init

db_include/postmaster/bgworker_internals.h

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+/*--------------------------------------------------------------------
+ * bgworker_internals.h
+ *		POSTGRES pluggable background workers internals
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ *		src/include/postmaster/bgworker_internals.h
+ *--------------------------------------------------------------------
+ */
+#ifndef BGWORKER_INTERNALS_H
+#define BGWORKER_INTERNALS_H
+
+#include "datatype/timestamp.h"
+#include "lib/ilist.h"
+#include "postmaster/bgworker.h"
+
+/* GUC options */
+
+/*
+ * Maximum possible value of parallel workers.
+ */
+#define MAX_PARALLEL_WORKER_LIMIT 1024
+
+/*
+ * List of background workers, private to postmaster.
+ *
+ * A worker that requests a database connection during registration will have
+ * rw_backend set, and will be present in BackendList.  Note: do not rely on
+ * rw_backend being non-NULL for shmem-connected workers!
+ */
+typedef struct RegisteredBgWorker
+{
+	BackgroundWorker rw_worker; /* its registry entry */
+	struct bkend *rw_backend;	/* its BackendList entry, or NULL */
+	pid_t		rw_pid;			/* 0 if not running */
+	int			rw_child_slot;
+	TimestampTz rw_crashed_at;	/* if not 0, time it last crashed */
+	int			rw_shmem_slot;
+	bool		rw_terminate;
+	slist_node	rw_lnode;		/* list link */
+} RegisteredBgWorker;
+
+extern slist_head BackgroundWorkerList;
+
+extern Size BackgroundWorkerShmemSize(void);
+extern void BackgroundWorkerShmemInit(void);
+extern void BackgroundWorkerStateChange(bool allow_new_workers);
+extern void ForgetBackgroundWorker(slist_mutable_iter *cur);
+extern void ReportBackgroundWorkerPID(RegisteredBgWorker *);
+extern void ReportBackgroundWorkerExit(slist_mutable_iter *cur);
+extern void BackgroundWorkerStopNotifications(pid_t pid);
+extern void ForgetUnstartedBackgroundWorkers(void);
+extern void ResetBackgroundWorkerCrashTimes(void);
+
+/* Function to start a background worker, called from postmaster.c */
+extern void StartBackgroundWorker(void) pg_attribute_noreturn();
+
+#ifdef EXEC_BACKEND
+extern BackgroundWorker *BackgroundWorkerEntry(int slotno);
+#endif
+
+#endif							/* BGWORKER_INTERNALS_H */