MySQL 5.6.14 Source Code Document
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ha_blackhole.h
1 /* Copyright (c) 2005, 2011, Oracle and/or its affiliates. All rights reserved.
2 
3  This program is free software; you can redistribute it and/or modify
4  it under the terms of the GNU General Public License as published by
5  the Free Software Foundation; version 2 of the License.
6 
7  This program is distributed in the hope that it will be useful,
8  but WITHOUT ANY WARRANTY; without even the implied warranty of
9  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10  GNU General Public License for more details.
11 
12  You should have received a copy of the GNU General Public License
13  along with this program; if not, write to the Free Software
14  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
15 
16 #include "thr_lock.h" /* THR_LOCK */
17 #include "handler.h" /* handler */
18 #include "table.h" /* TABLE_SHARE */
19 
20 /*
21  Shared structure for correct LOCK operation
22 */
23 struct st_blackhole_share {
24  THR_LOCK lock;
25  uint use_count;
26  uint table_name_length;
27  char table_name[1];
28 };
29 
30 
31 /*
32  Class definition for the blackhole storage engine
33  "Dumbest named feature ever"
34 */
35 class ha_blackhole: public handler
36 {
37  THR_LOCK_DATA lock; /* MySQL lock */
38  st_blackhole_share *share;
39 
40 public:
41  ha_blackhole(handlerton *hton, TABLE_SHARE *table_arg);
42  ~ha_blackhole()
43  {
44  }
45  /* The name that will be used for display purposes */
46  const char *table_type() const { return "BLACKHOLE"; }
47  /*
48  The name of the index type that will be used for display
49  don't implement this method unless you really have indexes
50  */
51  const char *index_type(uint key_number);
52  const char **bas_ext() const;
53  ulonglong table_flags() const
54  {
55  return(HA_NULL_IN_KEY | HA_CAN_FULLTEXT | HA_CAN_SQL_HANDLER |
56  HA_BINLOG_STMT_CAPABLE | HA_BINLOG_ROW_CAPABLE |
57  HA_CAN_INDEX_BLOBS | HA_AUTO_PART_KEY | HA_READ_OUT_OF_SYNC |
58  HA_FILE_BASED | HA_CAN_GEOMETRY | HA_CAN_INSERT_DELAYED);
59  }
60  ulong index_flags(uint inx, uint part, bool all_parts) const
61  {
62  return ((table_share->key_info[inx].algorithm == HA_KEY_ALG_FULLTEXT) ?
63  0 : HA_READ_NEXT | HA_READ_PREV | HA_READ_RANGE |
64  HA_READ_ORDER | HA_KEYREAD_ONLY);
65  }
66  /* The following defines can be increased if necessary */
67 #define BLACKHOLE_MAX_KEY 64 /* Max allowed keys */
68 #define BLACKHOLE_MAX_KEY_SEG 16 /* Max segments for key */
69 #define BLACKHOLE_MAX_KEY_LENGTH 1000
70  uint max_supported_keys() const { return BLACKHOLE_MAX_KEY; }
71  uint max_supported_key_length() const { return BLACKHOLE_MAX_KEY_LENGTH; }
72  uint max_supported_key_part_length() const { return BLACKHOLE_MAX_KEY_LENGTH; }
73  int open(const char *name, int mode, uint test_if_locked);
74  int close(void);
75  int truncate();
76  int rnd_init(bool scan);
77  int rnd_next(uchar *buf);
78  int rnd_pos(uchar * buf, uchar *pos);
79  int index_read_map(uchar * buf, const uchar * key, key_part_map keypart_map,
80  enum ha_rkey_function find_flag);
81  int index_read_idx_map(uchar * buf, uint idx, const uchar * key,
82  key_part_map keypart_map,
83  enum ha_rkey_function find_flag);
84  int index_read_last_map(uchar * buf, const uchar * key, key_part_map keypart_map);
85  int index_next(uchar * buf);
86  int index_prev(uchar * buf);
87  int index_first(uchar * buf);
88  int index_last(uchar * buf);
89  void position(const uchar *record);
90  int info(uint flag);
91  int external_lock(THD *thd, int lock_type);
92  int create(const char *name, TABLE *table_arg,
93  HA_CREATE_INFO *create_info);
94  THR_LOCK_DATA **store_lock(THD *thd,
95  THR_LOCK_DATA **to,
96  enum thr_lock_type lock_type);
97 private:
98  virtual int write_row(uchar *buf);
99  virtual int update_row(const uchar *old_data, uchar *new_data);
100  virtual int delete_row(const uchar *buf);
101 };