1/*--------------------------------------------------------------------
2 * bgworker_internals.h
3 * POSTGRES pluggable background workers internals
4 *
5 * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
6 * Portions Copyright (c) 1994, Regents of the University of California
7 *
8 * IDENTIFICATION
9 * src/include/postmaster/bgworker_internals.h
10 *--------------------------------------------------------------------
11 */
12#ifndef BGWORKER_INTERNALS_H
13#define BGWORKER_INTERNALS_H
14
15#include "datatype/timestamp.h"
16#include "lib/ilist.h"
17#include "postmaster/bgworker.h"
18
19/* GUC options */
20
21/*
22 * Maximum possible value of parallel workers.
23 */
24#define MAX_PARALLEL_WORKER_LIMIT 1024
25
26/*
27 * List of background workers, private to postmaster.
28 *
29 * A worker that requests a database connection during registration will have
30 * rw_backend set, and will be present in BackendList. Note: do not rely on
31 * rw_backend being non-NULL for shmem-connected workers!
32 */
33typedef struct RegisteredBgWorker
34{
35 BackgroundWorker rw_worker; /* its registry entry */
36 struct bkend *rw_backend; /* its BackendList entry, or NULL */
37 pid_t rw_pid; /* 0 if not running */
38 int rw_child_slot;
39 TimestampTz rw_crashed_at; /* if not 0, time it last crashed */
40 int rw_shmem_slot;
41 bool rw_terminate;
42 slist_node rw_lnode; /* list link */
43} RegisteredBgWorker;
44
45extern slist_head BackgroundWorkerList;
46
47extern Size BackgroundWorkerShmemSize(void);
48extern void BackgroundWorkerShmemInit(void);
49extern void BackgroundWorkerStateChange(void);
50extern void ForgetBackgroundWorker(slist_mutable_iter *cur);
51extern void ReportBackgroundWorkerPID(RegisteredBgWorker *);
52extern void ReportBackgroundWorkerExit(slist_mutable_iter *cur);
53extern void BackgroundWorkerStopNotifications(pid_t pid);
54extern void ResetBackgroundWorkerCrashTimes(void);
55
56/* Function to start a background worker, called from postmaster.c */
57extern void StartBackgroundWorker(void) pg_attribute_noreturn();
58
59#ifdef EXEC_BACKEND
60extern BackgroundWorker *BackgroundWorkerEntry(int slotno);
61#endif
62
63#endif /* BGWORKER_INTERNALS_H */
64