1996-07-09 08:22:35 +02:00
|
|
|
/*-------------------------------------------------------------------------
|
|
|
|
*
|
1999-02-14 00:22:53 +01:00
|
|
|
* rewriteManip.c
|
1996-07-09 08:22:35 +02:00
|
|
|
*
|
2001-01-24 20:43:33 +01:00
|
|
|
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
|
2000-01-26 06:58:53 +01:00
|
|
|
* Portions Copyright (c) 1994, Regents of the University of California
|
1996-07-09 08:22:35 +02:00
|
|
|
*
|
|
|
|
*
|
|
|
|
* IDENTIFICATION
|
2001-04-18 22:42:56 +02:00
|
|
|
* $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteManip.c,v 1.57 2001/04/18 20:42:55 tgl Exp $
|
1996-07-09 08:22:35 +02:00
|
|
|
*
|
|
|
|
*-------------------------------------------------------------------------
|
|
|
|
*/
|
|
|
|
#include "postgres.h"
|
|
|
|
|
2000-11-16 23:30:52 +01:00
|
|
|
#include "nodes/makefuncs.h"
|
1996-07-09 08:22:35 +02:00
|
|
|
#include "optimizer/clauses.h"
|
2000-01-27 19:11:50 +01:00
|
|
|
#include "optimizer/tlist.h"
|
1999-07-16 07:00:38 +02:00
|
|
|
#include "parser/parsetree.h"
|
1999-08-21 05:49:17 +02:00
|
|
|
#include "parser/parse_clause.h"
|
1999-07-16 07:00:38 +02:00
|
|
|
#include "rewrite/rewriteManip.h"
|
|
|
|
#include "utils/lsyscache.h"
|
1996-07-09 08:22:35 +02:00
|
|
|
|
|
|
|
|
1999-10-01 06:08:24 +02:00
|
|
|
/* macros borrowed from expression_tree_mutator */
|
1996-07-09 08:22:35 +02:00
|
|
|
|
1999-10-01 06:08:24 +02:00
|
|
|
#define FLATCOPY(newnode, node, nodetype) \
|
|
|
|
( (newnode) = makeNode(nodetype), \
|
|
|
|
memcpy((newnode), (node), sizeof(nodetype)) )
|
1998-10-21 18:21:29 +02:00
|
|
|
|
1999-10-01 06:08:24 +02:00
|
|
|
#define MUTATE(newfield, oldfield, fieldtype, mutator, context) \
|
|
|
|
( (newfield) = (fieldtype) mutator((Node *) (oldfield), (context)) )
|
1998-12-14 01:02:17 +01:00
|
|
|
|
2000-03-16 04:23:18 +01:00
|
|
|
static bool checkExprHasAggs_walker(Node *node, void *context);
|
|
|
|
static bool checkExprHasSubLink_walker(Node *node, void *context);
|
|
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
* checkExprHasAggs -
|
|
|
|
* Queries marked hasAggs might not have them any longer after
|
|
|
|
* rewriting. Check it.
|
|
|
|
*/
|
|
|
|
bool
|
|
|
|
checkExprHasAggs(Node *node)
|
|
|
|
{
|
2001-03-22 05:01:46 +01:00
|
|
|
|
2000-09-12 23:07:18 +02:00
|
|
|
/*
|
2001-03-22 05:01:46 +01:00
|
|
|
* If a Query is passed, examine it --- but we will not recurse into
|
|
|
|
* sub-Queries.
|
2000-09-12 23:07:18 +02:00
|
|
|
*/
|
|
|
|
if (node && IsA(node, Query))
|
|
|
|
return query_tree_walker((Query *) node, checkExprHasAggs_walker,
|
2000-10-05 21:11:39 +02:00
|
|
|
NULL, false);
|
2000-09-12 23:07:18 +02:00
|
|
|
else
|
|
|
|
return checkExprHasAggs_walker(node, NULL);
|
2000-03-16 04:23:18 +01:00
|
|
|
}
|
|
|
|
|
|
|
|
static bool
|
|
|
|
checkExprHasAggs_walker(Node *node, void *context)
|
|
|
|
{
|
|
|
|
if (node == NULL)
|
|
|
|
return false;
|
|
|
|
if (IsA(node, Aggref))
|
2000-04-12 19:17:23 +02:00
|
|
|
return true; /* abort the tree traversal and return
|
|
|
|
* true */
|
2000-03-16 04:23:18 +01:00
|
|
|
return expression_tree_walker(node, checkExprHasAggs_walker, context);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* checkExprHasSubLink -
|
|
|
|
* Queries marked hasSubLinks might not have them any longer after
|
|
|
|
* rewriting. Check it.
|
|
|
|
*/
|
|
|
|
bool
|
|
|
|
checkExprHasSubLink(Node *node)
|
|
|
|
{
|
2001-03-22 05:01:46 +01:00
|
|
|
|
2000-09-12 23:07:18 +02:00
|
|
|
/*
|
2001-03-22 05:01:46 +01:00
|
|
|
* If a Query is passed, examine it --- but we will not recurse into
|
|
|
|
* sub-Queries.
|
2000-09-12 23:07:18 +02:00
|
|
|
*/
|
|
|
|
if (node && IsA(node, Query))
|
|
|
|
return query_tree_walker((Query *) node, checkExprHasSubLink_walker,
|
2000-10-05 21:11:39 +02:00
|
|
|
NULL, false);
|
2000-09-12 23:07:18 +02:00
|
|
|
else
|
|
|
|
return checkExprHasSubLink_walker(node, NULL);
|
2000-03-16 04:23:18 +01:00
|
|
|
}
|
|
|
|
|
|
|
|
static bool
|
|
|
|
checkExprHasSubLink_walker(Node *node, void *context)
|
|
|
|
{
|
|
|
|
if (node == NULL)
|
|
|
|
return false;
|
|
|
|
if (IsA(node, SubLink))
|
2000-04-12 19:17:23 +02:00
|
|
|
return true; /* abort the tree traversal and return
|
|
|
|
* true */
|
2000-03-16 04:23:18 +01:00
|
|
|
return expression_tree_walker(node, checkExprHasSubLink_walker, context);
|
|
|
|
}
|
|
|
|
|
1998-12-14 01:02:17 +01:00
|
|
|
|
1999-10-01 06:08:24 +02:00
|
|
|
/*
|
|
|
|
* OffsetVarNodes - adjust Vars when appending one query's RT to another
|
|
|
|
*
|
|
|
|
* Find all Var nodes in the given tree with varlevelsup == sublevels_up,
|
|
|
|
* and increment their varno fields (rangetable indexes) by 'offset'.
|
2001-03-22 05:01:46 +01:00
|
|
|
* The varnoold fields are adjusted similarly. Also, RangeTblRef nodes
|
2000-10-05 21:11:39 +02:00
|
|
|
* in join trees and setOp trees are adjusted.
|
1999-10-01 06:08:24 +02:00
|
|
|
*
|
|
|
|
* NOTE: although this has the form of a walker, we cheat and modify the
|
2000-09-12 23:07:18 +02:00
|
|
|
* nodes in-place. The given expression tree should have been copied
|
1999-10-01 06:08:24 +02:00
|
|
|
* earlier to ensure that no unwanted side-effects occur!
|
|
|
|
*/
|
1998-12-14 01:02:17 +01:00
|
|
|
|
2000-04-12 19:17:23 +02:00
|
|
|
typedef struct
|
|
|
|
{
|
1999-10-01 06:08:24 +02:00
|
|
|
int offset;
|
|
|
|
int sublevels_up;
|
|
|
|
} OffsetVarNodes_context;
|
1998-10-21 18:21:29 +02:00
|
|
|
|
1999-10-01 06:08:24 +02:00
|
|
|
static bool
|
|
|
|
OffsetVarNodes_walker(Node *node, OffsetVarNodes_context *context)
|
|
|
|
{
|
|
|
|
if (node == NULL)
|
|
|
|
return false;
|
|
|
|
if (IsA(node, Var))
|
|
|
|
{
|
|
|
|
Var *var = (Var *) node;
|
1998-10-21 18:21:29 +02:00
|
|
|
|
1999-10-01 06:08:24 +02:00
|
|
|
if (var->varlevelsup == context->sublevels_up)
|
|
|
|
{
|
|
|
|
var->varno += context->offset;
|
|
|
|
var->varnoold += context->offset;
|
|
|
|
}
|
|
|
|
return false;
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
2000-09-12 23:07:18 +02:00
|
|
|
if (IsA(node, RangeTblRef))
|
1999-10-01 06:08:24 +02:00
|
|
|
{
|
2001-03-22 05:01:46 +01:00
|
|
|
RangeTblRef *rtr = (RangeTblRef *) node;
|
2000-04-12 19:17:23 +02:00
|
|
|
|
2000-09-12 23:07:18 +02:00
|
|
|
if (context->sublevels_up == 0)
|
|
|
|
rtr->rtindex += context->offset;
|
2000-10-05 21:11:39 +02:00
|
|
|
/* the subquery itself is visited separately */
|
1999-10-01 06:08:24 +02:00
|
|
|
return false;
|
|
|
|
}
|
|
|
|
if (IsA(node, Query))
|
|
|
|
{
|
2000-09-12 23:07:18 +02:00
|
|
|
/* Recurse into subselects */
|
|
|
|
bool result;
|
1999-10-01 06:08:24 +02:00
|
|
|
|
2000-09-12 23:07:18 +02:00
|
|
|
context->sublevels_up++;
|
|
|
|
result = query_tree_walker((Query *) node, OffsetVarNodes_walker,
|
2000-10-05 21:11:39 +02:00
|
|
|
(void *) context, true);
|
2000-09-12 23:07:18 +02:00
|
|
|
context->sublevels_up--;
|
|
|
|
return result;
|
1999-10-01 06:08:24 +02:00
|
|
|
}
|
|
|
|
return expression_tree_walker(node, OffsetVarNodes_walker,
|
|
|
|
(void *) context);
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
void
|
1999-10-01 06:08:24 +02:00
|
|
|
OffsetVarNodes(Node *node, int offset, int sublevels_up)
|
1996-07-09 08:22:35 +02:00
|
|
|
{
|
1999-10-01 06:08:24 +02:00
|
|
|
OffsetVarNodes_context context;
|
1998-10-21 18:21:29 +02:00
|
|
|
|
1999-10-01 06:08:24 +02:00
|
|
|
context.offset = offset;
|
|
|
|
context.sublevels_up = sublevels_up;
|
2000-09-12 23:07:18 +02:00
|
|
|
|
|
|
|
/*
|
|
|
|
* Must be prepared to start with a Query or a bare expression tree;
|
|
|
|
* if it's a Query, go straight to query_tree_walker to make sure that
|
|
|
|
* sublevels_up doesn't get incremented prematurely.
|
|
|
|
*/
|
|
|
|
if (node && IsA(node, Query))
|
2000-12-07 00:55:19 +01:00
|
|
|
{
|
2001-03-22 05:01:46 +01:00
|
|
|
Query *qry = (Query *) node;
|
|
|
|
List *l;
|
2000-12-07 00:55:19 +01:00
|
|
|
|
|
|
|
/*
|
2001-03-22 05:01:46 +01:00
|
|
|
* If we are starting at a Query, and sublevels_up is zero, then
|
|
|
|
* we must also fix rangetable indexes in the Query itself ---
|
|
|
|
* namely resultRelation and rowMarks entries. sublevels_up
|
|
|
|
* cannot be zero when recursing into a subquery, so there's no
|
|
|
|
* need to have the same logic inside OffsetVarNodes_walker.
|
2000-12-07 00:55:19 +01:00
|
|
|
*/
|
|
|
|
if (sublevels_up == 0)
|
|
|
|
{
|
|
|
|
if (qry->resultRelation)
|
|
|
|
qry->resultRelation += offset;
|
|
|
|
foreach(l, qry->rowMarks)
|
|
|
|
lfirsti(l) += offset;
|
|
|
|
}
|
|
|
|
query_tree_walker(qry, OffsetVarNodes_walker,
|
2000-10-05 21:11:39 +02:00
|
|
|
(void *) &context, true);
|
2000-12-07 00:55:19 +01:00
|
|
|
}
|
2000-09-12 23:07:18 +02:00
|
|
|
else
|
|
|
|
OffsetVarNodes_walker(node, &context);
|
1999-10-01 06:08:24 +02:00
|
|
|
}
|
1998-12-14 01:02:17 +01:00
|
|
|
|
1999-10-01 06:08:24 +02:00
|
|
|
/*
|
|
|
|
* ChangeVarNodes - adjust Var nodes for a specific change of RT index
|
|
|
|
*
|
|
|
|
* Find all Var nodes in the given tree belonging to a specific relation
|
|
|
|
* (identified by sublevels_up and rt_index), and change their varno fields
|
2000-09-12 23:07:18 +02:00
|
|
|
* to 'new_index'. The varnoold fields are changed too. Also, RangeTblRef
|
2000-10-05 21:11:39 +02:00
|
|
|
* nodes in join trees and setOp trees are adjusted.
|
1999-10-01 06:08:24 +02:00
|
|
|
*
|
|
|
|
* NOTE: although this has the form of a walker, we cheat and modify the
|
2000-09-12 23:07:18 +02:00
|
|
|
* nodes in-place. The given expression tree should have been copied
|
1999-10-01 06:08:24 +02:00
|
|
|
* earlier to ensure that no unwanted side-effects occur!
|
|
|
|
*/
|
1998-12-14 01:02:17 +01:00
|
|
|
|
2000-04-12 19:17:23 +02:00
|
|
|
typedef struct
|
|
|
|
{
|
1999-10-01 06:08:24 +02:00
|
|
|
int rt_index;
|
|
|
|
int new_index;
|
|
|
|
int sublevels_up;
|
|
|
|
} ChangeVarNodes_context;
|
1998-10-21 18:21:29 +02:00
|
|
|
|
1999-10-01 06:08:24 +02:00
|
|
|
static bool
|
|
|
|
ChangeVarNodes_walker(Node *node, ChangeVarNodes_context *context)
|
|
|
|
{
|
|
|
|
if (node == NULL)
|
|
|
|
return false;
|
|
|
|
if (IsA(node, Var))
|
|
|
|
{
|
|
|
|
Var *var = (Var *) node;
|
1998-10-21 18:21:29 +02:00
|
|
|
|
1999-10-01 06:08:24 +02:00
|
|
|
if (var->varlevelsup == context->sublevels_up &&
|
|
|
|
var->varno == context->rt_index)
|
|
|
|
{
|
|
|
|
var->varno = context->new_index;
|
|
|
|
var->varnoold = context->new_index;
|
|
|
|
}
|
|
|
|
return false;
|
|
|
|
}
|
2000-09-12 23:07:18 +02:00
|
|
|
if (IsA(node, RangeTblRef))
|
1999-10-01 06:08:24 +02:00
|
|
|
{
|
2001-03-22 05:01:46 +01:00
|
|
|
RangeTblRef *rtr = (RangeTblRef *) node;
|
2000-04-12 19:17:23 +02:00
|
|
|
|
2000-09-12 23:07:18 +02:00
|
|
|
if (context->sublevels_up == 0 &&
|
|
|
|
rtr->rtindex == context->rt_index)
|
|
|
|
rtr->rtindex = context->new_index;
|
2000-10-05 21:11:39 +02:00
|
|
|
/* the subquery itself is visited separately */
|
1999-10-01 06:08:24 +02:00
|
|
|
return false;
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
1999-10-01 06:08:24 +02:00
|
|
|
if (IsA(node, Query))
|
|
|
|
{
|
2000-09-12 23:07:18 +02:00
|
|
|
/* Recurse into subselects */
|
|
|
|
bool result;
|
1999-10-01 06:08:24 +02:00
|
|
|
|
2000-09-12 23:07:18 +02:00
|
|
|
context->sublevels_up++;
|
|
|
|
result = query_tree_walker((Query *) node, ChangeVarNodes_walker,
|
2000-10-05 21:11:39 +02:00
|
|
|
(void *) context, true);
|
2000-09-12 23:07:18 +02:00
|
|
|
context->sublevels_up--;
|
|
|
|
return result;
|
1999-10-01 06:08:24 +02:00
|
|
|
}
|
|
|
|
return expression_tree_walker(node, ChangeVarNodes_walker,
|
|
|
|
(void *) context);
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
|
|
|
|
1999-10-01 06:08:24 +02:00
|
|
|
void
|
|
|
|
ChangeVarNodes(Node *node, int rt_index, int new_index, int sublevels_up)
|
|
|
|
{
|
|
|
|
ChangeVarNodes_context context;
|
1998-10-21 18:21:29 +02:00
|
|
|
|
1999-10-01 06:08:24 +02:00
|
|
|
context.rt_index = rt_index;
|
|
|
|
context.new_index = new_index;
|
|
|
|
context.sublevels_up = sublevels_up;
|
2000-09-12 23:07:18 +02:00
|
|
|
|
|
|
|
/*
|
|
|
|
* Must be prepared to start with a Query or a bare expression tree;
|
|
|
|
* if it's a Query, go straight to query_tree_walker to make sure that
|
|
|
|
* sublevels_up doesn't get incremented prematurely.
|
|
|
|
*/
|
|
|
|
if (node && IsA(node, Query))
|
2000-12-07 00:55:19 +01:00
|
|
|
{
|
2001-03-22 05:01:46 +01:00
|
|
|
Query *qry = (Query *) node;
|
|
|
|
List *l;
|
2000-12-07 00:55:19 +01:00
|
|
|
|
|
|
|
/*
|
2001-03-22 05:01:46 +01:00
|
|
|
* If we are starting at a Query, and sublevels_up is zero, then
|
|
|
|
* we must also fix rangetable indexes in the Query itself ---
|
|
|
|
* namely resultRelation and rowMarks entries. sublevels_up
|
|
|
|
* cannot be zero when recursing into a subquery, so there's no
|
|
|
|
* need to have the same logic inside ChangeVarNodes_walker.
|
2000-12-07 00:55:19 +01:00
|
|
|
*/
|
|
|
|
if (sublevels_up == 0)
|
|
|
|
{
|
|
|
|
if (qry->resultRelation == rt_index)
|
|
|
|
qry->resultRelation = new_index;
|
|
|
|
foreach(l, qry->rowMarks)
|
|
|
|
{
|
|
|
|
if (lfirsti(l) == rt_index)
|
|
|
|
lfirsti(l) = new_index;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
query_tree_walker(qry, ChangeVarNodes_walker,
|
2000-10-05 21:11:39 +02:00
|
|
|
(void *) &context, true);
|
2000-12-07 00:55:19 +01:00
|
|
|
}
|
2000-09-12 23:07:18 +02:00
|
|
|
else
|
|
|
|
ChangeVarNodes_walker(node, &context);
|
1999-10-01 06:08:24 +02:00
|
|
|
}
|
1998-10-21 18:21:29 +02:00
|
|
|
|
2000-03-16 04:23:18 +01:00
|
|
|
/*
|
|
|
|
* IncrementVarSublevelsUp - adjust Var nodes when pushing them down in tree
|
|
|
|
*
|
|
|
|
* Find all Var nodes in the given tree having varlevelsup >= min_sublevels_up,
|
|
|
|
* and add delta_sublevels_up to their varlevelsup value. This is needed when
|
|
|
|
* an expression that's correct for some nesting level is inserted into a
|
|
|
|
* subquery. Ordinarily the initial call has min_sublevels_up == 0 so that
|
|
|
|
* all Vars are affected. The point of min_sublevels_up is that we can
|
|
|
|
* increment it when we recurse into a sublink, so that local variables in
|
|
|
|
* that sublink are not affected, only outer references to vars that belong
|
|
|
|
* to the expression's original query level or parents thereof.
|
|
|
|
*
|
|
|
|
* NOTE: although this has the form of a walker, we cheat and modify the
|
2000-04-12 19:17:23 +02:00
|
|
|
* Var nodes in-place. The given expression tree should have been copied
|
2000-03-16 04:23:18 +01:00
|
|
|
* earlier to ensure that no unwanted side-effects occur!
|
|
|
|
*/
|
|
|
|
|
2000-04-12 19:17:23 +02:00
|
|
|
typedef struct
|
|
|
|
{
|
2000-03-16 04:23:18 +01:00
|
|
|
int delta_sublevels_up;
|
|
|
|
int min_sublevels_up;
|
|
|
|
} IncrementVarSublevelsUp_context;
|
|
|
|
|
|
|
|
static bool
|
|
|
|
IncrementVarSublevelsUp_walker(Node *node,
|
|
|
|
IncrementVarSublevelsUp_context *context)
|
|
|
|
{
|
|
|
|
if (node == NULL)
|
|
|
|
return false;
|
|
|
|
if (IsA(node, Var))
|
|
|
|
{
|
|
|
|
Var *var = (Var *) node;
|
|
|
|
|
|
|
|
if (var->varlevelsup >= context->min_sublevels_up)
|
|
|
|
var->varlevelsup += context->delta_sublevels_up;
|
|
|
|
return false;
|
|
|
|
}
|
2000-09-12 23:07:18 +02:00
|
|
|
if (IsA(node, Query))
|
2000-03-16 04:23:18 +01:00
|
|
|
{
|
2000-09-12 23:07:18 +02:00
|
|
|
/* Recurse into subselects */
|
|
|
|
bool result;
|
2000-04-12 19:17:23 +02:00
|
|
|
|
2000-09-12 23:07:18 +02:00
|
|
|
context->min_sublevels_up++;
|
|
|
|
result = query_tree_walker((Query *) node,
|
|
|
|
IncrementVarSublevelsUp_walker,
|
2000-10-05 21:11:39 +02:00
|
|
|
(void *) context, true);
|
2000-09-12 23:07:18 +02:00
|
|
|
context->min_sublevels_up--;
|
|
|
|
return result;
|
|
|
|
}
|
|
|
|
return expression_tree_walker(node, IncrementVarSublevelsUp_walker,
|
|
|
|
(void *) context);
|
|
|
|
}
|
|
|
|
|
|
|
|
void
|
|
|
|
IncrementVarSublevelsUp(Node *node, int delta_sublevels_up,
|
|
|
|
int min_sublevels_up)
|
|
|
|
{
|
|
|
|
IncrementVarSublevelsUp_context context;
|
|
|
|
|
|
|
|
context.delta_sublevels_up = delta_sublevels_up;
|
|
|
|
context.min_sublevels_up = min_sublevels_up;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Must be prepared to start with a Query or a bare expression tree;
|
|
|
|
* if it's a Query, go straight to query_tree_walker to make sure that
|
|
|
|
* sublevels_up doesn't get incremented prematurely.
|
|
|
|
*/
|
|
|
|
if (node && IsA(node, Query))
|
|
|
|
query_tree_walker((Query *) node, IncrementVarSublevelsUp_walker,
|
2000-10-05 21:11:39 +02:00
|
|
|
(void *) &context, true);
|
2000-09-12 23:07:18 +02:00
|
|
|
else
|
|
|
|
IncrementVarSublevelsUp_walker(node, &context);
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
* rangeTableEntry_used - detect whether an RTE is referenced somewhere
|
2000-10-05 21:11:39 +02:00
|
|
|
* in var nodes or join or setOp trees of a query or expression.
|
2000-09-12 23:07:18 +02:00
|
|
|
*/
|
|
|
|
|
|
|
|
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;
|
2000-03-16 04:23:18 +01:00
|
|
|
|
2000-09-12 23:07:18 +02:00
|
|
|
if (var->varlevelsup == context->sublevels_up &&
|
|
|
|
var->varno == context->rt_index)
|
2000-03-16 04:23:18 +01:00
|
|
|
return true;
|
|
|
|
return false;
|
|
|
|
}
|
2000-09-12 23:07:18 +02:00
|
|
|
if (IsA(node, RangeTblRef))
|
2000-03-16 04:23:18 +01:00
|
|
|
{
|
2000-09-12 23:07:18 +02:00
|
|
|
RangeTblRef *rtr = (RangeTblRef *) node;
|
2000-03-16 04:23:18 +01:00
|
|
|
|
2000-09-12 23:07:18 +02:00
|
|
|
if (rtr->rtindex == context->rt_index &&
|
|
|
|
context->sublevels_up == 0)
|
2000-03-16 04:23:18 +01:00
|
|
|
return true;
|
2000-10-05 21:11:39 +02:00
|
|
|
/* the subquery itself is visited separately */
|
2000-09-12 23:07:18 +02:00
|
|
|
return false;
|
|
|
|
}
|
|
|
|
if (IsA(node, Query))
|
|
|
|
{
|
|
|
|
/* Recurse into subselects */
|
|
|
|
bool result;
|
|
|
|
|
|
|
|
context->sublevels_up++;
|
|
|
|
result = query_tree_walker((Query *) node, rangeTableEntry_used_walker,
|
2000-10-05 21:11:39 +02:00
|
|
|
(void *) context, true);
|
2000-09-12 23:07:18 +02:00
|
|
|
context->sublevels_up--;
|
|
|
|
return result;
|
|
|
|
}
|
|
|
|
return expression_tree_walker(node, rangeTableEntry_used_walker,
|
|
|
|
(void *) context);
|
|
|
|
}
|
|
|
|
|
|
|
|
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;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Must be prepared to start with a Query or a bare expression tree;
|
|
|
|
* if it's a Query, go straight to query_tree_walker to make sure that
|
|
|
|
* sublevels_up doesn't get incremented prematurely.
|
|
|
|
*/
|
|
|
|
if (node && IsA(node, Query))
|
|
|
|
return query_tree_walker((Query *) node, rangeTableEntry_used_walker,
|
2000-10-05 21:11:39 +02:00
|
|
|
(void *) &context, true);
|
2000-09-12 23:07:18 +02:00
|
|
|
else
|
|
|
|
return rangeTableEntry_used_walker(node, &context);
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
* attribute_used -
|
|
|
|
* Check if a specific attribute number of a RTE is used
|
|
|
|
* somewhere in the query or expression.
|
|
|
|
*/
|
|
|
|
|
|
|
|
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)
|
2000-03-16 04:23:18 +01:00
|
|
|
return true;
|
|
|
|
return false;
|
|
|
|
}
|
2000-09-12 23:07:18 +02:00
|
|
|
if (IsA(node, Query))
|
|
|
|
{
|
|
|
|
/* Recurse into subselects */
|
|
|
|
bool result;
|
|
|
|
|
|
|
|
context->sublevels_up++;
|
|
|
|
result = query_tree_walker((Query *) node, attribute_used_walker,
|
2000-10-05 21:11:39 +02:00
|
|
|
(void *) context, true);
|
2000-09-12 23:07:18 +02:00
|
|
|
context->sublevels_up--;
|
|
|
|
return result;
|
|
|
|
}
|
|
|
|
return expression_tree_walker(node, attribute_used_walker,
|
2000-03-16 04:23:18 +01:00
|
|
|
(void *) context);
|
|
|
|
}
|
|
|
|
|
2000-09-12 23:07:18 +02:00
|
|
|
bool
|
|
|
|
attribute_used(Node *node, int rt_index, int attno, int sublevels_up)
|
2000-03-16 04:23:18 +01:00
|
|
|
{
|
2000-09-12 23:07:18 +02:00
|
|
|
attribute_used_context context;
|
2000-03-16 04:23:18 +01:00
|
|
|
|
2000-09-12 23:07:18 +02:00
|
|
|
context.rt_index = rt_index;
|
|
|
|
context.attno = attno;
|
|
|
|
context.sublevels_up = sublevels_up;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Must be prepared to start with a Query or a bare expression tree;
|
|
|
|
* if it's a Query, go straight to query_tree_walker to make sure that
|
|
|
|
* sublevels_up doesn't get incremented prematurely.
|
|
|
|
*/
|
|
|
|
if (node && IsA(node, Query))
|
|
|
|
return query_tree_walker((Query *) node, attribute_used_walker,
|
2000-10-05 21:11:39 +02:00
|
|
|
(void *) &context, true);
|
2000-09-12 23:07:18 +02:00
|
|
|
else
|
|
|
|
return attribute_used_walker(node, &context);
|
2000-03-16 04:23:18 +01:00
|
|
|
}
|
|
|
|
|
2000-09-12 23:07:18 +02:00
|
|
|
|
2000-12-05 20:15:10 +01:00
|
|
|
/*
|
|
|
|
* If the given Query is an INSERT ... SELECT construct, extract and
|
|
|
|
* return the sub-Query node that represents the SELECT part. Otherwise
|
|
|
|
* return the given Query.
|
|
|
|
*
|
|
|
|
* If subquery_ptr is not NULL, then *subquery_ptr is set to the location
|
|
|
|
* of the link to the SELECT subquery inside parsetree, or NULL if not an
|
|
|
|
* INSERT ... SELECT.
|
|
|
|
*
|
|
|
|
* This is a hack needed because transformations on INSERT ... SELECTs that
|
|
|
|
* appear in rule actions should be applied to the source SELECT, not to the
|
|
|
|
* INSERT part. Perhaps this can be cleaned up with redesigned querytrees.
|
|
|
|
*/
|
|
|
|
Query *
|
|
|
|
getInsertSelectQuery(Query *parsetree, Query ***subquery_ptr)
|
|
|
|
{
|
|
|
|
Query *selectquery;
|
|
|
|
RangeTblEntry *selectrte;
|
|
|
|
RangeTblRef *rtr;
|
|
|
|
|
|
|
|
if (subquery_ptr)
|
|
|
|
*subquery_ptr = NULL;
|
|
|
|
|
|
|
|
if (parsetree == NULL)
|
|
|
|
return parsetree;
|
|
|
|
if (parsetree->commandType != CMD_INSERT)
|
|
|
|
return parsetree;
|
2001-03-22 05:01:46 +01:00
|
|
|
|
2000-12-05 20:15:10 +01:00
|
|
|
/*
|
2001-03-22 05:01:46 +01:00
|
|
|
* Currently, this is ONLY applied to rule-action queries, and so we
|
|
|
|
* expect to find the *OLD* and *NEW* placeholder entries in the given
|
|
|
|
* query. If they're not there, it must be an INSERT/SELECT in which
|
|
|
|
* they've been pushed down to the SELECT.
|
2000-12-05 20:15:10 +01:00
|
|
|
*/
|
|
|
|
if (length(parsetree->rtable) >= 2 &&
|
|
|
|
strcmp(rt_fetch(PRS2_OLD_VARNO, parsetree->rtable)->eref->relname,
|
|
|
|
"*OLD*") == 0 &&
|
|
|
|
strcmp(rt_fetch(PRS2_NEW_VARNO, parsetree->rtable)->eref->relname,
|
|
|
|
"*NEW*") == 0)
|
|
|
|
return parsetree;
|
|
|
|
Assert(parsetree->jointree && IsA(parsetree->jointree, FromExpr));
|
|
|
|
if (length(parsetree->jointree->fromlist) != 1)
|
|
|
|
elog(ERROR, "getInsertSelectQuery: expected to find SELECT subquery");
|
|
|
|
rtr = (RangeTblRef *) lfirst(parsetree->jointree->fromlist);
|
|
|
|
Assert(IsA(rtr, RangeTblRef));
|
|
|
|
selectrte = rt_fetch(rtr->rtindex, parsetree->rtable);
|
|
|
|
selectquery = selectrte->subquery;
|
2001-03-22 05:01:46 +01:00
|
|
|
if (!(selectquery && IsA(selectquery, Query) &&
|
|
|
|
selectquery->commandType == CMD_SELECT))
|
2000-12-05 20:15:10 +01:00
|
|
|
elog(ERROR, "getInsertSelectQuery: expected to find SELECT subquery");
|
|
|
|
if (length(selectquery->rtable) >= 2 &&
|
2001-03-22 05:01:46 +01:00
|
|
|
strcmp(rt_fetch(PRS2_OLD_VARNO, selectquery->rtable)->eref->relname,
|
|
|
|
"*OLD*") == 0 &&
|
|
|
|
strcmp(rt_fetch(PRS2_NEW_VARNO, selectquery->rtable)->eref->relname,
|
|
|
|
"*NEW*") == 0)
|
2000-12-05 20:15:10 +01:00
|
|
|
{
|
|
|
|
if (subquery_ptr)
|
2001-03-22 05:01:46 +01:00
|
|
|
*subquery_ptr = &(selectrte->subquery);
|
2000-12-05 20:15:10 +01:00
|
|
|
return selectquery;
|
|
|
|
}
|
|
|
|
elog(ERROR, "getInsertSelectQuery: can't find rule placeholders");
|
|
|
|
return NULL; /* not reached */
|
|
|
|
}
|
|
|
|
|
|
|
|
|
1999-10-01 06:08:24 +02:00
|
|
|
/*
|
|
|
|
* Add the given qualifier condition to the query's WHERE clause
|
|
|
|
*/
|
1996-07-09 08:22:35 +02:00
|
|
|
void
|
1997-09-08 23:56:23 +02:00
|
|
|
AddQual(Query *parsetree, Node *qual)
|
1996-07-09 08:22:35 +02:00
|
|
|
{
|
2000-09-29 20:21:41 +02:00
|
|
|
Node *copy;
|
1997-09-07 07:04:48 +02:00
|
|
|
|
|
|
|
if (qual == NULL)
|
|
|
|
return;
|
|
|
|
|
2001-01-27 02:44:20 +01:00
|
|
|
if (parsetree->commandType == CMD_UTILITY)
|
|
|
|
{
|
2001-03-22 05:01:46 +01:00
|
|
|
|
2001-01-27 02:44:20 +01:00
|
|
|
/*
|
|
|
|
* Noplace to put the qual on a utility statement.
|
|
|
|
*
|
2001-03-22 05:01:46 +01:00
|
|
|
* For now, we expect utility stmt to be a NOTIFY, so give a specific
|
|
|
|
* error message for that case.
|
2001-01-27 02:44:20 +01:00
|
|
|
*/
|
|
|
|
if (parsetree->utilityStmt && IsA(parsetree->utilityStmt, NotifyStmt))
|
|
|
|
elog(ERROR, "Conditional NOTIFY is not implemented");
|
|
|
|
else
|
|
|
|
elog(ERROR, "Conditional utility statements are not implemented");
|
|
|
|
}
|
|
|
|
|
1999-02-08 02:39:46 +01:00
|
|
|
/* INTERSECT want's the original, but we need to copy - Jan */
|
|
|
|
copy = copyObject(qual);
|
Hi!
INTERSECT and EXCEPT is available for postgresql-v6.4!
The patch against v6.4 is included at the end of the current text
(in uuencoded form!)
I also included the text of my Master's Thesis. (a postscript
version). I hope that you find something of it useful and would be
happy if parts of it find their way into the PostgreSQL documentation
project (If so, tell me, then I send the sources of the document!)
The contents of the document are:
-) The first chapter might be of less interest as it gives only an
overview on SQL.
-) The second chapter gives a description on much of PostgreSQL's
features (like user defined types etc. and how to use these features)
-) The third chapter starts with an overview of PostgreSQL's internal
structure with focus on the stages a query has to pass (i.e. parser,
planner/optimizer, executor). Then a detailed description of the
implementation of the Having clause and the Intersect/Except logic is
given.
Originally I worked on v6.3.2 but never found time enough to prepare
and post a patch. Now I applied the changes to v6.4 to get Intersect
and Except working with the new version. Chapter 3 of my documentation
deals with the changes against v6.3.2, so keep that in mind when
comparing the parts of the code printed there with the patched sources
of v6.4.
Here are some remarks on the patch. There are some things that have
still to be done but at the moment I don't have time to do them
myself. (I'm doing my military service at the moment) Sorry for that
:-(
-) I used a rewrite technique for the implementation of the Except/Intersect
logic which rewrites the query to a semantically equivalent query before
it is handed to the rewrite system (for views, rules etc.), planner,
executor etc.
-) In v6.3.2 the types of the attributes of two select statements
connected by the UNION keyword had to match 100%. In v6.4 the types
only need to be familiar (i.e. int and float can be mixed). Since this
feature did not exist when I worked on Intersect/Except it
does not work correctly for Except/Intersect queries WHEN USED IN
COMBINATION WITH UNIONS! (i.e. sometimes the wrong type is used for the
resulting table. This is because until now the types of the attributes of
the first select statement have been used for the resulting table.
When Intersects and/or Excepts are used in combination with Unions it
might happen, that the first select statement of the original query
appears at another position in the query which will be executed. The reason
for this is the technique used for the implementation of
Except/Intersect which does a query rewrite!)
NOTE: It is NOT broken for pure UNION queries and pure INTERSECT/EXCEPT
queries!!!
-) I had to add the field intersect_clause to some data structures
but did not find time to implement printfuncs for the new field.
This does NOT break the debug modes but when an Except/Intersect
is used the query debug output will be the already rewritten query.
-) Massive changes to the grammar rules for SELECT and INSERT statements
have been necessary (see comments in gram.y and documentation for
deatails) in order to be able to use mixed queries like
(SELECT ... UNION (SELECT ... EXCEPT SELECT)) INTERSECT SELECT...;
-) When using UNION/EXCEPT/INTERSECT you will get:
NOTICE: equal: "Don't know if nodes of type xxx are equal".
I did not have time to add comparsion support for all the needed nodes,
but the default behaviour of the function equal met my requirements.
I did not dare to supress this message!
That's the reason why the regression test for union will fail: These
messages are also included in the union.out file!
-) Somebody of you changed the union_planner() function for v6.4
(I copied the targetlist to new_tlist and that was removed and
replaced by a cleanup of the original targetlist). These chnages
violated some having queries executed against views so I changed
it back again. I did not have time to examine the differences between the
two versions but now it works :-)
If you want to find out, try the file queries/view_having.sql on
both versions and compare the results . Two queries won't produce a
correct result with your version.
regards
Stefan
1999-01-18 01:10:17 +01:00
|
|
|
|
2000-09-29 20:21:41 +02:00
|
|
|
parsetree->jointree->quals = make_and_qual(parsetree->jointree->quals,
|
|
|
|
copy);
|
2000-03-16 04:23:18 +01:00
|
|
|
|
|
|
|
/*
|
|
|
|
* Make sure query is marked correctly if added qual has sublinks or
|
2000-04-12 19:17:23 +02:00
|
|
|
* aggregates (not sure it can ever have aggs, but sublinks
|
|
|
|
* definitely).
|
2000-03-16 04:23:18 +01:00
|
|
|
*/
|
|
|
|
parsetree->hasAggs |= checkExprHasAggs(copy);
|
|
|
|
parsetree->hasSubLinks |= checkExprHasSubLink(copy);
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
|
|
|
|
1999-10-01 06:08:24 +02:00
|
|
|
/*
|
|
|
|
* Add the given havingQual to the one already contained in the parsetree
|
|
|
|
* just as AddQual does for the normal 'where' qual
|
|
|
|
*/
|
1998-07-19 07:49:26 +02:00
|
|
|
void
|
|
|
|
AddHavingQual(Query *parsetree, Node *havingQual)
|
|
|
|
{
|
2000-09-29 20:21:41 +02:00
|
|
|
Node *copy;
|
1998-07-19 07:49:26 +02:00
|
|
|
|
|
|
|
if (havingQual == NULL)
|
|
|
|
return;
|
|
|
|
|
2001-01-27 02:44:20 +01:00
|
|
|
if (parsetree->commandType == CMD_UTILITY)
|
|
|
|
{
|
2001-03-22 05:01:46 +01:00
|
|
|
|
2001-01-27 02:44:20 +01:00
|
|
|
/*
|
|
|
|
* Noplace to put the qual on a utility statement.
|
|
|
|
*
|
2001-03-22 05:01:46 +01:00
|
|
|
* For now, we expect utility stmt to be a NOTIFY, so give a specific
|
|
|
|
* error message for that case.
|
2001-01-27 02:44:20 +01:00
|
|
|
*/
|
|
|
|
if (parsetree->utilityStmt && IsA(parsetree->utilityStmt, NotifyStmt))
|
|
|
|
elog(ERROR, "Conditional NOTIFY is not implemented");
|
|
|
|
else
|
|
|
|
elog(ERROR, "Conditional utility statements are not implemented");
|
|
|
|
}
|
|
|
|
|
1999-02-08 02:39:46 +01:00
|
|
|
/* INTERSECT want's the original, but we need to copy - Jan */
|
|
|
|
copy = copyObject(havingQual);
|
Hi!
INTERSECT and EXCEPT is available for postgresql-v6.4!
The patch against v6.4 is included at the end of the current text
(in uuencoded form!)
I also included the text of my Master's Thesis. (a postscript
version). I hope that you find something of it useful and would be
happy if parts of it find their way into the PostgreSQL documentation
project (If so, tell me, then I send the sources of the document!)
The contents of the document are:
-) The first chapter might be of less interest as it gives only an
overview on SQL.
-) The second chapter gives a description on much of PostgreSQL's
features (like user defined types etc. and how to use these features)
-) The third chapter starts with an overview of PostgreSQL's internal
structure with focus on the stages a query has to pass (i.e. parser,
planner/optimizer, executor). Then a detailed description of the
implementation of the Having clause and the Intersect/Except logic is
given.
Originally I worked on v6.3.2 but never found time enough to prepare
and post a patch. Now I applied the changes to v6.4 to get Intersect
and Except working with the new version. Chapter 3 of my documentation
deals with the changes against v6.3.2, so keep that in mind when
comparing the parts of the code printed there with the patched sources
of v6.4.
Here are some remarks on the patch. There are some things that have
still to be done but at the moment I don't have time to do them
myself. (I'm doing my military service at the moment) Sorry for that
:-(
-) I used a rewrite technique for the implementation of the Except/Intersect
logic which rewrites the query to a semantically equivalent query before
it is handed to the rewrite system (for views, rules etc.), planner,
executor etc.
-) In v6.3.2 the types of the attributes of two select statements
connected by the UNION keyword had to match 100%. In v6.4 the types
only need to be familiar (i.e. int and float can be mixed). Since this
feature did not exist when I worked on Intersect/Except it
does not work correctly for Except/Intersect queries WHEN USED IN
COMBINATION WITH UNIONS! (i.e. sometimes the wrong type is used for the
resulting table. This is because until now the types of the attributes of
the first select statement have been used for the resulting table.
When Intersects and/or Excepts are used in combination with Unions it
might happen, that the first select statement of the original query
appears at another position in the query which will be executed. The reason
for this is the technique used for the implementation of
Except/Intersect which does a query rewrite!)
NOTE: It is NOT broken for pure UNION queries and pure INTERSECT/EXCEPT
queries!!!
-) I had to add the field intersect_clause to some data structures
but did not find time to implement printfuncs for the new field.
This does NOT break the debug modes but when an Except/Intersect
is used the query debug output will be the already rewritten query.
-) Massive changes to the grammar rules for SELECT and INSERT statements
have been necessary (see comments in gram.y and documentation for
deatails) in order to be able to use mixed queries like
(SELECT ... UNION (SELECT ... EXCEPT SELECT)) INTERSECT SELECT...;
-) When using UNION/EXCEPT/INTERSECT you will get:
NOTICE: equal: "Don't know if nodes of type xxx are equal".
I did not have time to add comparsion support for all the needed nodes,
but the default behaviour of the function equal met my requirements.
I did not dare to supress this message!
That's the reason why the regression test for union will fail: These
messages are also included in the union.out file!
-) Somebody of you changed the union_planner() function for v6.4
(I copied the targetlist to new_tlist and that was removed and
replaced by a cleanup of the original targetlist). These chnages
violated some having queries executed against views so I changed
it back again. I did not have time to examine the differences between the
two versions but now it works :-)
If you want to find out, try the file queries/view_having.sql on
both versions and compare the results . Two queries won't produce a
correct result with your version.
regards
Stefan
1999-01-18 01:10:17 +01:00
|
|
|
|
2000-09-29 20:21:41 +02:00
|
|
|
parsetree->havingQual = make_and_qual(parsetree->havingQual,
|
|
|
|
copy);
|
2000-03-16 04:23:18 +01:00
|
|
|
|
|
|
|
/*
|
|
|
|
* Make sure query is marked correctly if added qual has sublinks or
|
2000-04-12 19:17:23 +02:00
|
|
|
* aggregates (not sure it can ever have aggs, but sublinks
|
|
|
|
* definitely).
|
2000-03-16 04:23:18 +01:00
|
|
|
*/
|
|
|
|
parsetree->hasAggs |= checkExprHasAggs(copy);
|
|
|
|
parsetree->hasSubLinks |= checkExprHasSubLink(copy);
|
1998-07-19 07:49:26 +02:00
|
|
|
}
|
|
|
|
|
1999-05-26 14:57:23 +02:00
|
|
|
#ifdef NOT_USED
|
Hi!
INTERSECT and EXCEPT is available for postgresql-v6.4!
The patch against v6.4 is included at the end of the current text
(in uuencoded form!)
I also included the text of my Master's Thesis. (a postscript
version). I hope that you find something of it useful and would be
happy if parts of it find their way into the PostgreSQL documentation
project (If so, tell me, then I send the sources of the document!)
The contents of the document are:
-) The first chapter might be of less interest as it gives only an
overview on SQL.
-) The second chapter gives a description on much of PostgreSQL's
features (like user defined types etc. and how to use these features)
-) The third chapter starts with an overview of PostgreSQL's internal
structure with focus on the stages a query has to pass (i.e. parser,
planner/optimizer, executor). Then a detailed description of the
implementation of the Having clause and the Intersect/Except logic is
given.
Originally I worked on v6.3.2 but never found time enough to prepare
and post a patch. Now I applied the changes to v6.4 to get Intersect
and Except working with the new version. Chapter 3 of my documentation
deals with the changes against v6.3.2, so keep that in mind when
comparing the parts of the code printed there with the patched sources
of v6.4.
Here are some remarks on the patch. There are some things that have
still to be done but at the moment I don't have time to do them
myself. (I'm doing my military service at the moment) Sorry for that
:-(
-) I used a rewrite technique for the implementation of the Except/Intersect
logic which rewrites the query to a semantically equivalent query before
it is handed to the rewrite system (for views, rules etc.), planner,
executor etc.
-) In v6.3.2 the types of the attributes of two select statements
connected by the UNION keyword had to match 100%. In v6.4 the types
only need to be familiar (i.e. int and float can be mixed). Since this
feature did not exist when I worked on Intersect/Except it
does not work correctly for Except/Intersect queries WHEN USED IN
COMBINATION WITH UNIONS! (i.e. sometimes the wrong type is used for the
resulting table. This is because until now the types of the attributes of
the first select statement have been used for the resulting table.
When Intersects and/or Excepts are used in combination with Unions it
might happen, that the first select statement of the original query
appears at another position in the query which will be executed. The reason
for this is the technique used for the implementation of
Except/Intersect which does a query rewrite!)
NOTE: It is NOT broken for pure UNION queries and pure INTERSECT/EXCEPT
queries!!!
-) I had to add the field intersect_clause to some data structures
but did not find time to implement printfuncs for the new field.
This does NOT break the debug modes but when an Except/Intersect
is used the query debug output will be the already rewritten query.
-) Massive changes to the grammar rules for SELECT and INSERT statements
have been necessary (see comments in gram.y and documentation for
deatails) in order to be able to use mixed queries like
(SELECT ... UNION (SELECT ... EXCEPT SELECT)) INTERSECT SELECT...;
-) When using UNION/EXCEPT/INTERSECT you will get:
NOTICE: equal: "Don't know if nodes of type xxx are equal".
I did not have time to add comparsion support for all the needed nodes,
but the default behaviour of the function equal met my requirements.
I did not dare to supress this message!
That's the reason why the regression test for union will fail: These
messages are also included in the union.out file!
-) Somebody of you changed the union_planner() function for v6.4
(I copied the targetlist to new_tlist and that was removed and
replaced by a cleanup of the original targetlist). These chnages
violated some having queries executed against views so I changed
it back again. I did not have time to examine the differences between the
two versions but now it works :-)
If you want to find out, try the file queries/view_having.sql on
both versions and compare the results . Two queries won't produce a
correct result with your version.
regards
Stefan
1999-01-18 01:10:17 +01:00
|
|
|
void
|
|
|
|
AddNotHavingQual(Query *parsetree, Node *havingQual)
|
|
|
|
{
|
1999-10-01 06:08:24 +02:00
|
|
|
Node *notqual;
|
Hi!
INTERSECT and EXCEPT is available for postgresql-v6.4!
The patch against v6.4 is included at the end of the current text
(in uuencoded form!)
I also included the text of my Master's Thesis. (a postscript
version). I hope that you find something of it useful and would be
happy if parts of it find their way into the PostgreSQL documentation
project (If so, tell me, then I send the sources of the document!)
The contents of the document are:
-) The first chapter might be of less interest as it gives only an
overview on SQL.
-) The second chapter gives a description on much of PostgreSQL's
features (like user defined types etc. and how to use these features)
-) The third chapter starts with an overview of PostgreSQL's internal
structure with focus on the stages a query has to pass (i.e. parser,
planner/optimizer, executor). Then a detailed description of the
implementation of the Having clause and the Intersect/Except logic is
given.
Originally I worked on v6.3.2 but never found time enough to prepare
and post a patch. Now I applied the changes to v6.4 to get Intersect
and Except working with the new version. Chapter 3 of my documentation
deals with the changes against v6.3.2, so keep that in mind when
comparing the parts of the code printed there with the patched sources
of v6.4.
Here are some remarks on the patch. There are some things that have
still to be done but at the moment I don't have time to do them
myself. (I'm doing my military service at the moment) Sorry for that
:-(
-) I used a rewrite technique for the implementation of the Except/Intersect
logic which rewrites the query to a semantically equivalent query before
it is handed to the rewrite system (for views, rules etc.), planner,
executor etc.
-) In v6.3.2 the types of the attributes of two select statements
connected by the UNION keyword had to match 100%. In v6.4 the types
only need to be familiar (i.e. int and float can be mixed). Since this
feature did not exist when I worked on Intersect/Except it
does not work correctly for Except/Intersect queries WHEN USED IN
COMBINATION WITH UNIONS! (i.e. sometimes the wrong type is used for the
resulting table. This is because until now the types of the attributes of
the first select statement have been used for the resulting table.
When Intersects and/or Excepts are used in combination with Unions it
might happen, that the first select statement of the original query
appears at another position in the query which will be executed. The reason
for this is the technique used for the implementation of
Except/Intersect which does a query rewrite!)
NOTE: It is NOT broken for pure UNION queries and pure INTERSECT/EXCEPT
queries!!!
-) I had to add the field intersect_clause to some data structures
but did not find time to implement printfuncs for the new field.
This does NOT break the debug modes but when an Except/Intersect
is used the query debug output will be the already rewritten query.
-) Massive changes to the grammar rules for SELECT and INSERT statements
have been necessary (see comments in gram.y and documentation for
deatails) in order to be able to use mixed queries like
(SELECT ... UNION (SELECT ... EXCEPT SELECT)) INTERSECT SELECT...;
-) When using UNION/EXCEPT/INTERSECT you will get:
NOTICE: equal: "Don't know if nodes of type xxx are equal".
I did not have time to add comparsion support for all the needed nodes,
but the default behaviour of the function equal met my requirements.
I did not dare to supress this message!
That's the reason why the regression test for union will fail: These
messages are also included in the union.out file!
-) Somebody of you changed the union_planner() function for v6.4
(I copied the targetlist to new_tlist and that was removed and
replaced by a cleanup of the original targetlist). These chnages
violated some having queries executed against views so I changed
it back again. I did not have time to examine the differences between the
two versions but now it works :-)
If you want to find out, try the file queries/view_having.sql on
both versions and compare the results . Two queries won't produce a
correct result with your version.
regards
Stefan
1999-01-18 01:10:17 +01:00
|
|
|
|
|
|
|
if (havingQual == NULL)
|
|
|
|
return;
|
|
|
|
|
1999-10-01 06:08:24 +02:00
|
|
|
/* Need not copy input qual, because AddHavingQual will... */
|
|
|
|
notqual = (Node *) make_notclause((Expr *) havingQual);
|
Hi!
INTERSECT and EXCEPT is available for postgresql-v6.4!
The patch against v6.4 is included at the end of the current text
(in uuencoded form!)
I also included the text of my Master's Thesis. (a postscript
version). I hope that you find something of it useful and would be
happy if parts of it find their way into the PostgreSQL documentation
project (If so, tell me, then I send the sources of the document!)
The contents of the document are:
-) The first chapter might be of less interest as it gives only an
overview on SQL.
-) The second chapter gives a description on much of PostgreSQL's
features (like user defined types etc. and how to use these features)
-) The third chapter starts with an overview of PostgreSQL's internal
structure with focus on the stages a query has to pass (i.e. parser,
planner/optimizer, executor). Then a detailed description of the
implementation of the Having clause and the Intersect/Except logic is
given.
Originally I worked on v6.3.2 but never found time enough to prepare
and post a patch. Now I applied the changes to v6.4 to get Intersect
and Except working with the new version. Chapter 3 of my documentation
deals with the changes against v6.3.2, so keep that in mind when
comparing the parts of the code printed there with the patched sources
of v6.4.
Here are some remarks on the patch. There are some things that have
still to be done but at the moment I don't have time to do them
myself. (I'm doing my military service at the moment) Sorry for that
:-(
-) I used a rewrite technique for the implementation of the Except/Intersect
logic which rewrites the query to a semantically equivalent query before
it is handed to the rewrite system (for views, rules etc.), planner,
executor etc.
-) In v6.3.2 the types of the attributes of two select statements
connected by the UNION keyword had to match 100%. In v6.4 the types
only need to be familiar (i.e. int and float can be mixed). Since this
feature did not exist when I worked on Intersect/Except it
does not work correctly for Except/Intersect queries WHEN USED IN
COMBINATION WITH UNIONS! (i.e. sometimes the wrong type is used for the
resulting table. This is because until now the types of the attributes of
the first select statement have been used for the resulting table.
When Intersects and/or Excepts are used in combination with Unions it
might happen, that the first select statement of the original query
appears at another position in the query which will be executed. The reason
for this is the technique used for the implementation of
Except/Intersect which does a query rewrite!)
NOTE: It is NOT broken for pure UNION queries and pure INTERSECT/EXCEPT
queries!!!
-) I had to add the field intersect_clause to some data structures
but did not find time to implement printfuncs for the new field.
This does NOT break the debug modes but when an Except/Intersect
is used the query debug output will be the already rewritten query.
-) Massive changes to the grammar rules for SELECT and INSERT statements
have been necessary (see comments in gram.y and documentation for
deatails) in order to be able to use mixed queries like
(SELECT ... UNION (SELECT ... EXCEPT SELECT)) INTERSECT SELECT...;
-) When using UNION/EXCEPT/INTERSECT you will get:
NOTICE: equal: "Don't know if nodes of type xxx are equal".
I did not have time to add comparsion support for all the needed nodes,
but the default behaviour of the function equal met my requirements.
I did not dare to supress this message!
That's the reason why the regression test for union will fail: These
messages are also included in the union.out file!
-) Somebody of you changed the union_planner() function for v6.4
(I copied the targetlist to new_tlist and that was removed and
replaced by a cleanup of the original targetlist). These chnages
violated some having queries executed against views so I changed
it back again. I did not have time to examine the differences between the
two versions but now it works :-)
If you want to find out, try the file queries/view_having.sql on
both versions and compare the results . Two queries won't produce a
correct result with your version.
regards
Stefan
1999-01-18 01:10:17 +01:00
|
|
|
|
1999-10-01 06:08:24 +02:00
|
|
|
AddHavingQual(parsetree, notqual);
|
Hi!
INTERSECT and EXCEPT is available for postgresql-v6.4!
The patch against v6.4 is included at the end of the current text
(in uuencoded form!)
I also included the text of my Master's Thesis. (a postscript
version). I hope that you find something of it useful and would be
happy if parts of it find their way into the PostgreSQL documentation
project (If so, tell me, then I send the sources of the document!)
The contents of the document are:
-) The first chapter might be of less interest as it gives only an
overview on SQL.
-) The second chapter gives a description on much of PostgreSQL's
features (like user defined types etc. and how to use these features)
-) The third chapter starts with an overview of PostgreSQL's internal
structure with focus on the stages a query has to pass (i.e. parser,
planner/optimizer, executor). Then a detailed description of the
implementation of the Having clause and the Intersect/Except logic is
given.
Originally I worked on v6.3.2 but never found time enough to prepare
and post a patch. Now I applied the changes to v6.4 to get Intersect
and Except working with the new version. Chapter 3 of my documentation
deals with the changes against v6.3.2, so keep that in mind when
comparing the parts of the code printed there with the patched sources
of v6.4.
Here are some remarks on the patch. There are some things that have
still to be done but at the moment I don't have time to do them
myself. (I'm doing my military service at the moment) Sorry for that
:-(
-) I used a rewrite technique for the implementation of the Except/Intersect
logic which rewrites the query to a semantically equivalent query before
it is handed to the rewrite system (for views, rules etc.), planner,
executor etc.
-) In v6.3.2 the types of the attributes of two select statements
connected by the UNION keyword had to match 100%. In v6.4 the types
only need to be familiar (i.e. int and float can be mixed). Since this
feature did not exist when I worked on Intersect/Except it
does not work correctly for Except/Intersect queries WHEN USED IN
COMBINATION WITH UNIONS! (i.e. sometimes the wrong type is used for the
resulting table. This is because until now the types of the attributes of
the first select statement have been used for the resulting table.
When Intersects and/or Excepts are used in combination with Unions it
might happen, that the first select statement of the original query
appears at another position in the query which will be executed. The reason
for this is the technique used for the implementation of
Except/Intersect which does a query rewrite!)
NOTE: It is NOT broken for pure UNION queries and pure INTERSECT/EXCEPT
queries!!!
-) I had to add the field intersect_clause to some data structures
but did not find time to implement printfuncs for the new field.
This does NOT break the debug modes but when an Except/Intersect
is used the query debug output will be the already rewritten query.
-) Massive changes to the grammar rules for SELECT and INSERT statements
have been necessary (see comments in gram.y and documentation for
deatails) in order to be able to use mixed queries like
(SELECT ... UNION (SELECT ... EXCEPT SELECT)) INTERSECT SELECT...;
-) When using UNION/EXCEPT/INTERSECT you will get:
NOTICE: equal: "Don't know if nodes of type xxx are equal".
I did not have time to add comparsion support for all the needed nodes,
but the default behaviour of the function equal met my requirements.
I did not dare to supress this message!
That's the reason why the regression test for union will fail: These
messages are also included in the union.out file!
-) Somebody of you changed the union_planner() function for v6.4
(I copied the targetlist to new_tlist and that was removed and
replaced by a cleanup of the original targetlist). These chnages
violated some having queries executed against views so I changed
it back again. I did not have time to examine the differences between the
two versions but now it works :-)
If you want to find out, try the file queries/view_having.sql on
both versions and compare the results . Two queries won't produce a
correct result with your version.
regards
Stefan
1999-01-18 01:10:17 +01:00
|
|
|
}
|
2000-04-12 19:17:23 +02:00
|
|
|
|
1999-05-26 14:57:23 +02:00
|
|
|
#endif
|
1998-07-19 07:49:26 +02:00
|
|
|
|
1996-07-09 08:22:35 +02:00
|
|
|
void
|
1997-09-08 23:56:23 +02:00
|
|
|
AddNotQual(Query *parsetree, Node *qual)
|
1996-07-09 08:22:35 +02:00
|
|
|
{
|
1999-10-01 06:08:24 +02:00
|
|
|
Node *notqual;
|
1996-07-09 08:22:35 +02:00
|
|
|
|
1997-09-07 07:04:48 +02:00
|
|
|
if (qual == NULL)
|
|
|
|
return;
|
|
|
|
|
1999-10-01 06:08:24 +02:00
|
|
|
/* Need not copy input qual, because AddQual will... */
|
|
|
|
notqual = (Node *) make_notclause((Expr *) qual);
|
1997-09-07 07:04:48 +02:00
|
|
|
|
1999-10-01 06:08:24 +02:00
|
|
|
AddQual(parsetree, notqual);
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
|
|
|
|
1999-05-12 17:02:39 +02:00
|
|
|
|
1999-10-01 06:08:24 +02:00
|
|
|
/* Find a targetlist entry by resno */
|
1997-09-08 04:41:22 +02:00
|
|
|
static Node *
|
1997-09-08 23:56:23 +02:00
|
|
|
FindMatchingNew(List *tlist, int attno)
|
1996-07-09 08:22:35 +02:00
|
|
|
{
|
1997-09-08 04:41:22 +02:00
|
|
|
List *i;
|
1996-07-09 08:22:35 +02:00
|
|
|
|
1997-09-07 07:04:48 +02:00
|
|
|
foreach(i, tlist)
|
|
|
|
{
|
1997-09-08 04:41:22 +02:00
|
|
|
TargetEntry *tle = lfirst(i);
|
1997-09-07 07:04:48 +02:00
|
|
|
|
|
|
|
if (tle->resdom->resno == attno)
|
1998-09-01 05:29:17 +02:00
|
|
|
return tle->expr;
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
1997-09-07 07:04:48 +02:00
|
|
|
return NULL;
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
|
|
|
|
2000-09-29 20:21:41 +02:00
|
|
|
#ifdef NOT_USED
|
|
|
|
|
1999-10-01 06:08:24 +02:00
|
|
|
/* Find a targetlist entry by resname */
|
1997-09-08 04:41:22 +02:00
|
|
|
static Node *
|
1997-09-08 23:56:23 +02:00
|
|
|
FindMatchingTLEntry(List *tlist, char *e_attname)
|
1996-07-09 08:22:35 +02:00
|
|
|
{
|
1997-09-08 04:41:22 +02:00
|
|
|
List *i;
|
1997-09-07 07:04:48 +02:00
|
|
|
|
|
|
|
foreach(i, tlist)
|
|
|
|
{
|
1997-09-08 04:41:22 +02:00
|
|
|
TargetEntry *tle = lfirst(i);
|
|
|
|
char *resname;
|
1997-09-07 07:04:48 +02:00
|
|
|
|
|
|
|
resname = tle->resdom->resname;
|
2000-09-29 20:21:41 +02:00
|
|
|
if (strcmp(e_attname, resname) == 0)
|
1998-09-01 05:29:17 +02:00
|
|
|
return tle->expr;
|
1997-09-07 07:04:48 +02:00
|
|
|
}
|
|
|
|
return NULL;
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
|
|
|
|
2000-09-29 20:21:41 +02:00
|
|
|
#endif
|
|
|
|
|
1998-01-21 05:24:46 +01:00
|
|
|
|
1999-10-01 06:08:24 +02:00
|
|
|
/*
|
|
|
|
* ResolveNew - replace Vars with corresponding items from a targetlist
|
|
|
|
*
|
2000-09-29 20:21:41 +02:00
|
|
|
* Vars matching target_varno and sublevels_up are replaced by the
|
1999-10-01 06:08:24 +02:00
|
|
|
* entry with matching resno from targetlist, if there is one.
|
2000-09-29 20:21:41 +02:00
|
|
|
* If not, we either change the unmatched Var's varno to update_varno
|
|
|
|
* (when event == CMD_UPDATE) or replace it with a constant NULL.
|
1999-10-01 06:08:24 +02:00
|
|
|
*/
|
1996-07-09 08:22:35 +02:00
|
|
|
|
2000-04-12 19:17:23 +02:00
|
|
|
typedef struct
|
|
|
|
{
|
2000-09-29 20:21:41 +02:00
|
|
|
int target_varno;
|
2000-04-12 19:17:23 +02:00
|
|
|
int sublevels_up;
|
2000-09-29 20:21:41 +02:00
|
|
|
List *targetlist;
|
|
|
|
int event;
|
|
|
|
int update_varno;
|
1999-10-01 06:08:24 +02:00
|
|
|
} ResolveNew_context;
|
1996-07-09 08:22:35 +02:00
|
|
|
|
1999-10-01 06:08:24 +02:00
|
|
|
static Node *
|
|
|
|
ResolveNew_mutator(Node *node, ResolveNew_context *context)
|
1996-07-09 08:22:35 +02:00
|
|
|
{
|
1997-09-07 07:04:48 +02:00
|
|
|
if (node == NULL)
|
1999-10-01 06:08:24 +02:00
|
|
|
return NULL;
|
|
|
|
if (IsA(node, Var))
|
1996-07-09 08:22:35 +02:00
|
|
|
{
|
1999-10-01 06:08:24 +02:00
|
|
|
Var *var = (Var *) node;
|
|
|
|
int this_varno = (int) var->varno;
|
|
|
|
int this_varlevelsup = (int) var->varlevelsup;
|
1998-01-04 05:31:43 +01:00
|
|
|
|
2000-09-29 20:21:41 +02:00
|
|
|
if (this_varno == context->target_varno &&
|
1999-10-01 06:08:24 +02:00
|
|
|
this_varlevelsup == context->sublevels_up)
|
|
|
|
{
|
2001-04-18 22:42:56 +02:00
|
|
|
Node *n;
|
|
|
|
|
|
|
|
/* band-aid: don't do the wrong thing with a whole-tuple Var */
|
|
|
|
if (var->varattno == InvalidAttrNumber)
|
|
|
|
elog(ERROR, "ResolveNew: can't handle whole-tuple reference");
|
|
|
|
|
|
|
|
n = FindMatchingNew(context->targetlist, var->varattno);
|
1998-10-02 18:28:04 +02:00
|
|
|
|
1999-10-01 06:08:24 +02:00
|
|
|
if (n == NULL)
|
1997-09-07 07:04:48 +02:00
|
|
|
{
|
2000-09-29 20:21:41 +02:00
|
|
|
if (context->event == CMD_UPDATE)
|
1997-09-07 07:04:48 +02:00
|
|
|
{
|
1999-10-01 06:08:24 +02:00
|
|
|
/* For update, just change unmatched var's varno */
|
2000-09-29 20:21:41 +02:00
|
|
|
var = (Var *) copyObject(node);
|
|
|
|
var->varno = context->update_varno;
|
|
|
|
var->varnoold = context->update_varno;
|
|
|
|
return (Node *) var;
|
1999-10-01 06:08:24 +02:00
|
|
|
}
|
|
|
|
else
|
|
|
|
{
|
|
|
|
/* Otherwise replace unmatched var with a null */
|
2000-11-16 23:30:52 +01:00
|
|
|
return (Node *) makeNullConst(var->vartype);
|
1997-09-07 07:04:48 +02:00
|
|
|
}
|
1998-01-21 05:24:46 +01:00
|
|
|
}
|
1999-10-01 06:08:24 +02:00
|
|
|
else
|
1998-01-21 05:24:46 +01:00
|
|
|
{
|
1999-10-01 06:08:24 +02:00
|
|
|
/* Make a copy of the tlist item to return */
|
|
|
|
n = copyObject(n);
|
2000-03-16 04:23:18 +01:00
|
|
|
/* Adjust varlevelsup if tlist item is from higher query */
|
|
|
|
if (this_varlevelsup > 0)
|
|
|
|
IncrementVarSublevelsUp(n, this_varlevelsup, 0);
|
1999-10-01 06:08:24 +02:00
|
|
|
return n;
|
1997-09-07 07:04:48 +02:00
|
|
|
}
|
1999-10-01 06:08:24 +02:00
|
|
|
}
|
|
|
|
/* otherwise fall through to copy the var normally */
|
|
|
|
}
|
2000-04-12 19:17:23 +02:00
|
|
|
|
1999-10-01 06:08:24 +02:00
|
|
|
/*
|
|
|
|
* Since expression_tree_mutator won't touch subselects, we have to
|
|
|
|
* handle them specially.
|
|
|
|
*/
|
|
|
|
if (IsA(node, SubLink))
|
|
|
|
{
|
2000-04-12 19:17:23 +02:00
|
|
|
SubLink *sublink = (SubLink *) node;
|
|
|
|
SubLink *newnode;
|
1999-10-01 06:08:24 +02:00
|
|
|
|
|
|
|
FLATCOPY(newnode, sublink, SubLink);
|
|
|
|
MUTATE(newnode->lefthand, sublink->lefthand, List *,
|
|
|
|
ResolveNew_mutator, context);
|
|
|
|
MUTATE(newnode->subselect, sublink->subselect, Node *,
|
|
|
|
ResolveNew_mutator, context);
|
|
|
|
return (Node *) newnode;
|
|
|
|
}
|
|
|
|
if (IsA(node, Query))
|
|
|
|
{
|
2000-04-12 19:17:23 +02:00
|
|
|
Query *query = (Query *) node;
|
|
|
|
Query *newnode;
|
1998-01-21 05:24:46 +01:00
|
|
|
|
1999-10-01 06:08:24 +02:00
|
|
|
FLATCOPY(newnode, query, Query);
|
2000-10-05 21:11:39 +02:00
|
|
|
context->sublevels_up++;
|
|
|
|
query_tree_mutator(newnode, ResolveNew_mutator, context, true);
|
|
|
|
context->sublevels_up--;
|
1999-10-01 06:08:24 +02:00
|
|
|
return (Node *) newnode;
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
1999-10-01 06:08:24 +02:00
|
|
|
return expression_tree_mutator(node, ResolveNew_mutator,
|
|
|
|
(void *) context);
|
|
|
|
}
|
|
|
|
|
2000-09-29 20:21:41 +02:00
|
|
|
Node *
|
|
|
|
ResolveNew(Node *node, int target_varno, int sublevels_up,
|
|
|
|
List *targetlist, int event, int update_varno)
|
1999-10-01 06:08:24 +02:00
|
|
|
{
|
2000-04-12 19:17:23 +02:00
|
|
|
ResolveNew_context context;
|
1999-10-01 06:08:24 +02:00
|
|
|
|
2000-09-29 20:21:41 +02:00
|
|
|
context.target_varno = target_varno;
|
1999-10-01 06:08:24 +02:00
|
|
|
context.sublevels_up = sublevels_up;
|
2000-09-29 20:21:41 +02:00
|
|
|
context.targetlist = targetlist;
|
|
|
|
context.event = event;
|
|
|
|
context.update_varno = update_varno;
|
1999-10-01 06:08:24 +02:00
|
|
|
|
2000-09-29 20:21:41 +02:00
|
|
|
/*
|
2000-10-05 21:11:39 +02:00
|
|
|
* Must be prepared to start with a Query or a bare expression tree;
|
2001-03-22 05:01:46 +01:00
|
|
|
* if it's a Query, go straight to query_tree_mutator to make sure
|
|
|
|
* that sublevels_up doesn't get incremented prematurely.
|
2000-09-29 20:21:41 +02:00
|
|
|
*/
|
2000-10-05 21:11:39 +02:00
|
|
|
if (node && IsA(node, Query))
|
|
|
|
{
|
|
|
|
Query *query = (Query *) node;
|
|
|
|
Query *newnode;
|
|
|
|
|
|
|
|
FLATCOPY(newnode, query, Query);
|
|
|
|
query_tree_mutator(newnode, ResolveNew_mutator,
|
|
|
|
(void *) &context, true);
|
|
|
|
return (Node *) newnode;
|
|
|
|
}
|
|
|
|
else
|
|
|
|
return ResolveNew_mutator(node, &context);
|
1999-10-01 06:08:24 +02:00
|
|
|
}
|
|
|
|
|
2000-09-29 20:21:41 +02:00
|
|
|
|
|
|
|
#ifdef NOT_USED
|
|
|
|
|
1997-09-07 07:04:48 +02:00
|
|
|
/*
|
1999-10-01 06:08:24 +02:00
|
|
|
* HandleRIRAttributeRule
|
|
|
|
* Replace Vars matching a given RT index with copies of TL expressions.
|
|
|
|
*
|
1996-07-09 08:22:35 +02:00
|
|
|
* Handles 'on retrieve to relation.attribute
|
1997-09-07 07:04:48 +02:00
|
|
|
* do instead retrieve (attribute = expression) w/qual'
|
1996-07-09 08:22:35 +02:00
|
|
|
*/
|
1998-02-26 05:46:47 +01:00
|
|
|
|
2000-04-12 19:17:23 +02:00
|
|
|
typedef struct
|
|
|
|
{
|
|
|
|
List *rtable;
|
|
|
|
List *targetlist;
|
|
|
|
int rt_index;
|
|
|
|
int attr_num;
|
|
|
|
int *modified;
|
|
|
|
int *badsql;
|
|
|
|
int sublevels_up;
|
2001-03-22 05:01:46 +01:00
|
|
|
} HandleRIRAttributeRule_context;
|
1996-07-09 08:22:35 +02:00
|
|
|
|
1999-10-01 06:08:24 +02:00
|
|
|
static Node *
|
|
|
|
HandleRIRAttributeRule_mutator(Node *node,
|
2001-03-22 05:01:46 +01:00
|
|
|
HandleRIRAttributeRule_context * context)
|
1996-07-09 08:22:35 +02:00
|
|
|
{
|
1997-09-07 07:04:48 +02:00
|
|
|
if (node == NULL)
|
1999-10-01 06:08:24 +02:00
|
|
|
return NULL;
|
|
|
|
if (IsA(node, Var))
|
1996-07-09 08:22:35 +02:00
|
|
|
{
|
1999-10-01 06:08:24 +02:00
|
|
|
Var *var = (Var *) node;
|
|
|
|
int this_varno = var->varno;
|
|
|
|
int this_varattno = var->varattno;
|
|
|
|
int this_varlevelsup = var->varlevelsup;
|
|
|
|
|
|
|
|
if (this_varno == context->rt_index &&
|
|
|
|
this_varattno == context->attr_num &&
|
|
|
|
this_varlevelsup == context->sublevels_up)
|
|
|
|
{
|
|
|
|
if (var->vartype == 32)
|
|
|
|
{ /* HACK: disallow SET variables */
|
|
|
|
*context->modified = TRUE;
|
|
|
|
*context->badsql = TRUE;
|
2000-11-16 23:30:52 +01:00
|
|
|
return (Node *) makeNullConst(var->vartype);
|
1999-10-01 06:08:24 +02:00
|
|
|
}
|
|
|
|
else
|
|
|
|
{
|
2000-04-12 19:17:23 +02:00
|
|
|
char *name_to_look_for;
|
2000-03-16 04:23:18 +01:00
|
|
|
|
|
|
|
name_to_look_for = get_attname(getrelid(this_varno,
|
|
|
|
context->rtable),
|
|
|
|
this_varattno);
|
|
|
|
if (name_to_look_for)
|
1998-09-01 06:40:42 +02:00
|
|
|
{
|
1999-10-01 06:08:24 +02:00
|
|
|
Node *n;
|
|
|
|
|
|
|
|
*context->modified = TRUE;
|
|
|
|
n = FindMatchingTLEntry(context->targetlist,
|
2000-03-16 04:23:18 +01:00
|
|
|
name_to_look_for);
|
1998-09-01 06:40:42 +02:00
|
|
|
if (n == NULL)
|
2000-11-16 23:30:52 +01:00
|
|
|
return (Node *) makeNullConst(var->vartype);
|
2000-03-16 04:23:18 +01:00
|
|
|
/* Make a copy of the tlist item to return */
|
|
|
|
n = copyObject(n);
|
2000-04-12 19:17:23 +02:00
|
|
|
|
|
|
|
/*
|
|
|
|
* Adjust varlevelsup if tlist item is from higher
|
|
|
|
* query
|
|
|
|
*/
|
2000-03-16 04:23:18 +01:00
|
|
|
if (this_varlevelsup > 0)
|
|
|
|
IncrementVarSublevelsUp(n, this_varlevelsup, 0);
|
|
|
|
return n;
|
1998-01-21 05:24:46 +01:00
|
|
|
}
|
|
|
|
}
|
1999-10-01 06:08:24 +02:00
|
|
|
}
|
|
|
|
/* otherwise fall through to copy the var normally */
|
|
|
|
}
|
2000-04-12 19:17:23 +02:00
|
|
|
|
1999-10-01 06:08:24 +02:00
|
|
|
/*
|
|
|
|
* Since expression_tree_mutator won't touch subselects, we have to
|
|
|
|
* handle them specially.
|
|
|
|
*/
|
|
|
|
if (IsA(node, SubLink))
|
|
|
|
{
|
2000-04-12 19:17:23 +02:00
|
|
|
SubLink *sublink = (SubLink *) node;
|
|
|
|
SubLink *newnode;
|
1999-10-01 06:08:24 +02:00
|
|
|
|
|
|
|
FLATCOPY(newnode, sublink, SubLink);
|
|
|
|
MUTATE(newnode->lefthand, sublink->lefthand, List *,
|
|
|
|
HandleRIRAttributeRule_mutator, context);
|
|
|
|
MUTATE(newnode->subselect, sublink->subselect, Node *,
|
|
|
|
HandleRIRAttributeRule_mutator, context);
|
|
|
|
return (Node *) newnode;
|
|
|
|
}
|
|
|
|
if (IsA(node, Query))
|
|
|
|
{
|
2000-04-12 19:17:23 +02:00
|
|
|
Query *query = (Query *) node;
|
|
|
|
Query *newnode;
|
Hi!
INTERSECT and EXCEPT is available for postgresql-v6.4!
The patch against v6.4 is included at the end of the current text
(in uuencoded form!)
I also included the text of my Master's Thesis. (a postscript
version). I hope that you find something of it useful and would be
happy if parts of it find their way into the PostgreSQL documentation
project (If so, tell me, then I send the sources of the document!)
The contents of the document are:
-) The first chapter might be of less interest as it gives only an
overview on SQL.
-) The second chapter gives a description on much of PostgreSQL's
features (like user defined types etc. and how to use these features)
-) The third chapter starts with an overview of PostgreSQL's internal
structure with focus on the stages a query has to pass (i.e. parser,
planner/optimizer, executor). Then a detailed description of the
implementation of the Having clause and the Intersect/Except logic is
given.
Originally I worked on v6.3.2 but never found time enough to prepare
and post a patch. Now I applied the changes to v6.4 to get Intersect
and Except working with the new version. Chapter 3 of my documentation
deals with the changes against v6.3.2, so keep that in mind when
comparing the parts of the code printed there with the patched sources
of v6.4.
Here are some remarks on the patch. There are some things that have
still to be done but at the moment I don't have time to do them
myself. (I'm doing my military service at the moment) Sorry for that
:-(
-) I used a rewrite technique for the implementation of the Except/Intersect
logic which rewrites the query to a semantically equivalent query before
it is handed to the rewrite system (for views, rules etc.), planner,
executor etc.
-) In v6.3.2 the types of the attributes of two select statements
connected by the UNION keyword had to match 100%. In v6.4 the types
only need to be familiar (i.e. int and float can be mixed). Since this
feature did not exist when I worked on Intersect/Except it
does not work correctly for Except/Intersect queries WHEN USED IN
COMBINATION WITH UNIONS! (i.e. sometimes the wrong type is used for the
resulting table. This is because until now the types of the attributes of
the first select statement have been used for the resulting table.
When Intersects and/or Excepts are used in combination with Unions it
might happen, that the first select statement of the original query
appears at another position in the query which will be executed. The reason
for this is the technique used for the implementation of
Except/Intersect which does a query rewrite!)
NOTE: It is NOT broken for pure UNION queries and pure INTERSECT/EXCEPT
queries!!!
-) I had to add the field intersect_clause to some data structures
but did not find time to implement printfuncs for the new field.
This does NOT break the debug modes but when an Except/Intersect
is used the query debug output will be the already rewritten query.
-) Massive changes to the grammar rules for SELECT and INSERT statements
have been necessary (see comments in gram.y and documentation for
deatails) in order to be able to use mixed queries like
(SELECT ... UNION (SELECT ... EXCEPT SELECT)) INTERSECT SELECT...;
-) When using UNION/EXCEPT/INTERSECT you will get:
NOTICE: equal: "Don't know if nodes of type xxx are equal".
I did not have time to add comparsion support for all the needed nodes,
but the default behaviour of the function equal met my requirements.
I did not dare to supress this message!
That's the reason why the regression test for union will fail: These
messages are also included in the union.out file!
-) Somebody of you changed the union_planner() function for v6.4
(I copied the targetlist to new_tlist and that was removed and
replaced by a cleanup of the original targetlist). These chnages
violated some having queries executed against views so I changed
it back again. I did not have time to examine the differences between the
two versions but now it works :-)
If you want to find out, try the file queries/view_having.sql on
both versions and compare the results . Two queries won't produce a
correct result with your version.
regards
Stefan
1999-01-18 01:10:17 +01:00
|
|
|
|
1999-10-01 06:08:24 +02:00
|
|
|
FLATCOPY(newnode, query, Query);
|
2000-10-05 21:11:39 +02:00
|
|
|
context->sublevels_up++;
|
|
|
|
query_tree_mutator(newnode, HandleRIRAttributeRule_mutator,
|
|
|
|
context, true);
|
|
|
|
context->sublevels_up--;
|
1999-10-01 06:08:24 +02:00
|
|
|
return (Node *) newnode;
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
1999-10-01 06:08:24 +02:00
|
|
|
return expression_tree_mutator(node, HandleRIRAttributeRule_mutator,
|
|
|
|
(void *) context);
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
void
|
1999-10-01 06:08:24 +02:00
|
|
|
HandleRIRAttributeRule(Query *parsetree,
|
|
|
|
List *rtable,
|
|
|
|
List *targetlist,
|
|
|
|
int rt_index,
|
|
|
|
int attr_num,
|
|
|
|
int *modified,
|
|
|
|
int *badsql)
|
1996-07-09 08:22:35 +02:00
|
|
|
{
|
2000-04-12 19:17:23 +02:00
|
|
|
HandleRIRAttributeRule_context context;
|
1999-10-01 06:08:24 +02:00
|
|
|
|
|
|
|
context.rtable = rtable;
|
|
|
|
context.targetlist = targetlist;
|
|
|
|
context.rt_index = rt_index;
|
|
|
|
context.attr_num = attr_num;
|
|
|
|
context.modified = modified;
|
|
|
|
context.badsql = badsql;
|
|
|
|
context.sublevels_up = 0;
|
|
|
|
|
2000-10-05 21:11:39 +02:00
|
|
|
query_tree_mutator(parsetree, HandleRIRAttributeRule_mutator,
|
|
|
|
(void *) &context, true);
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
2000-09-29 20:21:41 +02:00
|
|
|
|
2001-03-22 05:01:46 +01:00
|
|
|
#endif /* NOT_USED */
|