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Commit389af07

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Clean up rewriter routines to use expression_tree_walker and
expression_tree_mutator rather than ad-hoc tree walking code. This shortensthe code materially and fixes a fair number of sins of omission. Also,change modifyAggrefQual to *not* recurse into subselects, since its missionis satisfied if it removes aggregate functions from the top level of aWHERE clause. This cures problems with queries of the form SELECT ...WHERE x IN (SELECT ... HAVING something-using-an-aggregate), which wouldformerly get mucked up by modifyAggrefQual. The routine is stillfundamentally broken, of course, but I don't think there's any way to getrid of it before we implement subselects in FROM ...
1 parentce1f5ed commit389af07

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4 files changed

+979
-2457
lines changed

4 files changed

+979
-2457
lines changed

‎src/backend/rewrite/locks.c‎

Lines changed: 61 additions & 76 deletions
Original file line numberDiff line numberDiff line change
@@ -6,14 +6,15 @@
66
*
77
*
88
* IDENTIFICATION
9-
* $Header: /cvsroot/pgsql/src/backend/rewrite/Attic/locks.c,v 1.22 1999/09/18 19:07:18 tgl Exp $
9+
* $Header: /cvsroot/pgsql/src/backend/rewrite/Attic/locks.c,v 1.23 1999/10/01 04:08:24 tgl Exp $
1010
*
1111
*-------------------------------------------------------------------------
1212
*/
1313
#include"postgres.h"
1414

1515
#include"access/heapam.h"
1616
#include"catalog/pg_shadow.h"
17+
#include"optimizer/clauses.h"
1718
#include"rewrite/locks.h"
1819
#include"utils/acl.h"
1920
#include"utils/builtins.h"
@@ -22,102 +23,86 @@
2223

2324

2425
/*
25-
*ThisLockWasTriggered
26+
*thisLockWasTriggered
2627
*
2728
* walk the tree, if there we find a varnode,
2829
* we check the varattno against the attnum
2930
* if we find at least one such match, we return true
3031
* otherwise, we return false
32+
*
33+
* XXX this should be unified with attribute_used()
3134
*/
35+
36+
typedefstruct {
37+
intvarno;
38+
intattnum;
39+
intsublevels_up;
40+
}thisLockWasTriggered_context;
41+
3242
staticbool
33-
nodeThisLockWasTriggered(Node*node,intvarno,AttrNumberattnum,
34-
intsublevels_up)
43+
thisLockWasTriggered_walker(Node*node,
44+
thisLockWasTriggered_context*context)
3545
{
3646
if (node==NULL)
37-
returnFALSE;
38-
switch (nodeTag(node))
47+
returnfalse;
48+
if (IsA(node,Var))
3949
{
40-
caseT_Var:
41-
{
42-
Var*var= (Var*)node;
50+
Var*var= (Var*)node;
4351

44-
if (varno==var->varno&&
45-
(attnum==var->varattno||attnum==-1))
46-
return TRUE;
47-
}
48-
break;
49-
caseT_Expr:
50-
{
51-
Expr*expr= (Expr*)node;
52-
53-
returnnodeThisLockWasTriggered((Node*)expr->args,varno,
54-
attnum,sublevels_up);
55-
}
56-
break;
57-
caseT_TargetEntry:
58-
{
59-
TargetEntry*tle= (TargetEntry*)node;
60-
61-
returnnodeThisLockWasTriggered(tle->expr,varno,attnum,
62-
sublevels_up);
63-
}
64-
break;
65-
caseT_Aggref:
66-
{
67-
Aggref*aggref= (Aggref*)node;
68-
69-
returnnodeThisLockWasTriggered(aggref->target,varno,attnum,
70-
sublevels_up);
71-
}
72-
break;
73-
caseT_List:
74-
{
75-
List*l;
76-
77-
foreach(l, (List*)node)
78-
{
79-
if (nodeThisLockWasTriggered(lfirst(l),varno,attnum,
80-
sublevels_up))
81-
return TRUE;
82-
}
83-
return FALSE;
84-
}
85-
break;
86-
caseT_SubLink:
87-
{
88-
SubLink*sublink= (SubLink*)node;
89-
Query*query= (Query*)sublink->subselect;
52+
if (var->varlevelsup==context->sublevels_up&&
53+
var->varno==context->varno&&
54+
(var->varattno==context->attnum||context->attnum==-1))
55+
return true;
56+
return false;
57+
}
58+
if (IsA(node,SubLink))
59+
{
60+
/*
61+
* Standard expression_tree_walker will not recurse into subselect,
62+
* but here we must do so.
63+
*/
64+
SubLink*sub= (SubLink*)node;
9065

91-
returnnodeThisLockWasTriggered(query->qual,varno,attnum,
92-
sublevels_up+1);
93-
}
94-
break;
95-
default:
96-
break;
66+
if (thisLockWasTriggered_walker((Node*) (sub->lefthand),context))
67+
return true;
68+
context->sublevels_up++;
69+
if (thisLockWasTriggered_walker((Node*) (sub->subselect),context))
70+
{
71+
context->sublevels_up--;/* not really necessary */
72+
return true;
73+
}
74+
context->sublevels_up--;
75+
return false;
76+
}
77+
if (IsA(node,Query))
78+
{
79+
/* Reach here after recursing down into subselect above... */
80+
Query*qry= (Query*)node;
81+
82+
if (thisLockWasTriggered_walker((Node*) (qry->targetList),context))
83+
return true;
84+
if (thisLockWasTriggered_walker((Node*) (qry->qual),context))
85+
return true;
86+
if (thisLockWasTriggered_walker((Node*) (qry->havingQual),context))
87+
return true;
88+
return false;
9789
}
98-
return FALSE;
90+
returnexpression_tree_walker(node,thisLockWasTriggered_walker,
91+
(void*)context);
9992
}
10093

101-
/*
102-
* thisLockWasTriggered -
103-
* walk the tree, if there we find a varnode, we check the varattno
104-
* against the attnum if we find at least one such match, we return true
105-
* otherwise, we return false
106-
*/
10794
staticbool
10895
thisLockWasTriggered(intvarno,
109-
AttrNumberattnum,
96+
intattnum,
11097
Query*parsetree)
11198
{
99+
thisLockWasTriggered_contextcontext;
112100

113-
if (nodeThisLockWasTriggered(parsetree->qual,varno,attnum,0))
114-
return true;
115-
116-
if (nodeThisLockWasTriggered((Node*)parsetree->targetList,varno,attnum,0))
117-
return true;
118-
119-
return false;
101+
context.varno=varno;
102+
context.attnum=attnum;
103+
context.sublevels_up=0;
120104

105+
returnthisLockWasTriggered_walker((Node*)parsetree,&context);
121106
}
122107

123108
/*

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