Age Owner TLA Line data Source code
1 : /*-------------------------------------------------------------------------
2 : * wait_event.h
3 : * Definitions related to wait event reporting
4 : *
5 : * Copyright (c) 2001-2025, PostgreSQL Global Development Group
6 : *
7 : * src/include/utils/wait_event.h
8 : * ----------
9 : */
10 : #ifndef WAIT_EVENT_H
11 : #define WAIT_EVENT_H
12 :
13 : /* enums for wait events */
14 : #include "utils/wait_event_types.h"
15 :
16 : extern const char *pgstat_get_wait_event(uint32 wait_event_info);
17 : extern const char *pgstat_get_wait_event_type(uint32 wait_event_info);
18 : static inline void pgstat_report_wait_start(uint32 wait_event_info);
19 : static inline void pgstat_report_wait_end(void);
20 : extern void pgstat_set_wait_event_storage(uint32 *wait_event_info);
21 : extern void pgstat_reset_wait_event_storage(void);
22 :
23 : extern PGDLLIMPORT uint32 *my_wait_event_info;
24 :
25 :
26 : /*
27 : * Wait Events - Extension, InjectionPoint
28 : *
29 : * Use InjectionPoint when the server process is waiting in an injection
30 : * point. Use Extension for other cases of the server process waiting for
31 : * some condition defined by an extension module.
32 : *
33 : * Extensions can define their own wait events in these categories. They
34 : * should call one of these functions with a wait event string. If the wait
35 : * event associated to a string is already allocated, it returns the wait
36 : * event information to use. If not, it gets one wait event ID allocated from
37 : * a shared counter, associates the string to the ID in the shared dynamic
38 : * hash and returns the wait event information.
39 : *
40 : * The ID retrieved can be used with pgstat_report_wait_start() or equivalent.
41 : */
42 : extern uint32 WaitEventExtensionNew(const char *wait_event_name);
43 : extern uint32 WaitEventInjectionPointNew(const char *wait_event_name);
44 :
45 : extern void WaitEventCustomShmemInit(void);
46 : extern Size WaitEventCustomShmemSize(void);
47 : extern char **GetWaitEventCustomNames(uint32 classId, int *nwaitevents);
48 :
49 : /* ----------
50 : * pgstat_report_wait_start() -
51 : *
52 : * Called from places where server process needs to wait. This is called
53 : * to report wait event information. The wait information is stored
54 : * as 4-bytes where first byte represents the wait event class (type of
55 : * wait, for different types of wait, refer WaitClass) and the next
56 : * 3-bytes represent the actual wait event. Currently 2-bytes are used
57 : * for wait event which is sufficient for current usage, 1-byte is
58 : * reserved for future usage.
59 : *
60 : * Historically we used to make this reporting conditional on
61 : * pgstat_track_activities, but the check for that seems to add more cost
62 : * than it saves.
63 : *
64 : * my_wait_event_info initially points to local memory, making it safe to
65 : * call this before MyProc has been initialized.
66 : * ----------
67 : */
68 : static inline void
1618 andres@anarazel.de 69 CBC 9332338 : pgstat_report_wait_start(uint32 wait_event_info)
70 : {
71 : /*
72 : * Since this is a four-byte field which is always read and written as
73 : * four-bytes, updates are atomic.
74 : */
1617 75 9332338 : *(volatile uint32 *) my_wait_event_info = wait_event_info;
1618 76 9332338 : }
77 :
78 : /* ----------
79 : * pgstat_report_wait_end() -
80 : *
81 : * Called to report end of a wait.
82 : * ----------
83 : */
84 : static inline void
85 9365846 : pgstat_report_wait_end(void)
86 : {
87 : /* see pgstat_report_wait_start() */
1617 88 9365846 : *(volatile uint32 *) my_wait_event_info = 0;
1618 89 9365846 : }
90 :
91 :
92 : #endif /* WAIT_EVENT_H */
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