRef:
{
ArrayRef *ref = (ArrayRef *)node;
modifyAggrefChangeVarnodes(
(Node **)(&(ref->refupperindexpr)),
rt_index,
new_index,
sublevels_up);
modifyAggrefChangeVarnodes(
(Node **)(&(ref->reflowerindexpr)),
rt_index,
new_index,
sublevels_up);
modifyAggrefChangeVarnodes(
(Node **)(&(ref->refexpr)),
rt_index,
new_index,
sublevels_up);
modifyAggrefChangeVarnodes(
(Node **)(&(ref->refassgnexpr)),
rt_index,
new_index,
sublevels_up);
}
break;
case T_Var:
{
Var *var = (Var *)node;
if (var->varlevelsup == sublevels_up &&
var->varno == rt_index) {
var = copyObject(var);
var->varno = new_index;
var->varnoold = new_index;
var->varlevelsup = 0;
*nodePtr = (Node *)var;
}
}
break;
case T_Param:
break;
case T_Const:
break;
case T_List:
{
List *l;
foreach (l, (List *)node)
modifyAggrefChangeVarnodes(
(Node **)(&lfirst(l)),
rt_index,
new_index,
sublevels_up);
}
break;
case T_SubLink:
{
SubLink *sub = (SubLink *)node;
modifyAggrefChangeVarnodes(
(Node **)(&(sub->lefthand)),
rt_index,
new_index,
sublevels_up);
modifyAggrefChangeVarnodes(
(Node **)(&(sub->oper)),
rt_index,
new_index,
sublevels_up);
modifyAggrefChangeVarnodes(
(Node **)(&(sub->subselect)),
rt_index,
new_index,
sublevels_up + 1);
}
break;
case T_Query:
{
Query *qry = (Query *)node;
modifyAggrefChangeVarnodes(
(Node **)(&(qry->targetList)),
rt_index,
new_index,
sublevels_up);
modifyAggrefChangeVarnodes(
(Node **)(&(qry->qual)),
rt_index,
new_index,
sublevels_up);
modifyAggrefChangeVarnodes(
(Node **)(&(qry->havingQual)),
rt_index,
new_index,
sublevels_up);
}
break;
default:
elog(NOTICE, "unknown node tag %d in modifyAggrefChangeVarnodes()", nodeTag(node));
elog(NOTICE, "Node is: %s", nodeToString(node));
break;
}
}
/*
* modifyAggrefDropQual -
* remove the pure aggref clase from a qualification
*/
static void
modifyAggrefDropQual(Node **nodePtr, Node *orignode, Expr *expr)
{
Node *node = *nodePtr;
if (node == NULL)
return;
switch(nodeTag(node)) {
case T_Var:
break;
case T_Aggref:
{
Aggref *aggref = (Aggref *)node;
Aggref *oaggref = (Aggref *)orignode;
modifyAggrefDropQual(
(Node **)(&(aggref->target)),
(Node *)(oaggref->target),
expr);
}
break;
case T_Param:
break;
case T_Const:
break;
case T_GroupClause:
break;
case T_Expr:
{
Expr *this_expr = (Expr *)node;
Expr *orig_expr = (Expr *)orignode;
if (orig_expr == expr) {
Const *ctrue;
if (expr->typeOid != BOOLOID)
elog(ERROR,
"aggregate expression in qualification isn't of type bool");
ctrue = makeNode(Const);
ctrue->consttype = BOOLOID;
ctrue->constlen = 1;
ctrue->constisnull = FALSE;
ctrue->constvalue = (Datum)TRUE;
ctrue->constbyval = TRUE;
*nodePtr = (Node *)ctrue;
}
else
modifyAggrefDropQual(
(Node **)(&(this_expr->args)),
(Node *)(orig_expr->args),
expr);
}
break;
case T_Iter:
{
Iter *iter = (Iter *)node;
Iter *oiter = (Iter *)orignode;
modifyAggrefDropQual(
(Node **)(&(iter->iterexpr)),
(Node *)(oiter->iterexpr),
expr);
}
break;
case T_ArrayRef:
{
ArrayRef *ref = (ArrayRef *)node;
ArrayRef *oref = (ArrayRef *)orignode;
modifyAggrefDropQual(
(Node **)(&(ref->refupperindexpr)),
(Node *)(oref->refupperindexpr),
expr);
modifyAggrefDropQual(
(Node **)(&(ref->reflowerindexpr)),
(Node *)(oref->reflowerindexpr),
expr);
modifyAggrefDropQual(
(Node **)(&(ref->refexpr)),
(Node *)(oref->refexpr),
expr);
modifyAggrefDropQual(
(Node **)(&(ref->refassgnexpr)),
(Node *)(oref->refassgnexpr),
expr);
}
break;
case T_List:
{
List *l;
List *ol = (List *)orignode;
int li = 0;
foreach (l, (List *)node) {
modifyAggrefDropQual(
(Node **)(&(lfirst(l))),
(Node *)nth(li, ol),
expr);
li++;
}
}
break;
case T_SubLink:
{
SubLink *sub = (SubLink *)node;
SubLink *osub = (SubLink *)orignode;
modifyAggrefDropQual(
(Node **)(&(sub->subselect)),
(Node *)(osub->subselect),
expr);
}
break;
case T_Query:
{
Query *qry = (Query *)node;
Query *oqry = (Query *)orignode;
modifyAggrefDropQual(
(Node **)(&(qry->qual)),
(Node *)(oqry->qual),
expr);
modifyAggrefDropQual(
(Node **)(&(qry->havingQual)),
(Node *)(oqry->havingQual),
expr);
}
break;
default:
elog(NOTICE, "unknown node tag %d in modifyAggrefDropQual()", nodeTag(node));
elog(NOTICE, "Node is: %s", nodeToString(node));
break;
}
}
/*
* modifyAggrefMakeSublink -
* Create a sublink node for a qualification expression that
* uses an aggregate column of a view
*/
static SubLink *
modifyAggrefMakeSublink(Expr *origexp, Query *parsetree)
{
SubLink *sublink;
Query *subquery;
Node *subqual;
RangeTblEntry *rte;
Aggref *aggref;
Var *target;
TargetEntry *tle;
Resdom *resdom;
Expr *exp = copyObject(origexp);
if (nodeTag(nth(0, exp->args)) == T_Aggref)
{
if (nodeTag(nth(1, exp->args)) == T_Aggref)
elog(ERROR, "rewrite: comparision of 2 aggregate columns not supported");
else
elog(ERROR, "rewrite: aggregate column of view must be at rigth side in qual");
}
aggref = (Aggref *)nth(1, exp->args);
target = (Var *)(aggref->target);
rte = (RangeTblEntry *)nth(target->varno - 1, parsetree->rtable);
tle = makeNode(TargetEntry);
resdom = makeNode(Resdom);
aggref->usenulls = TRUE;
resdom->resno = 1;
resdom->restype = ((Oper *)(exp->oper))->opresulttype;
resdom->restypmod = -1;
resdom->resname = pstrdup("<noname>");
resdom->reskey = 0;
resdom->reskeyop = 0;
resdom->resjunk = false;
tle->resdom = resdom;
tle->expr = (Node *)aggref;
subqual = copyObject(parsetree->qual);
modifyAggrefDropQual((Node **)&subqual, (Node *)parsetree->qual, origexp);
sublink = makeNode(SubLink);
sublink->subLinkType = EXPR_SUBLINK;
sublink->useor = FALSE;
sublink->lefthand = lappend(NIL, copyObject(lfirst(exp->args)));
sublink->oper = lappend(NIL, copyObject(exp));
sublink->subselect = NULL;
subquery = makeNode(Query);
sublink->subselect = (Node *)subquery;
subquery->commandType = CMD_SELECT;
subquery->utilityStmt = NULL;
subquery->resultRelation = 0;
subquery->into = NULL;
subquery->isPortal = FALSE;
subquery->isBinary = FALSE;
subquery->isTemp = FALSE;
subquery->unionall = FALSE;
subquery->uniqueFlag = NULL;
subquery->sortClause = NULL;
subquery->rtable = lappend(NIL, rte);
subquery->targetList = lappend(NIL, tle);
subquery->qual = subqual;
subquery->groupClause = NIL;
subquery->havingQual = NULL;
subquery->hasAggs = TRUE;
subquery->hasSubLinks = FALSE;
subquery->unionClause = NULL;
modifyAggrefUplevel((Node *)sublink);
modifyAggrefChangeVarnodes((Node **)&(sublink->lefthand), target->varno,
1, target->varlevelsup);
modifyAggrefChangeVarnodes((Node **)&(sublink->oper), target->varno,
1, target->varlevelsup);
modifyAggrefChangeVarnodes((Node **)&(sublink->subselect), target->varno,
1, target->varlevelsup);
return sublink;
}
/*
* modifyAggrefQual -
* Search for qualification expressions that contain aggregate
* functions and substiture them by sublinks. These expressions
* originally come from qualifications that use aggregate columns
* of a view.
*/
static void
modifyAggrefQual(Node **nodePtr, Query *parsetree)
{
Node *node = *nodePtr;
if (node == NULL)
return;
switch(nodeTag(node)) {
case T_Var:
break;
case T_Param:
break;
case T_Const:
break;
case T_GroupClause:
break;
case T_Expr:
{
Expr *exp = (Expr *)node;
SubLink *sub;
if (length(exp->args) != 2) {
modifyAggrefQual(
(Node **)(&(exp->args)),
parsetree);
break;
}
if (nodeTag(nth(0, exp->args)) != T_Aggref &&
nodeTag(nth(1, exp->args)) != T_Aggref) {
modifyAggrefQual(
(Node **)(&(exp->args)),
parsetree);
break;
}
sub = modifyAggrefMakeSublink(exp,
parsetree);
*nodePtr = (Node *)sub;
parsetree->hasSubLinks = TRUE;
}
break;
case T_CaseExpr:
{
/* We're calling recursively,
* and this routine knows how to handle lists
* so let it do the work to handle the WHEN clauses... */
modifyAggrefQual(
(Node **)(&(((CaseExpr *)node)->args)),
parsetree);
modifyAggrefQual(
(Node **)(&(((CaseExpr *)node)->defresult)),
parsetree);
}
break;
case T_CaseWhen:
{
modifyAggrefQual(
(Node **)(&(((CaseWhen *)node)->expr)),
parsetree);
modifyAggrefQual(
(Node **)(&(((CaseWhen *)node)->result)),
parsetree);
}
break;
case T_Iter:
{
Iter *iter = (Iter *)node;
modifyAggrefQual(
(Node **)(&(iter->iterexpr)),
parsetree);
}
break;
case T_ArrayRef:
{
ArrayRef *ref = (ArrayRef *)node;
modifyAggrefQual(
(Node **)(&(ref->refupperindexpr)),
parsetree);
modifyAggrefQual(
(Node **)(&(ref->reflowerindexpr)),
parsetree);
modifyAggrefQual(
(Node **)(&(ref->refexpr)),
parsetree);
modifyAggrefQual(
(Node **)(&(ref->refassgnexpr)),
parsetree);
}
break;
case T_List:
{
List *l;
foreach (l, (List *)node)
modifyAggrefQual(
(Node **)(&(lfirst(l))),
parsetree);
}
break;
case T_SubLink:
{
SubLink *sub = (SubLink *)node;
modifyAggrefQual(
(Node **)(&(sub->subselect)),
(Query *)(sub->subselect));
}
break;
case T_Query:
{
Query *qry = (Query *)node;
modifyAggrefQual(
(Node **)(&(qry->qual)),
parsetree);
modifyAggrefQual(
(Node **)(&(qry->havingQual)),
parsetree);
}
break;
default:
elog(NOTICE, "unknown node tag %d in modifyAggrefQual()", nodeTag(node));
elog(NOTICE, "Node is: %s", nodeToString(node));
break;
}
}
/*
* checkQueryHasAggs -
* Queries marked hasAggs might not have them any longer after
* rewriting. Check it.
*/
static bool
checkQueryHasAggs(Node *node)
{
if (node == NULL)
return FALSE;
switch(nodeTag(node)) {
case T_TargetEntry:
{
TargetEntry *tle = (TargetEntry *)node;
return checkQueryHasAggs((Node *)(tle->expr));
}
break;
case T_Aggref:
return TRUE;
case T_Expr:
{
Expr *exp = (Expr *)node;
return checkQueryHasAggs((Node *)(exp->args));
}
break;
case T_Iter:
{
Iter *iter = (Iter *)node;
return checkQueryHasAggs((Node *)(iter->iterexpr));
}
break;
case T_ArrayRef:
{
ArrayRef *ref = (ArrayRef *)node;
if (checkQueryHasAggs((Node *)(ref->refupperindexpr)))
return TRUE;
if (checkQueryHasAggs((Node *)(ref->reflowerindexpr)))
return TRUE;
if (checkQueryHasAggs((Node *)(ref->refexpr)))
return TRUE;
if (checkQueryHasAggs((Node *)(ref->refassgnexpr)))
return TRUE;
return FALSE;
}
break;
case T_Var:
return FALSE;
case T_Param:
return FALSE;
case T_Const:
return FALSE;
case T_List:
{
List *l;
foreach (l, (List *)node) {
if (checkQueryHasAggs((Node *)lfirst(l)))
return TRUE;
}
return FALSE;
}
break;
case T_CaseExpr:
{
CaseExpr *exp = (CaseExpr *)node;
if (checkQueryHasAggs((Node *)(exp->args)))
return TRUE;
if (checkQueryHasAggs((Node *)(exp->defresult)))
return TRUE;
return FALSE;
}
break;
case T_CaseWhen:
{
CaseWhen *when = (CaseWhen *)node;
if (checkQueryHasAggs((Node *)(when->expr)))
return TRUE;
if (checkQueryHasAggs((Node *)(when->result)))
return TRUE;
return FALSE;
}
break;
default:
elog(NOTICE, "unknown node tag %d in checkQueryHasAggs()", nodeTag(node));
elog(NOTICE, "Node is: %s", nodeToString(node));
break;
}
return FALSE;
}
/*
* checkQueryHasSubLink -
* Queries marked hasAggs might not have them any longer after
* rewriting. Check it.
*/
static bool
checkQueryHasSubLink(Node *node)
{
if (node == NULL)
return FALSE;
switch(nodeTag(node)) {
case T_TargetEntry:
{
TargetEntry *tle = (TargetEntry *)node;
return checkQueryHasSubLink((Node *)(tle->expr));
}
break;
case T_Aggref:
return TRUE;
case T_Expr:
{
Expr *exp = (Expr *)node;
return checkQueryHasSubLink((Node *)(exp->args));
}
break;
case T_Iter:
{
Iter *iter = (Iter *)node;
return checkQueryHasSubLink((Node *)(iter->iterexpr));
}
break;
case T_ArrayRef:
{
ArrayRef *ref = (ArrayRef *)node;
if (checkQueryHasSubLink((Node *)(ref->refupperindexpr)))
return TRUE;
if (checkQueryHasSubLink((Node *)(ref->reflowerindexpr)))
return TRUE;
if (checkQueryHasSubLink((Node *)(ref->refexpr)))
return TRUE;
if (checkQueryHasSubLink((Node *)(ref->refassgnexpr)))
return TRUE;
return FALSE;
}
break;
case T_Var:
return FALSE;
case T_Param:
return FALSE;
case T_Const:
return FALSE;
case T_List:
{
List *l;
foreach (l, (List *)node) {
if (checkQueryHasSubLink((Node *)lfirst(l)))
return TRUE;
}
return FALSE;
}
break;
case T_CaseExpr:
{
CaseExpr *exp = (CaseExpr *)node;
if (checkQueryHasSubLink((Node *)(exp->args)))
return TRUE;
if (checkQueryHasSubLink((Node *)(exp->defresult)))
return TRUE;
return FALSE;
}
break;
case T_CaseWhen:
{
CaseWhen *when = (CaseWhen *)node;
if (checkQueryHasSubLink((Node *)(when->expr)))
return TRUE;
if (checkQueryHasSubLink((Node *)(when->result)))
return TRUE;
return FALSE;
}
break;
case T_SubLink:
return TRUE;
default:
elog(NOTICE, "unknown node tag %d in checkQueryHasSubLink()", nodeTag(node));
elog(NOTICE, "Node is: %s", nodeToString(node));
break;
}
return FALSE;
}
static Node *
FindMatchingTLEntry(List *tlist, char *e_attname)
{
List *i;
foreach(i, tlist)
{
TargetEntry *tle = lfirst(i);
char *resname;
resname = tle->resdom->resname;
if (!strcmp(e_attname, resname))
return (tle->expr);
}
return NULL;
}
static Node *
make_null(Oid type)
{
Const *c = makeNode(Const);
c->consttype = type;
c->constlen = get_typlen(type);
c->constvalue = PointerGetDatum(NULL);
c->constisnull = true;
c->constbyval = get_typbyval(type);
return (Node *) c;
}
static void
apply_RIR_adjust_sublevel(Node *node, int sublevels_up)
{
if (node == NULL)
return;
switch(nodeTag(node)) {
case T_TargetEntry:
{
TargetEntry *tle = (TargetEntry *)node;
apply_RIR_adjust_sublevel(
(Node *)(tle->expr),
sublevels_up);
}
break;
case T_Aggref:
{
Aggref *aggref = (Aggref *)node;
apply_RIR_adjust_sublevel(
(Node *)(aggref->target),
sublevels_up);
}
break;
case T_GroupClause:
break;
case T_Expr:
{
Expr *exp = (Expr *)node;
apply_RIR_adjust_sublevel(
(Node *)(exp->args),
sublevels_up);
}
break;
case T_Iter:
{
Iter *iter = (Iter *)node;
apply_RIR_adjust_sublevel(
(Node *)(iter->iterexpr),
sublevels_up);
}
break;
case T_ArrayRef:
{
ArrayRef *ref = (ArrayRef *)node;
apply_RIR_adjust_sublevel(
(Node *)(ref->refupperindexpr),
sublevels_up);
apply_RIR_adjust_sublevel(
(Node *)(ref->reflowerindexpr),
sublevels_up);
apply_RIR_adjust_sublevel(
(Node *)(ref->refexpr),
sublevels_up);
apply_RIR_adjust_sublevel(
(Node *)(ref->refassgnexpr),
sublevels_up);
}
break;
case T_Var:
{
Var *var = (Var *)node;
var->varlevelsup = sublevels_up;
}
break;
case T_Param:
break;
case T_Const:
break;
case T_List:
{
List *l;
foreach (l, (List *)node) {
apply_RIR_adjust_sublevel(
(Node *)lfirst(l),
sublevels_up);
}
}
break;
case T_CaseExpr:
{
CaseExpr *exp = (CaseExpr *)node;
apply_RIR_adjust_sublevel(
(Node *)(exp->args),
sublevels_up);
apply_RIR_adjust_sublevel(
(Node *)(exp->defresult),
sublevels_up);
}
break;
case T_CaseWhen:
{
CaseWhen *exp = (CaseWhen *)node;
apply_RIR_adjust_sublevel(
(Node *)(exp->expr),
sublevels_up);
apply_RIR_adjust_sublevel(
(Node *)(exp->result),
sublevels_up);
}
break;
default:
elog(NOTICE, "unknown node tag %d in attribute_used()", nodeTag(node));
elog(NOTICE, "Node is: %s", nodeToString(node));
break;
}
}
static void
apply_RIR_view(Node **nodePtr, int rt_index, RangeTblEntry *rte, List *tlist, int *modified, int sublevels_up)
{
Node *node = *nodePtr;
if (node == NULL)
return;
switch(nodeTag(node)) {
case T_TargetEntry:
{
TargetEntry *tle = (TargetEntry *)node;
apply_RIR_view(
(Node **)(&(tle->expr)),
rt_index,
rte,
tlist,
modified,
sublevels_up);
}
break;
case T_Aggref:
{
Aggref *aggref = (Aggref *)node;
apply_RIR_view(
(Node **)(&(aggref->target)),
rt_index,
rte,
tlist,
modified,
sublevels_up);
}
break;
case T_GroupClause:
break;
case T_Expr:
{
Expr *exp = (Expr *)node;
apply_RIR_view(
(Node **)(&(exp->args)),
rt_index,
rte,
tlist,
modified,
sublevels_up);
}
break;
case T_Iter:
{
Iter *iter = (Iter *)node;
apply_RIR_view(
(Node **)(&(iter->iterexpr)),
rt_index,
rte,
tlist,
modified,
sublevels_up);
}
break;
case T_ArrayRef:
{
ArrayRef *ref = (ArrayRef *)node;
apply_RIR_view(
(Node **)(&(ref->refupperindexpr)),
rt_index,
rte,
tlist,
modified,
sublevels_up);
apply_RIR_view(
(Node **)(&(ref->reflowerindexpr)),
rt_index,
rte,
tlist,
modified,
sublevels_up);
apply_RIR_view(
(Node **)(&(ref->refexpr)),
rt_index,
rte,
tlist,
modified,
sublevels_up);
apply_RIR_view(
(Node **)(&(ref->refassgnexpr)),
rt_index,
rte,
tlist,
modified,
sublevels_up);
}
break;
case T_Var:
{
Var *var = (Var *)node;
if (var->varlevelsup == sublevels_up &&
var->varno == rt_index) {
Node *exp;
if (var->varattno < 0)
elog(ERROR, "system column %s not available - %s is a view", get_attname(rte->relid, var->varattno), rte->relname);
exp = FindMatchingTLEntry(
tlist,
get_attname(rte->relid,
var->varattno));
if (exp == NULL) {
*nodePtr = make_null(var->vartype);
return;
}
exp = copyObject(exp);
if (var->varlevelsup > 0)
apply_RIR_adjust_sublevel(exp, var->varlevelsup);
*nodePtr = exp;
*modified = TRUE;
}
}
break;
case T_Param:
break;
case T_Const:
break;
case T_List:
{
List *l;
foreach (l, (List *)node)
apply_RIR_view(
(Node **)(&(lfirst(l))),
rt_index,
rte,
tlist,
modified,
sublevels_up);
}
break;
case T_SubLink:
{
SubLink *sub = (SubLink *)node;
List *tmp_lefthand, *tmp_oper;
apply_RIR_view(
(Node **)(&(sub->lefthand)),
rt_index,
rte,
tlist,
modified,
sublevels_up);
apply_RIR_view(
(Node **)(&(sub->subselect)),
rt_index,
rte,
tlist,
modified,
sublevels_up + 1);
/***S*I***/
tmp_lefthand = sub->lefthand;
foreach(tmp_oper, sub->oper)
{
lfirst(((Expr *) lfirst(tmp_oper))->args) =
lfirst(tmp_lefthand);
tmp_lefthand = lnext(tmp_lefthand);
}
}
break;
case T_Query:
{
Query *qry = (Query *)node;
apply_RIR_view(
(Node **)(&(qry->targetList)),
rt_index,
rte,
tlist,
modified,
sublevels_up);
apply_RIR_view(
(Node **)(&(qry->qual)),
rt_index,
rte,
tlist,
modified,
sublevels_up);
apply_RIR_view(
(Node **)(&(qry->havingQual)),
rt_index,
rte,
tlist,
modified,
sublevels_up);
}
break;
case T_CaseExpr:
{
CaseExpr *exp = (CaseExpr *)node;
apply_RIR_view(
(Node **)(&(exp->args)),
rt_index,
rte,
tlist,
modified,
sublevels_up);
apply_RIR_view(
(Node **)(&(exp->defresult)),
rt_index,
rte,
tlist,
modified,
sublevels_up);
}
break;
case T_CaseWhen:
{
CaseWhen *exp = (CaseWhen *)node;
apply_RIR_view(
(Node **)(&(exp->expr)),
rt_index,
rte,
tlist,
modified,
sublevels_up);
apply_RIR_view(
(Node **)(&(exp->result)),
rt_index,
rte,
tlist,
modified,
sublevels_up);
}
break;
default:
elog(NOTICE, "unknown node tag %d in apply_RIR_view()", nodeTag(node));
elog(NOTICE, "Node is: %s", nodeToString(node));
break;
}
}
extern void CheckSelectForUpdate(Query *rule_action); /* in analyze.c */
static void
ApplyRetrieveRule(Query *parsetree,
RewriteRule *rule,
int rt_index,
int relation_level,
Relation relation,
int *modified)
{
Query *rule_action = NULL;
Node *rule_qual;
List *rtable,
*rt,
*l;
int nothing,
rt_length;
int badsql = FALSE;
rule_qual = rule->qual;
if (rule->actions)
{
if (length(rule->actions) > 1) /* ??? because we don't handle
* rules with more than one
* action? -ay */
return;
rule_action = copyObject(lfirst(rule->actions));
nothing = FALSE;
}
else
nothing = TRUE;
rtable = copyObject(parsetree->rtable);
foreach(rt, rtable)
{
RangeTblEntry *rte = lfirst(rt);
/*
* this is to prevent add_missing_vars_to_base_rels() from adding
* a bogus entry to the new target list.
*/
rte->inFromCl = false;
}
rt_length = length(rtable);
rtable = nconc(rtable, copyObject(rule_action->rtable));
parsetree->rtable = rtable;
/* FOR UPDATE of view... */
foreach (l, parsetree->rowMark)
{
if (((RowMark*)lfirst(l))->rti == rt_index)
break;
}
if (l != NULL) /* oh, hell -:) */
{
RowMark *newrm;
Index rti = 1;
List *l2;
CheckSelectForUpdate(rule_action);
/*
* We believe that rt_index is VIEW - nothing should be
* marked for VIEW, but ACL check must be done.
* As for real tables of VIEW - their rows must be marked, but
* we have to skip ACL check for them.
*/
((RowMark*)lfirst(l))->info &= ~ROW_MARK_FOR_UPDATE;
foreach (l2, rule_action->rtable)
{
/*
* RTable of VIEW has two entries of VIEW itself -
* we use relid to skip them.
*/
if (relation->rd_id != ((RangeTblEntry*)lfirst(l2))->relid)
{
newrm = makeNode(RowMark);
newrm->rti = rti + rt_length;
newrm->info = ROW_MARK_FOR_UPDATE;
lnext(l) = lcons(newrm, lnext(l));
l = lnext(l);
}
rti++;
}
}
rule_action->rtable = rtable;
OffsetVarNodes((Node *) rule_qual, rt_length, 0);
OffsetVarNodes((Node *) rule_action, rt_length, 0);
ChangeVarNodes((Node *) rule_qual,
PRS2_CURRENT_VARNO + rt_length, rt_index, 0);
ChangeVarNodes((Node *) rule_action,
PRS2_CURRENT_VARNO + rt_length, rt_index, 0);
if (relation_level)
{
apply_RIR_view((Node **) &parsetree, rt_index,
(RangeTblEntry *)nth(rt_index - 1, rtable),
rule_action->targetList, modified, 0);
apply_RIR_view((Node **) &rule_action, rt_index,
(RangeTblEntry *)nth(rt_index - 1, rtable),
rule_action->targetList, modified, 0);
}
else
{
HandleRIRAttributeRule(parsetree, rtable, rule_action->targetList,
rt_index, rule->attrno, modified, &badsql);
}
if (*modified && !badsql) {
AddQual(parsetree, rule_action->qual);
AddGroupClause(parsetree, rule_action->groupClause,
rule_action->targetList);
AddHavingQual(parsetree, rule_action->havingQual);
parsetree->hasAggs = (rule_action->hasAggs || parsetree->hasAggs);
parsetree->hasSubLinks = (rule_action->hasSubLinks || parsetree->hasSubLinks);
}
}
static void
fireRIRonSubselect(Node *node)
{
if (node == NULL)
return;
switch(nodeTag(node)) {
case T_TargetEntry:
{
TargetEntry *tle = (TargetEntry *)node;
fireRIRonSubselect(
(Node *)(tle->expr));
}
break;
case T_Aggref:
{
Aggref *aggref = (Aggref *)node;
fireRIRonSubselect(
(Node *)(aggref->target));
}
break;
case T_GroupClause:
break;
case T_Expr:
{
Expr *exp = (Expr *)node;
fireRIRonSubselect(
(Node *)(exp->args));
}
break;
case T_Iter:
{
Iter *iter = (Iter *)node;
fireRIRonSubselect(
(Node *)(iter->iterexpr));
}
break;
case T_ArrayRef:
{
ArrayRef *ref = (ArrayRef *)node;
fireRIRonSubselect(
(Node *)(ref->refupperindexpr));
fireRIRonSubselect(
(Node *)(ref->reflowerindexpr));
fireRIRonSubselect(
(Node *)(ref->refexpr));
fireRIRonSubselect(
(Node *)(ref->refassgnexpr));
}
break;
case T_Var:
break;
case T_Param:
break;
case T_Const:
break;
case T_List:
{
List *l;
foreach (l, (List *)node)
fireRIRonSubselect(
(Node *)(lfirst(l)));
}
break;
case T_SubLink:
{
SubLink *sub = (SubLink *)node;
Query *qry;
fireRIRonSubselect(
(Node *)(sub->lefthand));
qry = fireRIRrules((Query *)(sub->subselect));
fireRIRonSubselect(
(Node *)qry);
sub->subselect = (Node *) qry;
}
break;
case T_CaseExpr:
{
CaseExpr *exp = (CaseExpr *)node;
fireRIRonSubselect(
(Node *)(exp->args));
fireRIRonSubselect(
(Node *)(exp->defresult));
}
break;
case T_CaseWhen:
{
CaseWhen *exp = (CaseWhen *)node;
fireRIRonSubselect(
(Node *)(exp->expr));
fireRIRonSubselect(
(Node *)(exp->result));
}
break;
case T_Query:
{
Query *qry = (Query *)node;
fireRIRonSubselect(
(Node *)(qry->targetList));
fireRIRonSubselect(
(Node *)(qry->qual));
fireRIRonSubselect(
(Node *)(qry->havingQual));
}
break;
default:
elog(NOTICE, "unknown node tag %d in fireRIRonSubselect()", nodeTag(node));
elog(NOTICE, "Node is: %s", nodeToString(node));
break;
}
}
/*
* fireRIRrules -
* Apply all RIR rules on each rangetable entry in a query
*/
static Query *
fireRIRrules(Query *parsetree)
{
int rt_index;
RangeTblEntry *rte;
Relation rel;
List *locks;
RuleLock *rules;
RewriteRule *rule;
RewriteRule RIRonly;
int modified;
int i;
List *l;
rt_index = 0;
while(rt_index < length(parsetree->rtable)) {
++rt_index;
rte = nth(rt_index - 1, parsetree->rtable);
if (!rangeTableEntry_used((Node *)parsetree, rt_index, 0))
{
/*
* Unused range table entries must not be marked as coming
* from a clause. Otherwise the planner will generate
* joins over relations that in fact shouldn't be scanned
* at all and the result will contain duplicates
*
* Jan
*
*/
rte->inFromCl = FALSE;
continue;
}
rel = heap_openr(rte->relname);
if (rel->rd_rules == NULL) {
heap_close(rel);
continue;
}
rules = rel->rd_rules;
locks = NIL;
/*
* Collect the RIR rules that we must apply
*/
for (i = 0; i < rules->numLocks; i++) {
rule = rules->rules[i];
if (rule->event != CMD_SELECT)
continue;
if (rule->attrno > 0 &&
!attribute_used((Node *)parsetree,
rt_index,
rule->attrno, 0))
continue;
locks = lappend(locks, rule);
}
/*
* Check permissions
*/
checkLockPerms(locks, parsetree, rt_index);
/*
* Now apply them
*/
foreach (l, locks) {
rule = lfirst(l);
RIRonly.event = rule->event;
RIRonly.attrno = rule->attrno;
RIRonly.qual = rule->qual;
RIRonly.actions = rule->actions;
ApplyRetrieveRule(parsetree,
&RIRonly,
rt_index,
RIRonly.attrno == -1,
rel,
&modified);
}
heap_close(rel);
}
fireRIRonSubselect((Node *) parsetree);
modifyAggrefQual((Node **) &(parsetree->qual), parsetree);
return parsetree;
}
/*
* idea is to fire regular rules first, then qualified instead
* rules and unqualified instead rules last. Any lemming is counted for.
*/
static List *
orderRules(List *locks)
{
List *regular = NIL;
List *instead_rules = NIL;
List *instead_qualified = NIL;
List *i;
foreach(i, locks)
{
RewriteRule *rule_lock = (RewriteRule *) lfirst(i);
if (rule_lock->isInstead)
{
if (rule_lock->qual == NULL)
instead_rules = lappend(instead_rules, rule_lock);
else
instead_qualified = lappend(instead_qualified, rule_lock);
}
else
regular = lappend(regular, rule_lock);
}
regular = nconc(regular, instead_qualified);
return nconc(regular, instead_rules);
}
static Query *
CopyAndAddQual(Query *parsetree,
List *actions,
Node *rule_qual,
int rt_index,
CmdType event)
{
Query *new_tree = (Query *) copyObject(parsetree);
Node *new_qual = NULL;
Query *rule_action = NULL;
if (actions)
rule_action = lfirst(actions);
if (rule_qual != NULL)
new_qual = (Node *) copyObject(rule_qual);
if (rule_action != NULL)
{
List *rtable;
int rt_length;
rtable = new_tree->rtable;
rt_length = length(rtable);
rtable = nconc(rtable, copyObject(rule_action->rtable));
new_tree->rtable = rtable;
OffsetVarNodes(new_qual, rt_length, 0);
ChangeVarNodes(new_qual, PRS2_CURRENT_VARNO + rt_length, rt_index, 0);
}
/* XXX -- where current doesn't work for instead nothing.... yet */
AddNotQual(new_tree, new_qual);
return new_tree;
}
/*
* fireRules -
* Iterate through rule locks applying rules.
* All rules create their own parsetrees. Instead rules
* with rule qualification save the original parsetree
* and add their negated qualification to it. Real instead
* rules finally throw away the original parsetree.
*
* remember: reality is for dead birds -- glass
*
*/
static List *
fireRules(Query *parsetree,
int rt_index,
CmdType event,
bool *instead_flag,
List *locks,
List **qual_products)
{
RewriteInfo *info;
List *results = NIL;
List *i;
/* choose rule to fire from list of rules */
if (locks == NIL)
{
return NIL;
}
locks = orderRules(locks); /* real instead rules last */
foreach(i, locks)
{
RewriteRule *rule_lock = (RewriteRule *) lfirst(i);
Node *qual,
*event_qual;
List *actions;
List *r;
/*
* Instead rules change the resultRelation of the query. So the
* permission checks on the initial resultRelation would never be
* done (this is normally done in the executor deep down). So we
* must do it here. The result relations resulting from earlier
* rewrites are already checked against the rules eventrelation
* owner (during matchLocks) and have the skipAcl flag set.
*/
if (rule_lock->isInstead &&
parsetree->commandType != CMD_SELECT)
{
RangeTblEntry *rte;
int32 acl_rc;
int32 reqperm;
switch (parsetree->commandType)
{
case CMD_INSERT:
reqperm = ACL_AP;
break;
default:
reqperm = ACL_WR;
break;
}
rte = (RangeTblEntry *) nth(parsetree->resultRelation - 1,
parsetree->rtable);
if (!rte->skipAcl)
{
acl_rc = pg_aclcheck(rte->relname,
GetPgUserName(), reqperm);
if (acl_rc != ACLCHECK_OK)
{
elog(ERROR, "%s: %s",
rte->relname,
aclcheck_error_strings[acl_rc]);
}
}
}
/* multiple rule action time */
*instead_flag = rule_lock->isInstead;
event_qual = rule_lock->qual;
actions = rule_lock->actions;
if (event_qual != NULL && *instead_flag)
{
Query *qual_product;
RewriteInfo qual_info;
/* ----------
* If there are instead rules with qualifications,
* the original query is still performed. But all
* the negated rule qualifications of the instead
* rules are added so it does it's actions only
* in cases where the rule quals of all instead
* rules are false. Think of it as the default
* action in a case. We save this in *qual_products
* so deepRewriteQuery() can add it to the query
* list after we mangled it up enough.
* ----------
*/
if (*qual_products == NIL)
qual_product = parsetree;
else
qual_product = (Query *) nth(0, *qual_products);
qual_info.event = qual_product->commandType;
qual_info.new_varno = length(qual_product->rtable) + 2;
qual_product = CopyAndAddQual(qual_product,
actions,
event_qual,
rt_index,
event);
qual_info.rule_action = qual_product;
if (event == CMD_INSERT || event == CMD_UPDATE)
FixNew(&qual_info, qual_product);
*qual_products = lappend(NIL, qual_product);
}
foreach(r, actions)
{
Query *rule_action = lfirst(r);
Node *rule_qual = copyObject(event_qual);
if (rule_action->commandType == CMD_NOTHING)
continue;
/*--------------------------------------------------
* We copy the qualifications of the parsetree
* to the action and vice versa. So force
* hasSubLinks if one of them has it.
*
* As of 6.4 only parsetree qualifications can
* have sublinks. If this changes, we must make
* this a node lookup at the end of rewriting.
*
* Jan
*--------------------------------------------------
*/
if (parsetree->hasSubLinks && !rule_action->hasSubLinks)
{
rule_action = copyObject(rule_action);
rule_action->hasSubLinks = TRUE;
}
if (!parsetree->hasSubLinks && rule_action->hasSubLinks)
{
parsetree->hasSubLinks = TRUE;
}
/*--------------------------------------------------
* Step 1:
* Rewrite current.attribute or current to tuple variable
* this appears to be done in parser?
*--------------------------------------------------
*/
info = gatherRewriteMeta(parsetree, rule_action, rule_qual,
rt_index, event, instead_flag);
/* handle escapable cases, or those handled by other code */
if (info->nothing)
{
if (*instead_flag)
return NIL;
else
continue;
}
if (info->action == info->event &&
info->event == CMD_SELECT)
continue;
/*
* Event Qualification forces copying of parsetree and
* splitting into two queries one w/rule_qual, one w/NOT
* rule_qual. Also add user query qual onto rule action
*/
qual = parsetree->qual;
AddQual(info->rule_action, qual);
if (info->rule_qual != NULL)
AddQual(info->rule_action, info->rule_qual);
/*--------------------------------------------------
* Step 2:
* Rewrite new.attribute w/ right hand side of target-list
* entry for appropriate field name in insert/update
*--------------------------------------------------
*/
if ((info->event == CMD_INSERT) || (info->event == CMD_UPDATE))
FixNew(info, parsetree);
/*--------------------------------------------------
* Step 3:
* rewriting due to retrieve rules
*--------------------------------------------------
*/
info->rule_action->rtable = info->rt;
/*
ProcessRetrieveQuery(info->rule_action, info->rt,
&orig_instead_flag, TRUE);
*/
/*--------------------------------------------------
* Step 4
* Simplify? hey, no algorithm for simplification... let
* the planner do it.
*--------------------------------------------------
*/
results = lappend(results, info->rule_action);
pfree(info);
}
/* ----------
* If this was an unqualified instead rule,
* throw away an eventually saved 'default' parsetree
* ----------
*/
if (event_qual == NULL && *instead_flag)
*qual_products = NIL;
}
return results;
}
static List *
RewriteQuery(Query *parsetree, bool *instead_flag, List **qual_products)
{
CmdType event;
List *product_queries = NIL;
int result_relation = 0;
RangeTblEntry *rt_entry;
Relation rt_entry_relation = NULL;
RuleLock *rt_entry_locks = NULL;
Assert(parsetree != NULL);
event = parsetree->commandType;
/*
* SELECT rules are handled later when we have all the
* queries that should get executed
*/
if (event == CMD_SELECT)
return NIL;
/*
* Utilities aren't rewritten at all - why is this here?
*/
if (event == CMD_UTILITY)
return NIL;
/*
* only for a delete may the targetlist be NULL
*/
if (event != CMD_DELETE)
Assert(parsetree->targetList != NULL);
result_relation = parsetree->resultRelation;
/*
* the statement is an update, insert or delete - fire rules
* on it.
*/
rt_entry = rt_fetch(result_relation, parsetree->rtable);
rt_entry_relation = heap_openr(rt_entry->relname);
rt_entry_locks = rt_entry_relation->rd_rules;
heap_close(rt_entry_relation);
if (rt_entry_locks != NULL)
{
List *locks = matchLocks(event, rt_entry_locks, result_relation, parsetree);
product_queries = fireRules(parsetree,
result_relation,
event,
instead_flag,
locks,
qual_products);
}
return product_queries;
}
/*
* to avoid infinite recursion, we restrict the number of times a query
* can be rewritten. Detecting cycles is left for the reader as an excercise.
*/
#ifndef REWRITE_INVOKE_MAX
#define REWRITE_INVOKE_MAX 10
#endif
static int numQueryRewriteInvoked = 0;
/*
* deepRewriteQuery -
* rewrites the query and apply the rules again on the queries rewritten
*/
static List *
deepRewriteQuery(Query *parsetree)
{
List *n;
List *rewritten = NIL;
List *result = NIL;
bool instead;
List *qual_products = NIL;
if (++numQueryRewriteInvoked > REWRITE_INVOKE_MAX)
{
elog(ERROR, "query rewritten %d times, may contain cycles",
numQueryRewriteInvoked - 1);
}
instead = FALSE;
result = RewriteQuery(parsetree, &instead, &qual_products);
foreach(n, result)
{
Query *pt = lfirst(n);
List *newstuff = NIL;
newstuff = deepRewriteQuery(pt);
if (newstuff != NIL)
rewritten = nconc(rewritten, newstuff);
}
/* ----------
* qual_products are the original query with the negated
* rule qualification of an instead rule
* ----------
*/
if (qual_products != NIL)
rewritten = nconc(rewritten, qual_products);
/* ----------
* The original query is appended last if not instead
* because update and delete rule actions might not do
* anything if they are invoked after the update or
* delete is performed. The command counter increment
* between the query execution makes the deleted (and
* maybe the updated) tuples disappear so the scans
* for them in the rule actions cannot find them.
* ----------
*/
if (!instead)
rewritten = lappend(rewritten, parsetree);
return rewritten;
}
/*
* QueryOneRewrite -
* rewrite one query
*/
static List *
QueryRewriteOne(Query *parsetree)
{
numQueryRewriteInvoked = 0;
/*
* take a deep breath and apply all the rewrite rules - ay
*/
return deepRewriteQuery(parsetree);
}
/* ----------
* RewritePreprocessQuery -
* adjust details in the parsetree, the rule system
* depends on
* ----------
*/
static void
RewritePreprocessQuery(Query *parsetree)
{
/* ----------
* if the query has a resultRelation, reassign the
* result domain numbers to the attribute numbers in the
* target relation. FixNew() depends on it when replacing
* *new* references in a rule action by the expressions
* from the rewritten query.
* ----------
*/
if (parsetree->resultRelation > 0)
{
RangeTblEntry *rte;
Relation rd;
List *tl;
TargetEntry *tle;
int resdomno;
rte = (RangeTblEntry *) nth(parsetree->resultRelation - 1,
parsetree->rtable);
rd = heap_openr(rte->relname);
foreach(tl, parsetree->targetList)
{
tle = (TargetEntry *) lfirst(tl);
resdomno = attnameAttNum(rd, tle->resdom->resname);
tle->resdom->resno = resdomno;
}
heap_close(rd);
}
}
/*
* BasicQueryRewrite -
* rewrite one query via query rewrite system, possibly returning 0
* or many queries
*/
static List *
BasicQueryRewrite(Query *parsetree)
{
List *querylist;
List *results = NIL;
List *l;
Query *query;
/*
* Step 1
*
* There still seems something broken with the resdom numbers
* so we reassign them first.
*/
RewritePreprocessQuery(parsetree);
/*
* Step 2
*
* Apply all non-SELECT rules possibly getting 0 or many queries
*/
querylist = QueryRewriteOne(parsetree);
/*
* Step 3
*
* Apply all the RIR rules on each query
*/
foreach (l, querylist) {
query = fireRIRrules((Query *)lfirst(l));
/*
* If the query was marked having aggregates, check if
* this is still true after rewriting. This check must get
* expanded when someday aggregates can appear somewhere
* else than in the targetlist or the having qual.
*/
if (query->hasAggs)
query->hasAggs = checkQueryHasAggs((Node *)(query->targetList))
| checkQueryHasAggs((Node *)(query->havingQual));
query->hasSubLinks = checkQueryHasSubLink((Node *)(query->qual))
| checkQueryHasSubLink((Node *)(query->havingQual));
results = lappend(results, query);
}
return results;
}
/*
* QueryRewrite -
* Primary entry point to the query rewriter.
* Rewrite one query via query rewrite system, possibly returning 0
* or many queries.
*
* NOTE: The code in QueryRewrite was formerly in pg_parse_and_plan(), and was
* moved here so that it would be invoked during EXPLAIN. The division of
* labor between this routine and BasicQueryRewrite is not obviously correct
* ... at least not to me ... tgl 5/99.
*/
List *
QueryRewrite(Query *parsetree)
{
List *rewritten,
*rewritten_item;
/***S*I***/
/* Rewrite Union, Intersect and Except Queries
* to normal Union Queries using IN and NOT IN subselects */
if (parsetree->intersectClause)
parsetree = Except_Intersect_Rewrite(parsetree);
/* Rewrite basic queries (retrieve, append, delete, replace) */
rewritten = BasicQueryRewrite(parsetree);
/*
* Rewrite the UNIONS.
*/
foreach (rewritten_item, rewritten)
{
Query *qry = (Query *) lfirst(rewritten_item);
List *union_result = NIL;
List *union_item;
foreach (union_item, qry->unionClause)
{
union_result = nconc(union_result,
BasicQueryRewrite((Query *) lfirst(union_item)));
}
qry->unionClause = union_result;
}
return rewritten;
}
/***S*I***/
/* This function takes two targetlists as arguments and checks if the
* targetlists are compatible (i.e. both select for the same number of
* attributes and the types are compatible */
void check_targetlists_are_compatible(List *prev_target, List *current_target)
{
List *tl, *next_target;
int prev_len = 0, next_len = 0;
foreach(tl, prev_target)
if (!((TargetEntry *) lfirst(tl))->resdom->resjunk)
prev_len++;
foreach(next_target, current_target)
if (!((TargetEntry *) lfirst(next_target))->resdom->resjunk)
next_len++;
if (prev_len != next_len)
elog(ERROR,"Each UNION | EXCEPT | INTERSECT query must have the same number of columns.");
foreach(next_target, current_target)
{
Oid itype;
Oid otype;
otype = ((TargetEntry *) lfirst(prev_target))->resdom->restype;
itype = ((TargetEntry *) lfirst(next_target))->resdom->restype;
/* one or both is a NULL column? then don't convert... */
if (otype == InvalidOid)
{
/* propagate a known type forward, if available */
if (itype != InvalidOid)
((TargetEntry *) lfirst(prev_target))->resdom->restype = itype;
#ifdef NOT_USED
else
{
((TargetEntry *) lfirst(prev_target))->resdom->restype = UNKNOWNOID;
((TargetEntry *) lfirst(next_target))->resdom->restype = UNKNOWNOID;
}
#endif
}
else if (itype == InvalidOid)
{
}
/* they don't match in type? then convert... */
else if (itype != otype)
{
Node *expr;
expr = ((TargetEntry *) lfirst(next_target))->expr;
expr = CoerceTargetExpr(NULL, expr, itype, otype);
if (expr == NULL)
{
elog(ERROR, "Unable to transform %s to %s"
"\n\tEach UNION | EXCEPT | INTERSECT clause must have compatible target types",
typeidTypeName(itype),
typeidTypeName(otype));
}
((TargetEntry *) lfirst(next_target))->expr = expr;
((TargetEntry *) lfirst(next_target))->resdom->restype = otype;
}
/* both are UNKNOWN? then evaluate as text... */
else if (itype == UNKNOWNOID)
{
((TargetEntry *) lfirst(next_target))->resdom->restype = TEXTOID;
((TargetEntry *) lfirst(prev_target))->resdom->restype = TEXTOID;
}
prev_target = lnext(prev_target);
}
}
/***S*I***/
/* Rewrites UNION INTERSECT and EXCEPT queries to semantiacally equivalent
* queries that use IN and NOT IN subselects.
*
* The operator tree is attached to 'intersectClause' (see rule
* 'SelectStmt' in gram.y) of the 'parsetree' given as an
* argument. First we remember some clauses (the sortClause, the
* unique flag etc.) Then we translate the operator tree to DNF
* (disjunctive normal form) by 'cnfify'. (Note that 'cnfify' produces
* CNF but as we exchanged ANDs with ORs in function A_Expr_to_Expr()
* earlier we get DNF after exchanging ANDs and ORs again in the
* result.) Now we create a new query by evaluating the new operator
* tree which is in DNF now. For every AND we create an entry in the
* union list and for every OR we create an IN subselect. (NOT IN
* subselects are created for OR NOT nodes). The first entry of the
* union list is handed back but before that the remembered clauses
* (sortClause etc) are attached to the new top Node (Note that the
* new top Node can differ from the parsetree given as argument because of
* the translation to DNF. That's why we have to remember the sortClause or
* unique flag!) */
Query *
Except_Intersect_Rewrite (Query *parsetree)
{
SubLink *n;
Query *result, *intersect_node;
List *elist, *intersect_list = NIL, *intersect, *intersectClause;
List *union_list = NIL, *sortClause;
List *left_expr, *right_expr, *resnames = NIL;
char *op, *uniqueFlag, *into;
bool isBinary, isPortal, isTemp;
CmdType commandType = CMD_SELECT;
List *rtable_insert = NIL;
List *prev_target = NIL;
/* Remember the Resnames of the given parsetree's targetlist
* (these are the resnames of the first Select Statement of
* the query formulated by the user and he wants the columns
* named by these strings. The transformation to DNF can
* cause another Select Statment to be the top one which
* uses other names for its columns. Therefore we remeber
* the original names and attach them to the targetlist
* of the new topmost Node at the end of this function */
foreach(elist, parsetree->targetList)
{
TargetEntry *tent = (TargetEntry *)lfirst(elist);
resnames = lappend(resnames, tent->resdom->resname);
}
/* If the Statement is an INSERT INTO ... (SELECT...) statement
* using UNIONs, INTERSECTs or EXCEPTs and the transformation
* to DNF makes another Node to the top node we have to transform
* the new top node to an INSERT node and the original INSERT node
* to a SELECT node */
if (parsetree->commandType == CMD_INSERT)
{
parsetree->commandType = CMD_SELECT;
commandType = CMD_INSERT;
parsetree->resultRelation = 0;
/* The result relation ( = the one to insert into) has to be
* attached to the rtable list of the new top node */
rtable_insert = nth(length(parsetree->rtable) - 1, parsetree->rtable);
}
/* Save some items, to be able to attach them to the resulting top node
* at the end of the function */
sortClause = parsetree->sortClause;
uniqueFlag = parsetree->uniqueFlag;
into = parsetree->into;
isBinary = parsetree->isBinary;
isPortal = parsetree->isPortal;
isTemp = parsetree->isTemp;
/* The operator tree attached to parsetree->intersectClause is still 'raw'
* ( = the leaf nodes are still SelectStmt nodes instead of Query nodes)
* So step through the tree and transform the nodes using parse_analyze().
*
* The parsetree (given as an argument to
* Except_Intersect_Rewrite()) has already been transformed and
* transforming it again would cause troubles. So we give the 'raw'
* version (of the cooked parsetree) to the function to
* prevent an additional transformation. Instead we hand back the
* 'cooked' version also given as an argument to
* intersect_tree_analyze() */
intersectClause =
(List *)intersect_tree_analyze((Node *)parsetree->intersectClause,
(Node *)lfirst(parsetree->unionClause),
(Node *)parsetree);
/* intersectClause is no longer needed so set it to NIL */
parsetree->intersectClause = NIL;
/* unionClause will be needed later on but the list it delivered
* is no longer needed, so set it to NIL */
parsetree->unionClause = NIL;
/* Transform the operator tree to DNF (remember ANDs and ORs have been exchanged,
* that's why we get DNF by using cnfify)
*
* After the call, explicit ANDs are removed and all AND operands
* are simply items in the intersectClause list */
intersectClause = cnfify((Expr *)intersectClause, true);
/* For every entry of the intersectClause list we generate one entry in
* the union_list */
foreach(intersect, intersectClause)
{
/* for every OR we create an IN subselect and for every OR NOT
* we create a NOT IN subselect, so first extract all the Select
* Query nodes from the tree (that contains only OR or OR NOTs
* any more because we did a transformation to DNF
*
* There must be at least one node that is not negated
* (i.e. just OR and not OR NOT) and this node will be the first
* in the list returned */
intersect_list = NIL;
create_list((Node *)lfirst(intersect), &intersect_list);
/* This one will become the Select Query node, all other
* nodes are transformed into subselects under this node! */
intersect_node = (Query *)lfirst(intersect_list);
intersect_list = lnext(intersect_list);
/* Check if all Select Statements use the same number of attributes and
* if all corresponding attributes are of the same type */
if (prev_target)
check_targetlists_are_compatible(prev_target, intersect_node->targetList);
prev_target = intersect_node->targetList;
/* End of check for corresponding targetlists */
/* Transform all nodes remaining into subselects and add them to
* the qualifications of the Select Query node */
while(intersect_list != NIL) {
n = makeNode(SubLink);
/* Here we got an OR so transform it to an IN subselect */
if(IsA(lfirst(intersect_list), Query))
{
/* Check if all Select Statements use the same number of attributes and
* if all corresponding attributes are of the same type */
check_targetlists_are_compatible(prev_target,
((Query *)lfirst(intersect_list))->targetList);
/* End of check for corresponding targetlists */
n->subselect = lfirst(intersect_list);
op = "=";
n->subLinkType = ANY_SUBLINK;
n->useor = false;
}
/* Here we got an OR NOT node so transform it to a NOT IN subselect */
else
{
/* Check if all Select Statements use the same number of attributes and
* if all corresponding attributes are of the same type */
check_targetlists_are_compatible(prev_target,
((Query *)lfirst(((Expr *)lfirst(intersect_list))->args))->targetList);
/* End of check for corresponding targetlists */
n->subselect = (Node *)lfirst(((Expr *)lfirst(intersect_list))->args);
op = "<>";
n->subLinkType = ALL_SUBLINK;
n->useor = true;
}
/* Prepare the lefthand side of the Sublinks: All the entries of the
* targetlist must be (IN) or must not be (NOT IN) the subselect */
foreach(elist, intersect_node->targetList)
{
Node *expr = lfirst(elist);
TargetEntry *tent = (TargetEntry *)expr;
n->lefthand = lappend(n->lefthand, tent->expr);
}
/* The first arguments of oper also have to be created for the
* sublink (they are the same as the lefthand side!) */
left_expr = n->lefthand;
right_expr = ((Query *)(n->subselect))->targetList;
foreach(elist, left_expr)
{
Node *lexpr = lfirst(elist);
Node *rexpr = lfirst(right_expr);
TargetEntry *tent = (TargetEntry *) rexpr;
Expr *op_expr;
op_expr = make_op(op, lexpr, tent->expr);
n->oper = lappend(n->oper, op_expr);
right_expr = lnext(right_expr);
}
/* If the Select Query node has aggregates in use
* add all the subselects to the HAVING qual else to
* the WHERE qual */
if(intersect_node->hasAggs == false) {
AddQual(intersect_node, (Node *)n);
}
else {
AddHavingQual(intersect_node, (Node *)n);
}
/* Now we got sublinks */
intersect_node->hasSubLinks = true;
intersect_list = lnext(intersect_list);
}
intersect_node->intersectClause = NIL;
union_list = lappend(union_list, intersect_node);
}
/* The first entry to union_list is our new top node */
result = (Query *)lfirst(union_list);
/* attach the rest to unionClause */
result->unionClause = lnext(union_list);
/* Attach all the items remembered in the beginning of the function */
result->sortClause = sortClause;
result->uniqueFlag = uniqueFlag;
result->into = into;
result->isPortal = isPortal;
result->isBinary = isBinary;
result->isTemp = isTemp;
/* The relation to insert into is attached to the range table
* of the new top node */
if (commandType == CMD_INSERT)
{
result->rtable = lappend(result->rtable, rtable_insert);
result->resultRelation = length(result->rtable);
result->commandType = commandType;
}
/* The resnames of the originally first SelectStatement are
* attached to the new first SelectStatement */
foreach(elist, result->targetList)
{
TargetEntry *tent = (TargetEntry *)lfirst(elist);
tent->resdom->resname = lfirst(resnames);
resnames = lnext(resnames);
}
return result;
}
/* Create a list of nodes that are either Query nodes of NOT Expr
* nodes followed by a Query node. The tree given in ptr contains at
* least one non negated Query node. This node is attached to the
* beginning of the list */
void create_list(Node *ptr, List **intersect_list)
{
List *arg;
if(IsA(ptr,Query))
{
/* The non negated node is attached at the beginning (lcons) */
*intersect_list = lcons(ptr, *intersect_list);
return;
}
if(IsA(ptr,Expr))
{
if(((Expr *)ptr)->opType == NOT_EXPR)
{
/* negated nodes are appended to the end (lappend) */
*intersect_list = lappend(*intersect_list, ptr);
return;
}
else
{
foreach(arg, ((Expr *)ptr)->args)
{
create_list(lfirst(arg), intersect_list);
}
return;
}
return;
}
}
/* The nodes given in 'tree' are still 'raw' so 'cook' them using parse_analyze().
* The node given in first_select has already been cooked, so don't transform
* it again but return a pointer to the previously cooked version given in 'parsetree'
* instead. */
Node *intersect_tree_analyze(Node *tree, Node *first_select, Node *parsetree)
{
Node *result = (Node *) NIL;
List *arg;
if (IsA(tree, SelectStmt))
{
/* If we get to the tree given in first_select return
* parsetree instead of performing parse_analyze() */
if (tree == first_select)
{
result = parsetree;
}
else
{
/* transform the 'raw' nodes to 'cooked' Query nodes */
List *qtree = parse_analyze(lcons(tree, NIL), NULL);
result = (Node *) lfirst(qtree);
}
}
if(IsA(tree,Expr))
{
/* Call recursively for every argument of the node */
foreach(arg, ((Expr *)tree)->args)
{
lfirst(arg) = intersect_tree_analyze(lfirst(arg), first_select, parsetree);
}
result = tree;
}
return result;
}
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