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procsignal.h
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1 /*-------------------------------------------------------------------------
2  *
3  * procsignal.h
4  * Routines for interprocess signalling
5  *
6  *
7  * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
8  * Portions Copyright (c) 1994, Regents of the University of California
9  *
10  * src/include/storage/procsignal.h
11  *
12  *-------------------------------------------------------------------------
13  */
14 #ifndef PROCSIGNAL_H
15 #define PROCSIGNAL_H
16 
17 #include "storage/backendid.h"
18 
19 
20 /*
21  * Reasons for signalling a Postgres child process (a backend or an auxiliary
22  * process, like checkpointer). We can cope with concurrent signals for different
23  * reasons. However, if the same reason is signaled multiple times in quick
24  * succession, the process is likely to observe only one notification of it.
25  * This is okay for the present uses.
26  *
27  * Also, because of race conditions, it's important that all the signals be
28  * defined so that no harm is done if a process mistakenly receives one.
29  */
30 typedef enum
31 {
32  PROCSIG_CATCHUP_INTERRUPT, /* sinval catchup interrupt */
33  PROCSIG_NOTIFY_INTERRUPT, /* listen/notify interrupt */
34  PROCSIG_PARALLEL_MESSAGE, /* message from cooperating parallel backend */
35  PROCSIG_WALSND_INIT_STOPPING, /* ask walsenders to prepare for shutdown */
36 
37  /* Recovery conflict reasons */
44 
45  NUM_PROCSIGNALS /* Must be last! */
47 
48 typedef enum
49 {
50  /*
51  * XXX. PROCSIGNAL_BARRIER_PLACEHOLDER should be replaced when the first
52  * real user of the ProcSignalBarrier mechanism is added. It's just here
53  * for now because we can't have an empty enum.
54  */
57 
58 /*
59  * prototypes for functions in procsignal.c
60  */
61 extern Size ProcSignalShmemSize(void);
62 extern void ProcSignalShmemInit(void);
63 
64 extern void ProcSignalInit(int pss_idx);
65 extern int SendProcSignal(pid_t pid, ProcSignalReason reason,
66  BackendId backendId);
67 
69 extern void WaitForProcSignalBarrier(uint64 generation);
70 extern void ProcessProcSignalBarrier(void);
71 
73 
74 #endif /* PROCSIGNAL_H */
void ProcSignalInit(int pss_idx)
Definition: procsignal.c:151
void ProcSignalShmemInit(void)
Definition: procsignal.c:116
void WaitForProcSignalBarrier(uint64 generation)
Definition: procsignal.c:382
Size ProcSignalShmemSize(void)
Definition: procsignal.c:102
void ProcessProcSignalBarrier(void)
Definition: procsignal.c:429
uint64 EmitProcSignalBarrier(ProcSignalBarrierType type)
Definition: procsignal.c:321
int BackendId
Definition: backendid.h:21
void procsignal_sigusr1_handler(SIGNAL_ARGS)
Definition: procsignal.c:533
#define SIGNAL_ARGS
Definition: c.h:1296
size_t Size
Definition: c.h:466
ProcSignalBarrierType
Definition: procsignal.h:48
ProcSignalReason
Definition: procsignal.h:30
int SendProcSignal(pid_t pid, ProcSignalReason reason, BackendId backendId)
Definition: procsignal.c:250