1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
|
/*-------------------------------------------------------------------------
*
* joininfo.c
* JoinInfo node manipulation routines
*
* Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/util/joininfo.c,v 1.19 1999/02/22 05:26:26 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "nodes/relation.h"
#include "optimizer/internal.h"
#include "optimizer/joininfo.h"
#include "optimizer/var.h"
#include "optimizer/clauses.h"
/*
* joininfo_member
* Determines whether a node has already been created for a join
* between a set of join relations and the relation described by
* 'joininfo_list'.
*
* 'join_relids' is a list of relids corresponding to the join relation
* 'joininfo_list' is the list of joininfo nodes against which this is
* checked
*
* Returns the corresponding node in 'joininfo_list' if such a node
* exists.
*
*/
JoinInfo *
joininfo_member(List *join_relids, List *joininfo_list)
{
List *i;
foreach(i, joininfo_list)
{
JoinInfo *joininfo = (JoinInfo *)lfirst(i);
if (same(join_relids, joininfo->unjoined_relids))
return joininfo;
}
return NULL;
}
/*
* find_joininfo_node
* Find the joininfo node within a relation entry corresponding
* to a join between 'this_rel' and the relations in 'join_relids'. A
* new node is created and added to the relation entry's joininfo
* field if the desired one can't be found.
*
* Returns a joininfo node.
*
*/
JoinInfo *
find_joininfo_node(RelOptInfo *this_rel, Relids join_relids)
{
JoinInfo *joininfo = joininfo_member(join_relids,
this_rel->joininfo);
if (joininfo == NULL)
{
joininfo = makeNode(JoinInfo);
joininfo->unjoined_relids = join_relids;
joininfo->jinfo_restrictinfo = NIL;
joininfo->mergejoinable = false;
joininfo->hashjoinable = false;
this_rel->joininfo = lcons(joininfo, this_rel->joininfo);
}
return joininfo;
}
/*
* other_join_clause_var
* Determines whether a var node is contained within a joinclause
* of the form(op var var).
*
* Returns the other var node in the joinclause if it is, nil if not.
*
*/
Var *
other_join_clause_var(Var *var, Expr *clause)
{
Var *retval;
Var *l,
*r;
retval = (Var *) NULL;
if (var != NULL && is_joinable((Node *) clause))
{
l = (Var *) get_leftop(clause);
r = (Var *) get_rightop(clause);
if (equal(var, l))
retval = r;
else if (equal(var, r))
retval = l;
}
return retval;
}
|
