« back to all changes in this revision
Viewing changes to drizzled/optimizer/quick_range_select.h
- browse files at revision 1237.13.5
- compare with another revision
- compare with revision 1237.13.5
- download diff
- download tarball
- view history from revision 1237.13.5
- Committer: Padraig O'Sullivan
- Date: 2009-12-07 21:50:09 UTC
- mto: (1192.3.76 pandora-build) (1240.3.1 build) (1241.2.6 build)
- mto: This revision was merged to the branch mainline in revision 1241.
- Revision ID: osullivan.padraig@gmail.com-20091207215009-y0o88dedx9lz2fl8
Split some classes from the range optimizer out in to their own header and implementation files.
Corrected the case on these classes also to adhere to the coding standards. Cleaned up any style
issues in any code I came across while moving code.
Corrected the case on these classes also to adhere to the coding standards. Cleaned up any style
issues in any code I came across while moving code.
- files added:
- drizzled/optimizer/quick_index_merge_select.cc
- files modified:
- drizzled/Makefile.am
added
removed
drizzled/optimizer/quick_range_select.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
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
#ifndef DRIZZLED_OPTIMIZER_QUICK_RANGE_SELECT_H
21
#define DRIZZLED_OPTIMIZER_QUICK_RANGE_SELECT_H
22
23
#include "drizzled/optimizer/range.h"
24
25
class Cursor;
26
27
namespace drizzled
28
{
29
30
namespace optimizer
31
{
32
33
/**
34
* Quick select that does a range scan on a single key.
35
*
36
* The records are returned in key order.
37
*
38
*/
39
class QuickRangeSelect : public QuickSelectInterface
40
{
41
protected:
42
Cursor *cursor;
43
DYNAMIC_ARRAY ranges; /**< ordered array of range ptrs */
44
45
/** Members to deal with case when this quick select is a ROR-merged scan */
46
bool in_ror_merged_scan;
47
MyBitmap column_bitmap;
48
MyBitmap *save_read_set;
49
MyBitmap *save_write_set;
50
bool free_file; /**< True when this->file is "owned" by this quick select */
51
52
/* Range pointers to be used when not using MRR interface */
53
QuickRange **cur_range; /**< current element in ranges */
54
QuickRange *last_range;
55
56
/** Members needed to use the MRR interface */
57
QuickRangeSequenceContext qr_traversal_ctx;
58
uint32_t mrr_buf_size; /**< copy from session->variables.read_rnd_buff_size */
59
HANDLER_BUFFER *mrr_buf_desc; /**< the Cursor buffer */
60
61
/** Info about index we're scanning */
62
KEY_PART *key_parts;
63
KEY_PART_INFO *key_part_info;
64
65
bool dont_free; /**< Used by QuickSelectDescending */
66
67
/**
68
* Compare if found key is over max-value
69
* @return 0 if key <= range->max_key
70
* @todo: Figure out why can't this function be as simple as cmp_prev().
71
*/
72
int cmp_next(QuickRange *range);
73
74
/**
75
* @return 0 if found key is inside range (found key >= range->min_key).
76
*/
77
int cmp_prev(QuickRange *range);
78
79
/**
80
* Check if current row will be retrieved by this QuickRangeSelect
81
*
82
* NOTES
83
* It is assumed that currently a scan is being done on another index
84
* which reads all necessary parts of the index that is scanned by this
85
* quick select.
86
* The implementation does a binary search on sorted array of disjoint
87
* ranges, without taking size of range into account.
88
*
89
* This function is used to filter out clustered PK scan rows in
90
* index_merge quick select.
91
*
92
* RETURN
93
* @retval true if current row will be retrieved by this quick select
94
* false if not
95
*/
96
bool row_in_ranges();
97
98
public:
99
100
uint32_t mrr_flags; /**< Flags to be used with MRR interface */
101
102
MEM_ROOT alloc;
103
104
QuickRangeSelect(Session *session,
105
Table *table,
106
uint32_t index_arg,
107
bool no_alloc,
108
MEM_ROOT *parent_alloc,
109
bool *create_err);
110
111
~QuickRangeSelect();
112
113
int init();
114
115
int reset(void);
116
117
/**
118
* Get next possible record using quick-struct.
119
*
120
* SYNOPSIS
121
* QuickRangeSelect::get_next()
122
*
123
* NOTES
124
* Record is read into table->record[0]
125
*
126
* RETURN
127
* @retval 0 Found row
128
* @retval HA_ERR_END_OF_FILE No (more) rows in range
129
* @retaval # Error code
130
*/
131
int get_next();
132
133
void range_end();
134
135
/**
136
* Get the next record with a different prefix.
137
*
138
* SYNOPSIS
139
* QuickRangeSelect::get_next_prefix()
140
* @param[in] prefix_length length of cur_prefix
141
* @param[in] cur_prefix prefix of a key to be searched for
142
*
143
* DESCRIPTION
144
* Each subsequent call to the method retrieves the first record that has a
145
* prefix with length prefix_length different from cur_prefix, such that the
146
* record with the new prefix is within the ranges described by
147
* this->ranges. The record found is stored into the buffer pointed by
148
* this->record.
149
* The method is useful for GROUP-BY queries with range conditions to
150
* discover the prefix of the next group that satisfies the range conditions.
151
*
152
* @todo
153
* This method is a modified copy of QuickRangeSelect::get_next(), so both
154
* methods should be unified into a more general one to reduce code
155
* duplication.
156
*
157
* RETURN
158
* @retval 0 on success
159
* @retval HA_ERR_END_OF_FILE if returned all keys
160
* @retval other if some error occurred
161
*/
162
int get_next_prefix(uint32_t prefix_length,
163
key_part_map keypart_map,
164
unsigned char *cur_prefix);
165
166
bool reverse_sorted()
167
{
168
return false;
169
}
170
171
/**
172
* @return true if there is only one range and this uses the whole primary key
173
*/
174
bool unique_key_range();
175
176
/**
177
* Initialize this quick select to be a ROR-merged scan.
178
*
179
* SYNOPSIS
180
* QuickRangeSelect::init_ror_merged_scan()
181
* @param[in] reuse_handler If true, use head->cursor, otherwise create a separate Cursor object
182
*
183
* NOTES
184
* This function creates and prepares for subsequent use a separate Cursor
185
* object if it can't reuse head->cursor. The reason for this is that during
186
* ROR-merge several key scans are performed simultaneously, and a single
187
* Cursor is only capable of preserving context of a single key scan.
188
*
189
* In ROR-merge the quick select doing merge does full records retrieval,
190
* merged quick selects read only keys.
191
*
192
* RETURN
193
* @reval 0 ROR child scan initialized, ok to use.
194
* @retval 1 error
195
*/
196
int init_ror_merged_scan(bool reuse_handler);
197
198
void save_last_pos();
199
200
int get_type()
201
{
202
return QS_TYPE_RANGE;
203
}
204
205
void add_keys_and_lengths(String *key_names, String *used_lengths);
206
207
void add_info_string(String *str);
208
209
void resetCursor()
210
{
211
cursor= NULL;
212
}
213
214
private:
215
216
/* Used only by QuickSelectDescending */
217
QuickRangeSelect(const QuickRangeSelect& org) : QuickSelectInterface()
218
{
219
memmove(this, &org, sizeof(*this));
220
/*
221
Use default MRR implementation for reverse scans. No table engine
222
currently can do an MRR scan with output in reverse index order.
223
*/
224
mrr_buf_desc= NULL;
225
mrr_flags|= HA_MRR_USE_DEFAULT_IMPL;
226
mrr_buf_size= 0;
227
}
228
229
friend class ::TRP_ROR_INTERSECT;
230
231
friend
232
QuickRangeSelect *get_quick_select_for_ref(Session *session, Table *table,
233
struct table_reference_st *ref,
234
ha_rows records);
235
236
friend bool get_quick_keys(PARAM *param,
237
QuickRangeSelect *quick,
238
KEY_PART *key,
239
SEL_ARG *key_tree,
240
unsigned char *min_key,
241
uint32_t min_key_flag,
242
unsigned char *max_key,
243
uint32_t max_key_flag);
244
245
friend QuickRangeSelect *get_quick_select(PARAM*,uint32_t idx,
246
SEL_ARG *key_tree,
247
uint32_t mrr_flags,
248
uint32_t mrr_buf_size,
249
MEM_ROOT *alloc);
250
friend class QuickSelectDescending;
251
252
friend class QuickIndexMergeSelect;
253
254
friend class QUICK_ROR_INTERSECT_SELECT;
255
256
friend class QUICK_GROUP_MIN_MAX_SELECT;
257
258
friend uint32_t quick_range_seq_next(range_seq_t rseq, KEY_MULTI_RANGE *range);
259
260
friend range_seq_t quick_range_seq_init(void *init_param,
261
uint32_t n_ranges,
262
uint32_t flags);
263
264
friend void select_describe(JOIN *join,
265
bool need_tmp_table,
266
bool need_order,
267
bool distinct,
268
const char *message);
269
};
270
271
class QuickSelectDescending : public QuickRangeSelect
272
{
273
public:
274
275
QuickSelectDescending(QuickRangeSelect *q,
276
uint32_t used_key_parts,
277
bool *create_err);
278
279
int get_next();
280
281
bool reverse_sorted()
282
{
283
return true;
284
}
285
286
int get_type()
287
{
288
return QS_TYPE_RANGE_DESC;
289
}
290
291
private:
292
293
bool range_reads_after_key(QuickRange *range);
294
295
int reset(void)
296
{
297
rev_it.rewind();
298
return QuickRangeSelect::reset();
299
}
300
301
List<QuickRange> rev_ranges;
302
303
List_iterator<QuickRange> rev_it;
304
305
};
306
307
} /* namespace optimizer */
308
309
} /* namespace drizzled */
310
311
#endif /* DRIZZLED_OPTIMIZER_QUICK_RANGE_SELECT_H */
Loggerhead is a web-based interface for Breezy
Version: 2.0.1