mirror of
https://git.postgresql.org/git/postgresql.git
synced 2024-08-20 04:33:23 +02:00
f68e11f373
subselects can only appear on the righthand side of a binary operator. That's still true for quantified predicates like x = ANY (SELECT ...), but a subselect that delivers a single result can now appear anywhere in an expression. This is implemented by changing EXPR_SUBLINK sublinks to represent just the (SELECT ...) expression, without any 'left hand side' or combining operator --- so they're now more like EXISTS_SUBLINK. To handle the case of '(x, y, z) = (SELECT ...)', I added a new sublink type MULTIEXPR_SUBLINK, which acts just like EXPR_SUBLINK used to. But the grammar will only generate one for a multiple-left-hand-side row expression.
2117 lines
55 KiB
C
2117 lines
55 KiB
C
/*-------------------------------------------------------------------------
|
|
*
|
|
* rewriteHandler.c
|
|
*
|
|
* Copyright (c) 1994, Regents of the University of California
|
|
*
|
|
*
|
|
* IDENTIFICATION
|
|
* $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteHandler.c,v 1.63 1999/11/15 02:00:03 tgl Exp $
|
|
*
|
|
*-------------------------------------------------------------------------
|
|
*/
|
|
#include "postgres.h"
|
|
|
|
#include "access/heapam.h"
|
|
#include "catalog/pg_operator.h"
|
|
#include "catalog/pg_type.h"
|
|
#include "miscadmin.h"
|
|
#include "nodes/makefuncs.h"
|
|
#include "optimizer/clauses.h"
|
|
#include "optimizer/prep.h"
|
|
#include "parser/analyze.h"
|
|
#include "parser/parse_expr.h"
|
|
#include "parser/parse_relation.h"
|
|
#include "parser/parse_oper.h"
|
|
#include "parser/parse_target.h"
|
|
#include "parser/parse_type.h"
|
|
#include "parser/parsetree.h"
|
|
#include "rewrite/locks.h"
|
|
#include "rewrite/rewriteManip.h"
|
|
#include "utils/acl.h"
|
|
#include "utils/lsyscache.h"
|
|
|
|
|
|
extern void CheckSelectForUpdate(Query *rule_action); /* in analyze.c */
|
|
|
|
|
|
/* macros borrowed from expression_tree_mutator */
|
|
|
|
#define FLATCOPY(newnode, node, nodetype) \
|
|
( (newnode) = makeNode(nodetype), \
|
|
memcpy((newnode), (node), sizeof(nodetype)) )
|
|
|
|
#define MUTATE(newfield, oldfield, fieldtype, mutator, context) \
|
|
( (newfield) = (fieldtype) mutator((Node *) (oldfield), (context)) )
|
|
|
|
|
|
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 bool modifyAggrefUplevel(Node *node, void *context);
|
|
static bool modifyAggrefChangeVarnodes(Node *node, int rt_index, int new_index,
|
|
int sublevels_up, int new_sublevels_up);
|
|
static Node *modifyAggrefDropQual(Node *node, Node *targetNode);
|
|
static SubLink *modifyAggrefMakeSublink(Aggref *aggref, Query *parsetree);
|
|
static Node *modifyAggrefQual(Node *node, Query *parsetree);
|
|
static bool checkQueryHasAggs(Node *node);
|
|
static bool checkQueryHasAggs_walker(Node *node, void *context);
|
|
static bool checkQueryHasSubLink(Node *node);
|
|
static bool checkQueryHasSubLink_walker(Node *node, void *context);
|
|
static Query *fireRIRrules(Query *parsetree);
|
|
static Query *Except_Intersect_Rewrite(Query *parsetree);
|
|
static void check_targetlists_are_compatible(List *prev_target,
|
|
List *current_target);
|
|
static void create_intersect_list(Node *ptr, List **intersect_list);
|
|
static Node *intersect_tree_analyze(Node *tree, Node *first_select,
|
|
Node *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.
|
|
*/
|
|
|
|
typedef struct {
|
|
int rt_index;
|
|
int sublevels_up;
|
|
} rangeTableEntry_used_context;
|
|
|
|
static bool
|
|
rangeTableEntry_used_walker (Node *node,
|
|
rangeTableEntry_used_context *context)
|
|
{
|
|
if (node == NULL)
|
|
return false;
|
|
if (IsA(node, Var))
|
|
{
|
|
Var *var = (Var *) node;
|
|
|
|
if (var->varlevelsup == context->sublevels_up &&
|
|
var->varno == context->rt_index)
|
|
return true;
|
|
return false;
|
|
}
|
|
if (IsA(node, SubLink))
|
|
{
|
|
/*
|
|
* Standard expression_tree_walker will not recurse into subselect,
|
|
* but here we must do so.
|
|
*/
|
|
SubLink *sub = (SubLink *) node;
|
|
|
|
if (rangeTableEntry_used_walker((Node *) (sub->lefthand), context))
|
|
return true;
|
|
if (rangeTableEntry_used((Node *) (sub->subselect),
|
|
context->rt_index,
|
|
context->sublevels_up + 1))
|
|
return true;
|
|
return false;
|
|
}
|
|
if (IsA(node, Query))
|
|
{
|
|
/* Reach here after recursing down into subselect above... */
|
|
Query *qry = (Query *) node;
|
|
|
|
if (rangeTableEntry_used_walker((Node *) (qry->targetList), context))
|
|
return true;
|
|
if (rangeTableEntry_used_walker((Node *) (qry->qual), context))
|
|
return true;
|
|
if (rangeTableEntry_used_walker((Node *) (qry->havingQual), context))
|
|
return true;
|
|
return false;
|
|
}
|
|
return expression_tree_walker(node, rangeTableEntry_used_walker,
|
|
(void *) context);
|
|
}
|
|
|
|
static bool
|
|
rangeTableEntry_used(Node *node, int rt_index, int sublevels_up)
|
|
{
|
|
rangeTableEntry_used_context context;
|
|
|
|
context.rt_index = rt_index;
|
|
context.sublevels_up = sublevels_up;
|
|
return rangeTableEntry_used_walker(node, &context);
|
|
}
|
|
|
|
|
|
/*
|
|
* attribute_used -
|
|
* Check if a specific attribute number of a RTE is used
|
|
* somewhere in the query
|
|
*/
|
|
|
|
typedef struct {
|
|
int rt_index;
|
|
int attno;
|
|
int sublevels_up;
|
|
} attribute_used_context;
|
|
|
|
static bool
|
|
attribute_used_walker (Node *node,
|
|
attribute_used_context *context)
|
|
{
|
|
if (node == NULL)
|
|
return false;
|
|
if (IsA(node, Var))
|
|
{
|
|
Var *var = (Var *) node;
|
|
|
|
if (var->varlevelsup == context->sublevels_up &&
|
|
var->varno == context->rt_index &&
|
|
var->varattno == context->attno)
|
|
return true;
|
|
return false;
|
|
}
|
|
if (IsA(node, SubLink))
|
|
{
|
|
/*
|
|
* Standard expression_tree_walker will not recurse into subselect,
|
|
* but here we must do so.
|
|
*/
|
|
SubLink *sub = (SubLink *) node;
|
|
|
|
if (attribute_used_walker((Node *) (sub->lefthand), context))
|
|
return true;
|
|
if (attribute_used((Node *) (sub->subselect),
|
|
context->rt_index,
|
|
context->attno,
|
|
context->sublevels_up + 1))
|
|
return true;
|
|
return false;
|
|
}
|
|
if (IsA(node, Query))
|
|
{
|
|
/* Reach here after recursing down into subselect above... */
|
|
Query *qry = (Query *) node;
|
|
|
|
if (attribute_used_walker((Node *) (qry->targetList), context))
|
|
return true;
|
|
if (attribute_used_walker((Node *) (qry->qual), context))
|
|
return true;
|
|
if (attribute_used_walker((Node *) (qry->havingQual), context))
|
|
return true;
|
|
return false;
|
|
}
|
|
return expression_tree_walker(node, attribute_used_walker,
|
|
(void *) context);
|
|
}
|
|
|
|
static bool
|
|
attribute_used(Node *node, int rt_index, int attno, int sublevels_up)
|
|
{
|
|
attribute_used_context context;
|
|
|
|
context.rt_index = rt_index;
|
|
context.attno = attno;
|
|
context.sublevels_up = sublevels_up;
|
|
return attribute_used_walker(node, &context);
|
|
}
|
|
|
|
|
|
/*
|
|
* modifyAggrefUplevel -
|
|
* In the newly created sublink for an aggregate column used in
|
|
* the qualification, we must increment the varlevelsup in all the
|
|
* var nodes.
|
|
*
|
|
* NOTE: although this has the form of a walker, we cheat and modify the
|
|
* Var nodes in-place. The given expression tree should have been copied
|
|
* earlier to ensure that no unwanted side-effects occur!
|
|
*/
|
|
static bool
|
|
modifyAggrefUplevel(Node *node, void *context)
|
|
{
|
|
if (node == NULL)
|
|
return false;
|
|
if (IsA(node, Var))
|
|
{
|
|
Var *var = (Var *) node;
|
|
|
|
var->varlevelsup++;
|
|
return false;
|
|
}
|
|
if (IsA(node, SubLink))
|
|
{
|
|
/*
|
|
* Standard expression_tree_walker will not recurse into subselect,
|
|
* but here we must do so.
|
|
*/
|
|
SubLink *sub = (SubLink *) node;
|
|
|
|
if (modifyAggrefUplevel((Node *) (sub->lefthand), context))
|
|
return true;
|
|
if (modifyAggrefUplevel((Node *) (sub->subselect), context))
|
|
return true;
|
|
return false;
|
|
}
|
|
if (IsA(node, Query))
|
|
{
|
|
/* Reach here after recursing down into subselect above... */
|
|
Query *qry = (Query *) node;
|
|
|
|
if (modifyAggrefUplevel((Node *) (qry->targetList), context))
|
|
return true;
|
|
if (modifyAggrefUplevel((Node *) (qry->qual), context))
|
|
return true;
|
|
if (modifyAggrefUplevel((Node *) (qry->havingQual), context))
|
|
return true;
|
|
return false;
|
|
}
|
|
return expression_tree_walker(node, modifyAggrefUplevel,
|
|
(void *) context);
|
|
}
|
|
|
|
|
|
/*
|
|
* modifyAggrefChangeVarnodes -
|
|
* Change the var nodes in a sublink created for an aggregate column
|
|
* used in the qualification to point to the correct local RTE.
|
|
*
|
|
* NOTE: although this has the form of a walker, we cheat and modify the
|
|
* Var nodes in-place. The given expression tree should have been copied
|
|
* earlier to ensure that no unwanted side-effects occur!
|
|
*/
|
|
|
|
typedef struct {
|
|
int rt_index;
|
|
int new_index;
|
|
int sublevels_up;
|
|
int new_sublevels_up;
|
|
} modifyAggrefChangeVarnodes_context;
|
|
|
|
static bool
|
|
modifyAggrefChangeVarnodes_walker(Node *node,
|
|
modifyAggrefChangeVarnodes_context *context)
|
|
{
|
|
if (node == NULL)
|
|
return false;
|
|
if (IsA(node, Var))
|
|
{
|
|
Var *var = (Var *) node;
|
|
|
|
if (var->varlevelsup == context->sublevels_up &&
|
|
var->varno == context->rt_index)
|
|
{
|
|
var->varno = context->new_index;
|
|
var->varnoold = context->new_index;
|
|
var->varlevelsup = context->new_sublevels_up;
|
|
}
|
|
return false;
|
|
}
|
|
if (IsA(node, SubLink))
|
|
{
|
|
/*
|
|
* Standard expression_tree_walker will not recurse into subselect,
|
|
* but here we must do so.
|
|
*/
|
|
SubLink *sub = (SubLink *) node;
|
|
|
|
if (modifyAggrefChangeVarnodes_walker((Node *) (sub->lefthand),
|
|
context))
|
|
return true;
|
|
if (modifyAggrefChangeVarnodes((Node *) (sub->subselect),
|
|
context->rt_index,
|
|
context->new_index,
|
|
context->sublevels_up + 1,
|
|
context->new_sublevels_up + 1))
|
|
return true;
|
|
return false;
|
|
}
|
|
if (IsA(node, Query))
|
|
{
|
|
/* Reach here after recursing down into subselect above... */
|
|
Query *qry = (Query *) node;
|
|
|
|
if (modifyAggrefChangeVarnodes_walker((Node *) (qry->targetList),
|
|
context))
|
|
return true;
|
|
if (modifyAggrefChangeVarnodes_walker((Node *) (qry->qual),
|
|
context))
|
|
return true;
|
|
if (modifyAggrefChangeVarnodes_walker((Node *) (qry->havingQual),
|
|
context))
|
|
return true;
|
|
return false;
|
|
}
|
|
return expression_tree_walker(node, modifyAggrefChangeVarnodes_walker,
|
|
(void *) context);
|
|
}
|
|
|
|
static bool
|
|
modifyAggrefChangeVarnodes(Node *node, int rt_index, int new_index,
|
|
int sublevels_up, int new_sublevels_up)
|
|
{
|
|
modifyAggrefChangeVarnodes_context context;
|
|
|
|
context.rt_index = rt_index;
|
|
context.new_index = new_index;
|
|
context.sublevels_up = sublevels_up;
|
|
context.new_sublevels_up = new_sublevels_up;
|
|
return modifyAggrefChangeVarnodes_walker(node, &context);
|
|
}
|
|
|
|
|
|
/*
|
|
* modifyAggrefDropQual -
|
|
* remove the pure aggref clause from a qualification
|
|
*
|
|
* targetNode is an Aggref node somewhere within the given expression tree.
|
|
* Find the boolean operator that's presumably somewhere above it, and replace
|
|
* that whole operator expression with a constant TRUE. (This is NOT really
|
|
* quite the right thing, but it handles simple cases. This whole set of
|
|
* Aggref-in-qual routines needs to be thrown away when we can do subselects
|
|
* in FROM.)
|
|
*
|
|
* The return tree is a modified copy of the given tree; the given tree
|
|
* is not altered.
|
|
*
|
|
* Note: we don't recurse into subselects looking for targetNode; that's
|
|
* not necessary in the current usage, since in fact targetNode will be
|
|
* within the same select level as the given toplevel node.
|
|
*/
|
|
static Node *
|
|
modifyAggrefDropQual(Node *node, Node *targetNode)
|
|
{
|
|
if (node == NULL)
|
|
return NULL;
|
|
if (node == targetNode)
|
|
{
|
|
/* Oops, it's not inside an Expr we can rearrange... */
|
|
elog(ERROR, "Cannot handle aggregate function inserted at this place in WHERE clause");
|
|
}
|
|
if (IsA(node, Expr))
|
|
{
|
|
Expr *expr = (Expr *) node;
|
|
List *i;
|
|
|
|
foreach(i, expr->args)
|
|
{
|
|
if (((Node *) lfirst(i)) == targetNode)
|
|
{
|
|
/* Found the parent expression containing the Aggref */
|
|
if (expr->typeOid != BOOLOID)
|
|
elog(ERROR,
|
|
"aggregate function in qual must be argument of boolean operator");
|
|
return (Node *) makeConst(BOOLOID, 1, (Datum) true,
|
|
false, true, false, false);
|
|
}
|
|
}
|
|
/* else this isn't the expr we want, keep going */
|
|
}
|
|
return expression_tree_mutator(node, modifyAggrefDropQual,
|
|
(void *) targetNode);
|
|
}
|
|
|
|
/*
|
|
* modifyAggrefMakeSublink -
|
|
* Create a sublink node for a qualification expression that
|
|
* uses an aggregate column of a view
|
|
*/
|
|
static SubLink *
|
|
modifyAggrefMakeSublink(Aggref *aggref, Query *parsetree)
|
|
{
|
|
/* target and rte point to old structures: */
|
|
Var *target;
|
|
RangeTblEntry *rte;
|
|
/* these point to newly-created structures: */
|
|
Query *subquery;
|
|
SubLink *sublink;
|
|
TargetEntry *tle;
|
|
Resdom *resdom;
|
|
|
|
target = (Var *) (aggref->target);
|
|
if (! IsA(target, Var))
|
|
elog(ERROR, "rewrite: aggregates of views only allowed on simple variables for now");
|
|
rte = rt_fetch(target->varno, parsetree->rtable);
|
|
|
|
resdom = makeNode(Resdom);
|
|
resdom->resno = 1;
|
|
resdom->restype = aggref->aggtype;
|
|
resdom->restypmod = -1;
|
|
resdom->resname = pstrdup("<noname>");
|
|
resdom->reskey = 0;
|
|
resdom->reskeyop = 0;
|
|
resdom->resjunk = false;
|
|
|
|
tle = makeNode(TargetEntry);
|
|
tle->resdom = resdom;
|
|
tle->expr = copyObject(aggref); /* make a modifiable copy! */
|
|
|
|
subquery = makeNode(Query);
|
|
|
|
sublink = makeNode(SubLink);
|
|
sublink->subLinkType = EXPR_SUBLINK;
|
|
sublink->useor = false;
|
|
sublink->lefthand = NIL;
|
|
sublink->oper = NIL;
|
|
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 = lcons(copyObject(rte), NIL);
|
|
subquery->targetList = lcons(tle, NIL);
|
|
subquery->qual = modifyAggrefDropQual((Node *) parsetree->qual,
|
|
(Node *) aggref);
|
|
/*
|
|
* If there are still aggs in the subselect's qual, give up.
|
|
* Recursing would be a bad idea --- we'd likely produce an
|
|
* infinite recursion. This whole technique is a crock, really...
|
|
*/
|
|
if (checkQueryHasAggs(subquery->qual))
|
|
elog(ERROR, "Cannot handle multiple aggregate functions in WHERE clause");
|
|
subquery->groupClause = NIL;
|
|
subquery->havingQual = NULL;
|
|
subquery->hasAggs = TRUE;
|
|
subquery->hasSubLinks = checkQueryHasSubLink(subquery->qual);
|
|
subquery->unionClause = NULL;
|
|
|
|
/* Increment all varlevelsup fields in the new subquery */
|
|
modifyAggrefUplevel((Node *) subquery, NULL);
|
|
|
|
/* Replace references to the target table with correct varno.
|
|
* Note +1 here to account for effects of previous line!
|
|
*/
|
|
modifyAggrefChangeVarnodes((Node *) subquery, target->varno,
|
|
1, target->varlevelsup+1, 0);
|
|
|
|
return sublink;
|
|
}
|
|
|
|
|
|
/*
|
|
* modifyAggrefQual -
|
|
* Search for qualification expressions that contain aggregate
|
|
* functions and substitute them by sublinks. These expressions
|
|
* originally come from qualifications that use aggregate columns
|
|
* of a view.
|
|
*
|
|
* The return value is a modified copy of the given expression tree.
|
|
*/
|
|
static Node *
|
|
modifyAggrefQual(Node *node, Query *parsetree)
|
|
{
|
|
if (node == NULL)
|
|
return NULL;
|
|
if (IsA(node, Aggref))
|
|
{
|
|
SubLink *sub = modifyAggrefMakeSublink((Aggref *) node, parsetree);
|
|
|
|
parsetree->hasSubLinks = true;
|
|
return (Node *) sub;
|
|
}
|
|
/*
|
|
* Otherwise, fall through and copy the expr normally.
|
|
*
|
|
* We do NOT recurse into subselects in this routine. It's sufficient
|
|
* to get rid of aggregates that are in the qual expression proper.
|
|
*/
|
|
return expression_tree_mutator(node, modifyAggrefQual,
|
|
(void *) parsetree);
|
|
}
|
|
|
|
|
|
/*
|
|
* checkQueryHasAggs -
|
|
* Queries marked hasAggs might not have them any longer after
|
|
* rewriting. Check it.
|
|
*/
|
|
static bool
|
|
checkQueryHasAggs(Node *node)
|
|
{
|
|
return checkQueryHasAggs_walker(node, NULL);
|
|
}
|
|
|
|
static bool
|
|
checkQueryHasAggs_walker(Node *node, void *context)
|
|
{
|
|
if (node == NULL)
|
|
return false;
|
|
if (IsA(node, Aggref))
|
|
return true; /* abort the tree traversal and return true */
|
|
return expression_tree_walker(node, checkQueryHasAggs_walker, context);
|
|
}
|
|
|
|
/*
|
|
* checkQueryHasSubLink -
|
|
* Queries marked hasSubLinks might not have them any longer after
|
|
* rewriting. Check it.
|
|
*/
|
|
static bool
|
|
checkQueryHasSubLink(Node *node)
|
|
{
|
|
return checkQueryHasSubLink_walker(node, NULL);
|
|
}
|
|
|
|
static bool
|
|
checkQueryHasSubLink_walker(Node *node, void *context)
|
|
{
|
|
if (node == NULL)
|
|
return false;
|
|
if (IsA(node, SubLink))
|
|
return true; /* abort the tree traversal and return true */
|
|
return expression_tree_walker(node, checkQueryHasSubLink_walker, context);
|
|
}
|
|
|
|
|
|
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;
|
|
}
|
|
|
|
|
|
/*
|
|
* apply_RIR_adjust_sublevel -
|
|
* Set the varlevelsup field of all Var nodes in the given expression tree
|
|
* to sublevels_up. We do NOT recurse into subselects.
|
|
*
|
|
* NOTE: although this has the form of a walker, we cheat and modify the
|
|
* Var nodes in-place. The given expression tree should have been copied
|
|
* earlier to ensure that no unwanted side-effects occur!
|
|
*/
|
|
static bool
|
|
apply_RIR_adjust_sublevel_walker(Node *node, int *sublevels_up)
|
|
{
|
|
if (node == NULL)
|
|
return false;
|
|
if (IsA(node, Var))
|
|
{
|
|
Var *var = (Var *) node;
|
|
|
|
var->varlevelsup = *sublevels_up;
|
|
return false;
|
|
}
|
|
return expression_tree_walker(node, apply_RIR_adjust_sublevel_walker,
|
|
(void *) sublevels_up);
|
|
}
|
|
|
|
static void
|
|
apply_RIR_adjust_sublevel(Node *node, int sublevels_up)
|
|
{
|
|
apply_RIR_adjust_sublevel_walker(node, &sublevels_up);
|
|
}
|
|
|
|
|
|
/*
|
|
* apply_RIR_view
|
|
* Replace Vars matching a given RT index with copies of TL expressions.
|
|
*/
|
|
|
|
typedef struct {
|
|
int rt_index;
|
|
int sublevels_up;
|
|
RangeTblEntry *rte;
|
|
List *tlist;
|
|
int *modified;
|
|
} apply_RIR_view_context;
|
|
|
|
static Node *
|
|
apply_RIR_view_mutator(Node *node,
|
|
apply_RIR_view_context *context)
|
|
{
|
|
if (node == NULL)
|
|
return NULL;
|
|
if (IsA(node, Var))
|
|
{
|
|
Var *var = (Var *) node;
|
|
|
|
if (var->varlevelsup == context->sublevels_up &&
|
|
var->varno == context->rt_index)
|
|
{
|
|
Node *expr;
|
|
|
|
if (var->varattno < 0)
|
|
elog(ERROR, "system column %s not available - %s is a view",
|
|
get_attname(context->rte->relid, var->varattno),
|
|
context->rte->relname);
|
|
|
|
expr = FindMatchingTLEntry(context->tlist,
|
|
get_attname(context->rte->relid,
|
|
var->varattno));
|
|
if (expr == NULL)
|
|
{
|
|
/* XXX shouldn't this be an error condition? */
|
|
return make_null(var->vartype);
|
|
}
|
|
|
|
expr = copyObject(expr);
|
|
if (var->varlevelsup > 0)
|
|
apply_RIR_adjust_sublevel(expr, var->varlevelsup);
|
|
*(context->modified) = true;
|
|
return (Node *) expr;
|
|
}
|
|
/* otherwise fall through to copy the var normally */
|
|
}
|
|
/*
|
|
* Since expression_tree_mutator won't touch subselects, we have to
|
|
* handle them specially.
|
|
*/
|
|
if (IsA(node, SubLink))
|
|
{
|
|
SubLink *sublink = (SubLink *) node;
|
|
SubLink *newnode;
|
|
|
|
FLATCOPY(newnode, sublink, SubLink);
|
|
MUTATE(newnode->lefthand, sublink->lefthand, List *,
|
|
apply_RIR_view_mutator, context);
|
|
context->sublevels_up++;
|
|
MUTATE(newnode->subselect, sublink->subselect, Node *,
|
|
apply_RIR_view_mutator, context);
|
|
context->sublevels_up--;
|
|
return (Node *) newnode;
|
|
}
|
|
if (IsA(node, Query))
|
|
{
|
|
Query *query = (Query *) node;
|
|
Query *newnode;
|
|
|
|
FLATCOPY(newnode, query, Query);
|
|
MUTATE(newnode->targetList, query->targetList, List *,
|
|
apply_RIR_view_mutator, context);
|
|
MUTATE(newnode->qual, query->qual, Node *,
|
|
apply_RIR_view_mutator, context);
|
|
MUTATE(newnode->havingQual, query->havingQual, Node *,
|
|
apply_RIR_view_mutator, context);
|
|
return (Node *) newnode;
|
|
}
|
|
return expression_tree_mutator(node, apply_RIR_view_mutator,
|
|
(void *) context);
|
|
}
|
|
|
|
static Node *
|
|
apply_RIR_view(Node *node, int rt_index, RangeTblEntry *rte, List *tlist,
|
|
int *modified, int sublevels_up)
|
|
{
|
|
apply_RIR_view_context context;
|
|
|
|
context.rt_index = rt_index;
|
|
context.sublevels_up = sublevels_up;
|
|
context.rte = rte;
|
|
context.tlist = tlist;
|
|
context.modified = modified;
|
|
|
|
return apply_RIR_view_mutator(node, &context);
|
|
}
|
|
|
|
|
|
static Query *
|
|
ApplyRetrieveRule(Query *parsetree,
|
|
RewriteRule *rule,
|
|
int rt_index,
|
|
int relation_level,
|
|
Relation relation,
|
|
bool relWasInJoinSet,
|
|
int *modified)
|
|
{
|
|
Query *rule_action = NULL;
|
|
Node *rule_qual;
|
|
List *rtable,
|
|
*addedrtable,
|
|
*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 parsetree;
|
|
rule_action = copyObject(lfirst(rule->actions));
|
|
nothing = FALSE;
|
|
}
|
|
else
|
|
nothing = TRUE;
|
|
|
|
rtable = copyObject(parsetree->rtable);
|
|
rt_length = length(rtable); /* original length, not counting rule */
|
|
|
|
addedrtable = copyObject(rule_action->rtable);
|
|
|
|
/* If the original rel wasn't in the join set, none of its spawn is.
|
|
* If it was, then leave the spawn's flags as they are.
|
|
*/
|
|
if (! relWasInJoinSet)
|
|
{
|
|
foreach(l, addedrtable)
|
|
{
|
|
RangeTblEntry *rte = lfirst(l);
|
|
rte->inJoinSet = false;
|
|
}
|
|
}
|
|
|
|
rtable = nconc(rtable, addedrtable);
|
|
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)
|
|
{
|
|
RangeTblEntry *rte = rt_fetch(rt_index, rtable);
|
|
|
|
parsetree = (Query *) apply_RIR_view((Node *) parsetree,
|
|
rt_index, rte,
|
|
rule_action->targetList,
|
|
modified, 0);
|
|
rule_action = (Query *) apply_RIR_view((Node *) rule_action,
|
|
rt_index, rte,
|
|
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);
|
|
}
|
|
|
|
return parsetree;
|
|
}
|
|
|
|
|
|
/*
|
|
* fireRIRonSubselect -
|
|
* Apply fireRIRrules() to each subselect found in the given tree.
|
|
*
|
|
* NOTE: although this has the form of a walker, we cheat and modify the
|
|
* SubLink nodes in-place. It is caller's responsibility to ensure that
|
|
* no unwanted side-effects occur!
|
|
*/
|
|
static bool
|
|
fireRIRonSubselect(Node *node, void *context)
|
|
{
|
|
if (node == NULL)
|
|
return false;
|
|
if (IsA(node, SubLink))
|
|
{
|
|
/*
|
|
* Standard expression_tree_walker will not recurse into subselect,
|
|
* but here we must do so.
|
|
*/
|
|
SubLink *sub = (SubLink *) node;
|
|
Query *qry;
|
|
|
|
/* Process lefthand args */
|
|
if (fireRIRonSubselect((Node *) (sub->lefthand), context))
|
|
return true;
|
|
/* Do what we came for */
|
|
qry = fireRIRrules((Query *) (sub->subselect));
|
|
sub->subselect = (Node *) qry;
|
|
/* Must recurse to handle any sub-subselects! */
|
|
if (fireRIRonSubselect((Node *) qry, context))
|
|
return true;
|
|
return false;
|
|
}
|
|
if (IsA(node, Query))
|
|
{
|
|
/* Reach here after recursing down into subselect above... */
|
|
Query *qry = (Query *) node;
|
|
|
|
if (fireRIRonSubselect((Node *) (qry->targetList), context))
|
|
return true;
|
|
if (fireRIRonSubselect((Node *) (qry->qual), context))
|
|
return true;
|
|
if (fireRIRonSubselect((Node *) (qry->havingQual), context))
|
|
return true;
|
|
return false;
|
|
}
|
|
return expression_tree_walker(node, fireRIRonSubselect,
|
|
(void *) context);
|
|
}
|
|
|
|
|
|
/*
|
|
* 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;
|
|
bool relWasInJoinSet;
|
|
int modified = false;
|
|
int i;
|
|
List *l;
|
|
|
|
/* don't try to convert this into a foreach loop, because
|
|
* rtable list can get changed each time through...
|
|
*/
|
|
rt_index = 0;
|
|
while (rt_index < length(parsetree->rtable))
|
|
{
|
|
++rt_index;
|
|
|
|
rte = rt_fetch(rt_index, parsetree->rtable);
|
|
|
|
/*
|
|
* If the table is not one named in the original FROM clause
|
|
* then it must be referenced in the query, or we ignore it.
|
|
* This prevents infinite expansion loop due to new rtable
|
|
* entries inserted by expansion of a rule.
|
|
*/
|
|
if (! rte->inFromCl && rt_index != parsetree->resultRelation &&
|
|
! rangeTableEntry_used((Node *) parsetree, rt_index, 0))
|
|
{
|
|
/* Make sure the planner ignores it too... */
|
|
rte->inJoinSet = false;
|
|
continue;
|
|
}
|
|
|
|
rel = heap_openr(rte->relname, AccessShareLock);
|
|
rules = rel->rd_rules;
|
|
if (rules == NULL)
|
|
{
|
|
heap_close(rel, AccessShareLock);
|
|
continue;
|
|
}
|
|
|
|
relWasInJoinSet = rte->inJoinSet; /* save before possibly clearing */
|
|
|
|
/*
|
|
* Collect the RIR rules that we must apply
|
|
*/
|
|
locks = NIL;
|
|
for (i = 0; i < rules->numLocks; i++)
|
|
{
|
|
rule = rules->rules[i];
|
|
if (rule->event != CMD_SELECT)
|
|
continue;
|
|
|
|
if (rule->attrno > 0)
|
|
{
|
|
/* per-attr rule; do we need it? */
|
|
if (! attribute_used((Node *) parsetree,
|
|
rt_index,
|
|
rule->attrno, 0))
|
|
continue;
|
|
}
|
|
else
|
|
{
|
|
/* Rel-wide ON SELECT DO INSTEAD means this is a view.
|
|
* Remove the view from the planner's join target set,
|
|
* or we'll get no rows out because view itself is empty!
|
|
*/
|
|
if (rule->isInstead)
|
|
rte->inJoinSet = false;
|
|
}
|
|
|
|
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;
|
|
|
|
parsetree = ApplyRetrieveRule(parsetree,
|
|
&RIRonly,
|
|
rt_index,
|
|
RIRonly.attrno == -1,
|
|
rel,
|
|
relWasInJoinSet,
|
|
&modified);
|
|
}
|
|
|
|
heap_close(rel, AccessShareLock);
|
|
}
|
|
|
|
if (parsetree->hasSubLinks)
|
|
fireRIRonSubselect((Node *) parsetree, NULL);
|
|
|
|
if (parsetree->hasAggs)
|
|
parsetree->qual = modifyAggrefQual(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 = rt_fetch(parsetree->resultRelation, 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;
|
|
|
|
/*
|
|
* the statement is an update, insert or delete - fire rules on it.
|
|
*/
|
|
result_relation = parsetree->resultRelation;
|
|
rt_entry = rt_fetch(result_relation, parsetree->rtable);
|
|
rt_entry_relation = heap_openr(rt_entry->relname, AccessShareLock);
|
|
rt_entry_locks = rt_entry_relation->rd_rules;
|
|
heap_close(rt_entry_relation, AccessShareLock);
|
|
|
|
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);
|
|
}
|
|
|
|
|
|
/*
|
|
* 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
|
|
*
|
|
* Apply all non-SELECT rules possibly getting 0 or many queries
|
|
*/
|
|
querylist = QueryRewriteOne(parsetree);
|
|
|
|
/*
|
|
* Step 2
|
|
*
|
|
* 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. Ditto for sublinks. Note there
|
|
* should be no aggs in the qual at this point.
|
|
*/
|
|
if (query->hasAggs)
|
|
{
|
|
query->hasAggs =
|
|
checkQueryHasAggs((Node *) (query->targetList)) ||
|
|
checkQueryHasAggs((Node *) (query->havingQual));
|
|
if (checkQueryHasAggs((Node *) (query->qual)))
|
|
elog(ERROR, "BasicQueryRewrite: failed to remove aggs from qual");
|
|
}
|
|
if (query->hasSubLinks)
|
|
query->hasSubLinks =
|
|
checkQueryHasSubLink((Node *) (query->targetList)) ||
|
|
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;
|
|
|
|
/*
|
|
* 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;
|
|
}
|
|
|
|
/* 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 */
|
|
static 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);
|
|
}
|
|
}
|
|
|
|
/* 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!) */
|
|
static 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;
|
|
Node *limitOffset,
|
|
*limitCount;
|
|
CmdType commandType = CMD_SELECT;
|
|
RangeTblEntry *rtable_insert = NULL;
|
|
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)
|
|
{
|
|
/*
|
|
* The result relation ( = the one to insert into) has to be
|
|
* attached to the rtable list of the new top node
|
|
*/
|
|
rtable_insert = rt_fetch(parsetree->resultRelation, parsetree->rtable);
|
|
|
|
parsetree->commandType = CMD_SELECT;
|
|
commandType = CMD_INSERT;
|
|
parsetree->resultRelation = 0;
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
limitOffset = parsetree->limitOffset;
|
|
limitCount = parsetree->limitCount;
|
|
|
|
/*
|
|
* 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_intersect_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
|
|
*/
|
|
n->lefthand = NIL;
|
|
foreach(elist, intersect_node->targetList)
|
|
{
|
|
TargetEntry *tent = (TargetEntry *) lfirst(elist);
|
|
|
|
n->lefthand = lappend(n->lefthand, tent->expr);
|
|
}
|
|
|
|
/*
|
|
* Also prepare the list of Opers that must be used for the
|
|
* comparisons (they depend on the specific datatypes involved!)
|
|
*/
|
|
left_expr = n->lefthand;
|
|
right_expr = ((Query *) (n->subselect))->targetList;
|
|
n->oper = NIL;
|
|
|
|
foreach(elist, left_expr)
|
|
{
|
|
Node *lexpr = lfirst(elist);
|
|
TargetEntry *tent = (TargetEntry *) lfirst(right_expr);
|
|
Operator optup;
|
|
Form_pg_operator opform;
|
|
Oper *newop;
|
|
|
|
optup = oper(op,
|
|
exprType(lexpr),
|
|
exprType(tent->expr),
|
|
FALSE);
|
|
opform = (Form_pg_operator) GETSTRUCT(optup);
|
|
|
|
if (opform->oprresult != BOOLOID)
|
|
elog(ERROR, "parser: '%s' must return 'bool' to be used with quantified predicate subquery", op);
|
|
|
|
newop = makeOper(oprid(optup),/* opno */
|
|
InvalidOid, /* opid */
|
|
opform->oprresult,
|
|
0,
|
|
NULL);
|
|
|
|
n->oper = lappend(n->oper, newop);
|
|
|
|
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)
|
|
AddHavingQual(intersect_node, (Node *) n);
|
|
else
|
|
AddQual(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;
|
|
result->limitOffset = limitOffset;
|
|
result->limitCount = limitCount;
|
|
|
|
/*
|
|
* 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 */
|
|
|
|
static void
|
|
create_intersect_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_intersect_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. */
|
|
static 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;
|
|
}
|