MySQL 8.0.30
Source Code Documentation
log_sink_perfschema.h
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15but WITHOUT ANY WARRANTY; without even the implied warranty of
16MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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20along with this program; if not, write to the Free Software
21Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
22
23/**
24 @file sql/server_component/log_sink_perfschema.h
25
26 This file contains
27
28 a) The API for the reading of previously written error logs.
29 (These functions will in turn use a parse-function defined
30 in a log-sink. Whichever log-sink that has a parse-function
31 is listed first in @@global.log_error_services will be used;
32 that service will decide what log-file to read (i.e. its name)
33 and how to parse it. We initially support the reading of JSON-
34 formatted error log files and of the traditional MySQL error
35 log files.)
36 This lets us restore error log information from previous runs
37 when the server starts.
38 These functions are called from mysqld.cc at start-up.
39
40 b) The log-sink that adds errors logged at run-time to the ring-buffer
41 (to be called from @see log_line_submit() during normal operation, i.e.
42 when loadable log-components are available, connections are accepted,
43 and so on).
44*/
45
46#ifndef LOG_SINK_PERFSCHEMA_H
47#define LOG_SINK_PERFSCHEMA_H
48
50#include "my_thread_local.h" // my_thread_id
51
52/* "MY-123456" - 6 digits, "MY-", '\0' */
53#define LOG_SINK_PFS_ERROR_CODE_LENGTH 10
54
55/* Currently one of "Repl"/"InnoDB"/"Server" + '\0' */
56#define LOG_SINK_PFS_SUBSYS_LENGTH 7
57
58typedef struct _log_sink_pfs_event {
59 /** Column ERROR_LOG_TIMESTAMP. Logger should forcibly make these unique. */
61
62 /** Column ERROR_LOG_THREAD. */
63 ulonglong m_thread_id; // PFS_key_thread_id uses ulonglong, not my_thread_id
64
65 /** Column ERROR_LOG_PRIO. */
66 ulong m_prio;
67
68 /** Column ERROR_LOG_ERROR_CODE. */
71
72 /** Column ERROR_LOG_SUBSYS. */
75
76 /** Column ERROR_LOG_MESSAGE. */
77 uint m_message_length; ///< actual length, not counting trailing '\0'
79
80/*
81 We make these public for SHOW STATUS.
82 Everybody else should use the getter functions.
83
84 The timestamp is made available to allow for
85 easy checks whether log entries were added since
86 the interested part last polled.
87 The timestamp is provided as a unique value with
88 microsecond precision for that use; to view it in
89 a more human-friendly format, use
90
91 SELECT FROM_UNIXTIME(variable_value/1000000)
92 FROM global_status WHERE variable_name="Error_log_latest_write";
93
94 Thus if you expect to check for new events with some
95 regularity, you could start off with
96
97 SELECT 0 INTO @error_log_last_poll;
98
99 and then poll using something like
100
101 SELECT logged,prio,error_code,subsystem,data
102 FROM performance_schema.error_log
103 WHERE logged>@error_log_last_poll;
104
105 SELECT FROM_UNIXTIME(variable_value/1000000)
106 FROM global_status WHERE variable_name="Error_log_latest_write"
107 INTO @error_log_last_poll;
108
109 (Ideally though you'd update @error_log_last_poll from the 'logged'
110 field (that is, the timestamp) of the last new row you received.)
111*/
112extern ulong log_sink_pfs_buffered_bytes; ///< bytes in use (now)
113extern ulong log_sink_pfs_buffered_events; ///< events in buffer (now)
114extern ulong log_sink_pfs_expired_events; ///< number of expired entries (ever)
115extern ulong log_sink_pfs_longest_event; ///< longest event seen (ever)
116extern ulonglong
117 log_sink_pfs_latest_timestamp; ///< timestamp of most recent write
118
119// The public interface to reading the error-log from the ring-buffer:
120
121/// Acquire a read-lock on the ring-buffer.
123
124/// Release read-lock on ring-buffer.
126
127/**
128 Get number of events currently in ring-buffer.
129 Caller should hold THR_LOCK_log_perschema when reading this.
130
131 @returns number of events current in ring-buffer (0..)
132*/
134
135/**
136 Get oldest event still in ring-buffer.
137 Caller should hold read-lock on THR_LOCK_log_perfschema when calling this.
138
139 @returns nullptr No events in buffer
140 @returns otherwise Address of oldest event in ring-buffer
141*/
143
145
147 ulonglong logged);
148
149// The public interface to restoring the error-log to the ring-buffer:
150
151/**
152 Set up ring-buffer for error-log.
153
154 @returns 0 Success - buffer was allocated.
155 @returns !=0 Failure - buffer was not allocated.
156*/
158
159/**
160 Release error log ring-buffer.
161
162 @returns 0 Success - buffer was released, or did not exist in the first
163 place.
164*/
166
167log_service_error log_error_read_log(const char *log_name);
168
170 const char *blob_src);
171
172int log_sink_perfschema(void *instance [[maybe_unused]], log_line *ll);
173
174#endif /* LOG_SINK_PERFSCHEMA_H */
enum enum_log_service_error log_service_error
Error codes.
unsigned long long int ulonglong
Definition: my_inttypes.h:55
log_service_error log_sink_pfs_event_add(log_sink_pfs_event *e, const char *blob_src)
Add a log-event to the ring buffer.
Definition: log_sink_perfschema.cc:383
ulonglong log_sink_pfs_latest_timestamp
timestamp of most recent write
Definition: log_sink_perfschema.cc:84
log_service_error log_error_read_log(const char *log_name)
Restore error log messages from previous shutdown.
Definition: log_sink_perfschema.cc:686
ulong log_sink_pfs_buffered_bytes
bytes in use (now)
Definition: log_sink_perfschema.cc:80
int log_error_read_log_init()
Set up ring-buffer for error-log.
Definition: log_sink_perfschema.cc:775
ulong log_sink_pfs_expired_events
number of expired entries (ever)
Definition: log_sink_perfschema.cc:82
void log_sink_pfs_read_end()
Release read-lock on ring-buffer.
Definition: log_sink_perfschema.cc:142
#define LOG_SINK_PFS_SUBSYS_LENGTH
Definition: log_sink_perfschema.h:56
int log_error_read_log_exit()
Release error log ring-buffer.
Definition: log_sink_perfschema.cc:749
log_sink_pfs_event * log_sink_pfs_event_first()
Get oldest event still in ring-buffer.
Definition: log_sink_perfschema.cc:159
void log_sink_pfs_read_start()
Acquire a read-lock on the ring-buffer.
Definition: log_sink_perfschema.cc:135
size_t log_sink_pfs_event_count()
Get number of events currently in ring-buffer.
Definition: log_sink_perfschema.cc:150
ulong log_sink_pfs_longest_event
longest event seen (ever)
Definition: log_sink_perfschema.cc:83
struct _log_sink_pfs_event log_sink_pfs_event
log_sink_pfs_event * log_sink_pfs_event_valid(log_sink_pfs_event *e, ulonglong logged)
Use timestamp to check whether a given event-pointer still points to a valid event in the ring-buffer...
Definition: log_sink_perfschema.cc:234
ulong log_sink_pfs_buffered_events
events in buffer (now)
Definition: log_sink_perfschema.cc:81
int log_sink_perfschema(void *instance, log_line *ll)
services: log sinks: logging to performance_schema ring-buffer
Definition: log_sink_perfschema.cc:813
log_sink_pfs_event * log_sink_pfs_event_next(log_sink_pfs_event *e)
Get event following the supplied one.
Definition: log_sink_perfschema.cc:183
#define LOG_SINK_PFS_ERROR_CODE_LENGTH
Definition: log_sink_perfschema.h:53
log_line ("log event")
Definition: keyring_log_builtins_definition.cc:71
Definition: log_sink_perfschema.h:58
ulonglong m_thread_id
Column ERROR_LOG_THREAD.
Definition: log_sink_perfschema.h:63
char m_error_code[LOG_SINK_PFS_ERROR_CODE_LENGTH]
Column ERROR_LOG_ERROR_CODE.
Definition: log_sink_perfschema.h:69
uint m_message_length
Column ERROR_LOG_MESSAGE.
Definition: log_sink_perfschema.h:77
ulonglong m_timestamp
Column ERROR_LOG_TIMESTAMP.
Definition: log_sink_perfschema.h:60
uint m_subsys_length
Definition: log_sink_perfschema.h:74
char m_subsys[LOG_SINK_PFS_SUBSYS_LENGTH]
Column ERROR_LOG_SUBSYS.
Definition: log_sink_perfschema.h:73
ulong m_prio
Column ERROR_LOG_PRIO.
Definition: log_sink_perfschema.h:66
uint m_error_code_length
Definition: log_sink_perfschema.h:70
unsigned int uint
Definition: uca-dump.cc:29