Drizzled Public API Documentation
Main Page
Related Pages
Modules
Namespaces
Classes
Files
File List
File Members
sel_imerge.h
1
/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
2
* vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
3
*
4
* Copyright (C) 2008-2009 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/memory/sql_alloc.h>
23
24
namespace
drizzled {
25
namespace
optimizer {
26
27
/*
28
SEL_IMERGE is a list of possible ways to do index merge, i.e. it is
29
a condition in the following form:
30
(t_1||t_2||...||t_N) && (next)
31
32
where all t_i are optimizer::SEL_TREEs, next is another SEL_IMERGE and no pair
33
(t_i,t_j) contains SEL_ARGS for the same index.
34
35
optimizer::SEL_TREE contained in SEL_IMERGE always has merges=NULL.
36
37
This class relies on memory manager to do the cleanup.
38
*/
39
class
SEL_IMERGE
:
public
memory::SqlAlloc
40
{
41
enum
{ PREALLOCED_TREES= 10};
42
public
:
43
SEL_TREE
*trees_prealloced[PREALLOCED_TREES];
44
SEL_TREE
**trees;
/* trees used to do index_merge */
45
SEL_TREE
**trees_next;
/* last of these trees */
46
SEL_TREE
**trees_end;
/* end of allocated space */
47
48
SEL_ARG
***best_keys;
/* best keys to read in optimizer::SEL_TREEs */
49
50
SEL_IMERGE
();
51
52
/*
53
Add optimizer::SEL_TREE to this index_merge without any checks,
54
55
NOTES
56
This function implements the following:
57
(x_1||...||x_N) || t = (x_1||...||x_N||t), where x_i, t are optimizer::SEL_TREEs
58
59
RETURN
60
0 - OK
61
-1 - Out of memory.
62
*/
63
void
or_sel_tree(
RangeParameter
*param,
SEL_TREE
*tree);
64
65
/*
66
Perform OR operation on this SEL_IMERGE and supplied optimizer::SEL_TREE new_tree,
67
combining new_tree with one of the trees in this SEL_IMERGE if they both
68
have SEL_ARGs for the same key.
69
70
SYNOPSIS
71
or_sel_tree_with_checks()
72
param Parameter from SqlSelect::test_quick_select
73
new_tree optimizer::SEL_TREE with type KEY or KEY_SMALLER.
74
75
NOTES
76
This does the following:
77
(t_1||...||t_k)||new_tree =
78
either
79
= (t_1||...||t_k||new_tree)
80
or
81
= (t_1||....||(t_j|| new_tree)||...||t_k),
82
83
where t_i, y are optimizer::SEL_TREEs.
84
new_tree is combined with the first t_j it has a SEL_ARG on common
85
key with. As a consequence of this, choice of keys to do index_merge
86
read may depend on the order of conditions in WHERE part of the query.
87
88
RETURN
89
0 OK
90
1 One of the trees was combined with new_tree to optimizer::SEL_TREE::ALWAYS,
91
and (*this) should be discarded.
92
-1 An error occurred.
93
*/
94
int
or_sel_tree_with_checks(
RangeParameter
&,
SEL_TREE
&);
95
96
/*
97
Perform OR operation on this index_merge and supplied index_merge list.
98
99
RETURN
100
0 - OK
101
1 - One of conditions in result is always true and this SEL_IMERGE
102
should be discarded.
103
-1 - An error occurred
104
*/
105
int
or_sel_imerge_with_checks(
RangeParameter
&,
SEL_IMERGE
&);
106
107
};
108
109
110
}
/* namespace optimizer */
111
112
}
/* namespace drizzled */
113
drizzled::memory::SqlAlloc
Definition:
sql_alloc.h:34
drizzled::optimizer::SEL_ARG
Definition:
sel_arg.h:195
drizzled::optimizer::SEL_IMERGE
Definition:
sel_imerge.h:39
drizzled::optimizer::SEL_TREE
Definition:
sel_tree.h:27
drizzled::optimizer::RangeParameter
Definition:
range_param.h:80
drizzled
optimizer
sel_imerge.h
Generated on Fri May 23 2014 13:09:14 for drizzle by
1.8.7