MySQL 8.4.3
Source Code Documentation
sql_backup_lock.h
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17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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20 You should have received a copy of the GNU General Public License
21 along with this program; if not, write to the Free Software
22 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
23
24#ifndef SQL_LOCK_INCLUDED
25#define SQL_LOCK_INCLUDED
26
27#include <sys/types.h>
28
29#include "my_sqlcommand.h" // SQLCOM_LOCK_INSTANCE, SQLCOM_UNLOCK_INSTANCE
30#include "sql/sql_cmd.h" // Sql_cmd
31
32class THD;
33
34/**
35 Sql_cmd_lock_instance represents statement LOCK INSTANCE FOR BACKUP.
36*/
37
39 public:
40 /**
41 Execute LOCK INSTANCE statement once.
42
43 @param thd Thread handler
44
45 @returns false on success, true on error
46 */
47
48 bool execute(THD *thd) override;
49
52 }
53};
54
55/**
56 Sql_cmd_unlock_instance represents statement UNLOCK INSTANCE.
57*/
58
60 public:
61 /**
62 Execute UNLOCK INSTANCE statement once.
63
64 @param thd Thread handler
65
66 @returns false on success, true on error
67 */
68
69 bool execute(THD *thd) override;
70
73 }
74};
75
76/**
77 MDL_key::BACKUP_LOCK RAII.
78 */
80 public:
81 /**
82 There are three possible results while checking if the instance is locked
83 for backup.
84 */
85 enum class Lock_result { not_locked = 0, locked = 1, oom = 2 };
86
91 delete;
93
95
96 operator Lock_result() const;
97
98 private:
99 /**
100 Try to acquire shared backup lock.
101
102 @param[in] thd Current thread context
103 @param[in] for_trx true if MDL duration is MDL_TRANSACTION
104 false if MDL duration is MDL_EXPLICIT
105
106 @return Operation status.
107 @retval Shared_backup_lock_guard::Lock_result::locked Locked shared
108 BACKUP lock.
109 @retval Shared_backup_lock_guard::Lock_result::not_locked Could not lock
110 shared BACKUP lock. Conflicting lock exists.
111 @retval Shared_backup_lock_guard::Lock_result::oom Error. Could
112 not lock shared BACKUP lock.
113 */
115 THD *thd, bool for_trx);
118};
119
120/**
121 Acquire exclusive Backup Lock.
122
123 @param[in] thd Current thread context
124 @param[in] lock_wait_timeout How many seconds to wait before timeout.
125 @param[in] for_trx true if MDL duration is MDL_TRANSACTION
126 false if MDL duration is MDL_EXPLICIT
127
128 @return Operation status.
129 @retval false Success
130 @retval true Failure
131*/
132
133bool acquire_exclusive_backup_lock(THD *thd, unsigned long lock_wait_timeout,
134 bool for_trx);
135
136/**
137 Acquire shared Backup Lock.
138
139 @param[in] thd Current thread context
140 @param[in] lock_wait_timeout How many seconds to wait before timeout.
141 @param[in] for_trx true if MDL duration is MDL_TRANSACTION
142 false if MDL duration is MDL_EXPLICIT
143
144 @return Operation status.
145 @retval false Success
146 @retval true Failure
147*/
148
149bool acquire_shared_backup_lock(THD *thd, unsigned long lock_wait_timeout,
150 bool for_trx = true);
151
152/**
153 Release Backup Lock if it was acquired.
154
155 @param[in] thd Current thread context
156*/
157
158void release_backup_lock(THD *thd);
159
160#endif /* SQL_LOCK_INCLUDED */
MDL_key::BACKUP_LOCK RAII.
Definition: sql_backup_lock.h:79
Shared_backup_lock_guard::Lock_result try_acquire_shared_backup_lock(THD *thd, bool for_trx)
Try to acquire shared backup lock.
Definition: sql_backup_lock.cc:105
THD * m_thd
Definition: sql_backup_lock.h:117
Shared_backup_lock_guard & operator=(Shared_backup_lock_guard &&o)=default
Shared_backup_lock_guard(const Shared_backup_lock_guard &o)=delete
Shared_backup_lock_guard::Lock_result m_lock_state
Definition: sql_backup_lock.h:116
Shared_backup_lock_guard(THD *thd)
Definition: sql_backup_lock.cc:81
~Shared_backup_lock_guard()
Definition: sql_backup_lock.cc:93
Lock_result
There are three possible results while checking if the instance is locked for backup.
Definition: sql_backup_lock.h:85
Shared_backup_lock_guard & operator=(const Shared_backup_lock_guard &o)=delete
Shared_backup_lock_guard(Shared_backup_lock_guard &&o)=default
Sql_cmd_lock_instance represents statement LOCK INSTANCE FOR BACKUP.
Definition: sql_backup_lock.h:38
bool execute(THD *thd) override
Execute LOCK INSTANCE statement once.
Definition: sql_backup_lock.cc:59
enum_sql_command sql_command_code() const override
Return the command code for this statement.
Definition: sql_backup_lock.h:50
Sql_cmd_unlock_instance represents statement UNLOCK INSTANCE.
Definition: sql_backup_lock.h:59
bool execute(THD *thd) override
Execute UNLOCK INSTANCE statement once.
Definition: sql_backup_lock.cc:72
enum_sql_command sql_command_code() const override
Return the command code for this statement.
Definition: sql_backup_lock.h:71
Representation of an SQL command.
Definition: sql_cmd.h:83
For each client connection we create a separate thread with THD serving as a thread/connection descri...
Definition: sql_lexer_thd.h:36
enum_sql_command
Definition: my_sqlcommand.h:46
@ SQLCOM_LOCK_INSTANCE
Definition: my_sqlcommand.h:201
@ SQLCOM_UNLOCK_INSTANCE
Definition: my_sqlcommand.h:202
bool acquire_shared_backup_lock(THD *thd, unsigned long lock_wait_timeout, bool for_trx=true)
Acquire shared Backup Lock.
bool acquire_exclusive_backup_lock(THD *thd, unsigned long lock_wait_timeout, bool for_trx)
Acquire exclusive Backup Lock.
void release_backup_lock(THD *thd)
Release Backup Lock if it was acquired.
Definition: sql_backup_lock.cc:159
Representation of an SQL command.