Drizzled Public API Documentation

position.h
1 /* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
2  * vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
3  *
4  * Copyright (C) 2009 Sun Microsystems, Inc.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; version 2 of the License.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, write to the Free Software
17  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18  */
19 
20 #pragma once
21 
22 #include <drizzled/join_table.h>
23 
24 namespace drizzled
25 {
26 namespace optimizer
27 {
28 
33 class Position
34 {
35 public:
36 
37  Position()
38  :
39  records_read(0),
40  read_time(0),
41  table(NULL),
42  key(NULL),
44  {}
45 
46  Position(double in_records_read,
47  double in_read_time,
48  JoinTable *in_table,
49  KeyUse *in_key,
50  table_map in_ref_depend_map)
51  :
52  records_read(in_records_read),
53  read_time(in_read_time),
54  table(in_table),
55  key(in_key),
56  ref_depend_map(in_ref_depend_map)
57  {}
58 
59  Position(const Position &rhs)
60  :
62  read_time(rhs.read_time),
63  table(rhs.table),
64  key(rhs.key),
66  {}
67 
68  Position &operator=(const Position &rhs)
69  {
70  if (this == &rhs)
71  {
72  return *this;
73  }
75  read_time= rhs.read_time;
76  table= rhs.table;
77  key= rhs.key;
79  return *this;
80  }
81 
96  bool isConstTable() const
97  {
98  return (records_read < 2.0);
99  }
100 
101  double getFanout() const
102  {
103  return records_read;
104  }
105 
106  void setFanout(double in_records_read)
107  {
108  records_read= in_records_read;
109  }
110 
111  double getCost() const
112  {
113  return read_time;
114  }
115 
116  JoinTable *getJoinTable()
117  {
118  return table;
119  }
120 
128  bool hasTableForSorting(Table *cmp_table) const
129  {
130  return (cmp_table != table->table);
131  }
132 
133  bool examinePosition(table_map found_ref);
134 
135  KeyUse *getKeyUse()
136  {
137  return key;
138  }
139 
140  table_map getRefDependMap() const
141  {
142  return ref_depend_map;
143  }
144 
145  void clearRefDependMap()
146  {
147  ref_depend_map= 0;
148  }
149 
150 private:
151 
157  double records_read;
158 
164  double read_time;
165 
166  JoinTable *table;
167 
173 
175  table_map ref_depend_map;
176 
177 };
178 
179 } /* end namespace optimizer */
180 
181 } /* end namespace drizzled */
182 
TODO: Rename this file - func.h is stupid.
bool isConstTable() const
Definition: position.h:96
bool hasTableForSorting(Table *cmp_table) const
Definition: position.h:128