MySQL  8.0.27
Source Code Documentation
debug_sync.h
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1 #ifndef DEBUG_SYNC_INCLUDED
2 #define DEBUG_SYNC_INCLUDED
3 
4 /* Copyright (c) 2009, 2021, Oracle and/or its affiliates.
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, version 2.0,
8  as published by the Free Software Foundation.
9 
10  This program is also distributed with certain software (including
11  but not limited to OpenSSL) that is licensed under separate terms,
12  as designated in a particular file or component or in included license
13  documentation. The authors of MySQL hereby grant you an additional
14  permission to link the program and your derivative works with the
15  separately licensed software that they have included with MySQL.
16 
17  This program is distributed in the hope that it will be useful,
18  but WITHOUT ANY WARRANTY; without even the implied warranty of
19  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20  GNU General Public License, version 2.0, for more details.
21 
22  You should have received a copy of the GNU General Public License
23  along with this program; if not, write to the Free Software
24  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
25 
26 /**
27  @file
28 
29  Declarations for the Debug Sync Facility. See debug_sync.cc for details.
30 */
31 
32 #include <stddef.h>
33 #include <sys/types.h>
34 
35 #include "m_string.h"
36 #include "my_compiler.h"
37 #include "my_inttypes.h"
38 #include "my_sharedlib.h"
39 
40 class THD;
41 
42 #if defined(ENABLED_DEBUG_SYNC)
43 
44 /* Macro to be put in the code at synchronization points. */
45 #define DEBUG_SYNC(_thd_, _sync_point_name_) \
46  do { \
47  if (unlikely(opt_debug_sync_timeout)) \
48  debug_sync(_thd_, STRING_WITH_LEN(_sync_point_name_)); \
49  } while (0)
50 
51 /* Command line option --debug-sync-timeout. See mysqld.cc. */
52 extern MYSQL_PLUGIN_IMPORT uint opt_debug_sync_timeout;
53 
54 /* Default WAIT_FOR timeout if command line option is given without argument. */
55 #define DEBUG_SYNC_DEFAULT_WAIT_TIMEOUT 300
56 
57 /* Debug Sync prototypes. See debug_sync.cc. */
58 extern int debug_sync_init(void);
59 extern void debug_sync_end(void);
60 extern void debug_sync_init_thread(THD *thd);
61 extern void debug_sync_claim_memory_ownership(THD *thd, bool claim);
62 extern void debug_sync_end_thread(THD *thd);
63 extern void debug_sync(THD *thd, const char *sync_point_name, size_t name_len);
64 extern bool debug_sync_set_action(THD *thd, const char *action_str, size_t len);
65 extern bool debug_sync_update(THD *thd, char *val_str);
66 extern uchar *debug_sync_value_ptr(THD *thd);
67 extern void conditional_sync_point_for_timestamp(std::string name);
68 extern void conditional_sync_point(std::string name);
69 
70 /**
71  This macro simplifies when a DBUG_EXECUTE_IF will generate a given
72  signal and then will wait for another signal to continue.
73 */
74 #define DBUG_SIGNAL_WAIT_FOR(T, A, B, C) \
75  DBUG_EXECUTE_IF(A, { \
76  const char act[] = "now SIGNAL " B " WAIT_FOR " C; \
77  assert(!debug_sync_set_action(T, STRING_WITH_LEN(act))); \
78  };)
79 
80 /**
81  Set a sync point that is activated by setting
82  @@debug='d,syncpoint_NAME', and which will emit the signal
83  "reached_NAME" and wait for the signal "continue_NAME"
84 
85  @param[in] NAME The name of the debug symbol. This should indicate
86  the logical point in time in the code flow where it
87  appears. Usually it should have the form "before_EVENT" or
88  "after_EVENT", where EVENT identifies something that the code
89  does. EVENT might for instance be the name of a function in the
90  source code. The sync point might be reused by multiple tests, so
91  the name should relate to what the server does and not the test
92  scenario.
93  */
94 #define CONDITIONAL_SYNC_POINT(NAME) conditional_sync_point(NAME)
95 
96 /**
97  Set a sync point that is activated by setting
98  @@debug='d,syncpoint_NAME_TIMESTAMP', where NAME is given as an
99  argument and TIMESTAMP must match the value of @@session.timestamp
100  for the thread. When activated, the sync point will emit the
101  signal "reached_NAME_TIMESTAMP", and wait for the signal
102  "continue_NAME_TIMESTAMP".
103 
104  @param[in] NAME The name of the debug symbol. This should indicate
105  the logical point in time in the code flow where it
106  appears. Usually it should have the form "before_EVENT" or
107  "after_EVENT", where EVENT identifies something that the code
108  does. EVENT might for instance be the name of a function in the
109  source code. The sync point might be reused by multiple tests, so
110  the name should relate to what the server does and not the test
111  scenario.
112 
113  @param[in] TIMESTAMP The timestamp. Only threads where the session
114  variable @@session.timestamp is set to TIMESTAMP will be
115  affected. TIMESTAMP will be appended to the debug symbol, to the
116  signals that the sync point emits and waits for.
117 */
118 #define CONDITIONAL_SYNC_POINT_FOR_TIMESTAMP(NAME) \
119  conditional_sync_point_for_timestamp(NAME)
120 
121 #else /* defined(ENABLED_DEBUG_SYNC) */
122 
123 #define DEBUG_SYNC(_thd_, _sync_point_name_) /* disabled DEBUG_SYNC */
124 #define DBUG_SIGNAL_WAIT_FOR(T, A, B, C) \
125  do { \
126  } while (0)
127 #define CONDITIONAL_SYNC_POINT(NAME)
128 #define CONDITIONAL_SYNC_POINT_FOR_TIMESTAMP(NAME)
129 
130 #endif /* defined(ENABLED_DEBUG_SYNC) */
131 
132 #endif /* DEBUG_SYNC_INCLUDED */
For each client connection we create a separate thread with THD serving as a thread/connection descri...
Definition: sql_class.h:821
Header for compiler-dependent features.
Some integer typedefs for easier portability.
unsigned char uchar
Definition: my_inttypes.h:51
Functions related to handling of plugins and other dynamically loaded libraries.
#define MYSQL_PLUGIN_IMPORT
Definition: my_sharedlib.h:70
case opt name
Definition: sslopt-case.h:32
unsigned int uint
Definition: uca-dump.cc:29