Adding upstream version 14.5.upstream/14.5upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

11 files changed, 656 insertions, 0 deletions

diff --git a/src/include/postmaster/autovacuum.h b/src/include/postmaster/autovacuum.h
new file mode 100644
index 0000000..aacdd0f
--- /dev/null
+++ b/src/include/postmaster/autovacuum.h
@@ -0,0 +1,83 @@
+/*-------------------------------------------------------------------------
+ *
+ * autovacuum.h
+ *	  header file for integrated autovacuum daemon
+ *
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/postmaster/autovacuum.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef AUTOVACUUM_H
+#define AUTOVACUUM_H
+
+#include "storage/block.h"
+
+/*
+ * Other processes can request specific work from autovacuum, identified by
+ * AutoVacuumWorkItem elements.
+ */
+typedef enum
+{
+	AVW_BRINSummarizeRange
+} AutoVacuumWorkItemType;
+
+
+/* GUC variables */
+extern bool autovacuum_start_daemon;
+extern int	autovacuum_max_workers;
+extern int	autovacuum_work_mem;
+extern int	autovacuum_naptime;
+extern int	autovacuum_vac_thresh;
+extern double autovacuum_vac_scale;
+extern int	autovacuum_vac_ins_thresh;
+extern double autovacuum_vac_ins_scale;
+extern int	autovacuum_anl_thresh;
+extern double autovacuum_anl_scale;
+extern int	autovacuum_freeze_max_age;
+extern int	autovacuum_multixact_freeze_max_age;
+extern double autovacuum_vac_cost_delay;
+extern int	autovacuum_vac_cost_limit;
+
+/* autovacuum launcher PID, only valid when worker is shutting down */
+extern int	AutovacuumLauncherPid;
+
+extern int	Log_autovacuum_min_duration;
+
+/* Status inquiry functions */
+extern bool AutoVacuumingActive(void);
+extern bool IsAutoVacuumLauncherProcess(void);
+extern bool IsAutoVacuumWorkerProcess(void);
+
+#define IsAnyAutoVacuumProcess() \
+	(IsAutoVacuumLauncherProcess() || IsAutoVacuumWorkerProcess())
+
+/* Functions to start autovacuum process, called from postmaster */
+extern void autovac_init(void);
+extern int	StartAutoVacLauncher(void);
+extern int	StartAutoVacWorker(void);
+
+/* called from postmaster when a worker could not be forked */
+extern void AutoVacWorkerFailed(void);
+
+/* autovacuum cost-delay balancer */
+extern void AutoVacuumUpdateDelay(void);
+
+#ifdef EXEC_BACKEND
+extern void AutoVacLauncherMain(int argc, char *argv[]) pg_attribute_noreturn();
+extern void AutoVacWorkerMain(int argc, char *argv[]) pg_attribute_noreturn();
+extern void AutovacuumWorkerIAm(void);
+extern void AutovacuumLauncherIAm(void);
+#endif
+
+extern bool AutoVacuumRequestWork(AutoVacuumWorkItemType type,
+								  Oid relationId, BlockNumber blkno);
+
+/* shared memory stuff */
+extern Size AutoVacuumShmemSize(void);
+extern void AutoVacuumShmemInit(void);
+
+#endif							/* AUTOVACUUM_H */
diff --git a/src/include/postmaster/bgworker.h b/src/include/postmaster/bgworker.h
new file mode 100644
index 0000000..8e9ef7c
--- /dev/null
+++ b/src/include/postmaster/bgworker.h
@@ -0,0 +1,161 @@
+/*--------------------------------------------------------------------
+ * bgworker.h
+ *		POSTGRES pluggable background workers interface
+ *
+ * A background worker is a process able to run arbitrary, user-supplied code,
+ * including normal transactions.
+ *
+ * Any external module loaded via shared_preload_libraries can register a
+ * worker.  Workers can also be registered dynamically at runtime.  In either
+ * case, the worker process is forked from the postmaster and runs the
+ * user-supplied "main" function.  This code may connect to a database and
+ * run transactions.  Workers can remain active indefinitely, but will be
+ * terminated if a shutdown or crash occurs.
+ *
+ * If the fork() call fails in the postmaster, it will try again later.  Note
+ * that the failure can only be transient (fork failure due to high load,
+ * memory pressure, too many processes, etc); more permanent problems, like
+ * failure to connect to a database, are detected later in the worker and dealt
+ * with just by having the worker exit normally. A worker which exits with
+ * a return code of 0 will never be restarted and will be removed from worker
+ * list. A worker which exits with a return code of 1 will be restarted after
+ * the configured restart interval (unless that interval is BGW_NEVER_RESTART).
+ * The TerminateBackgroundWorker() function can be used to terminate a
+ * dynamically registered background worker; the worker will be sent a SIGTERM
+ * and will not be restarted after it exits.  Whenever the postmaster knows
+ * that a worker will not be restarted, it unregisters the worker, freeing up
+ * that worker's slot for use by a new worker.
+ *
+ * Note that there might be more than one worker in a database concurrently,
+ * and the same module may request more than one worker running the same (or
+ * different) code.
+ *
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ *		src/include/postmaster/bgworker.h
+ *--------------------------------------------------------------------
+ */
+#ifndef BGWORKER_H
+#define BGWORKER_H
+
+/*---------------------------------------------------------------------
+ * External module API.
+ *---------------------------------------------------------------------
+ */
+
+/*
+ * Pass this flag to have your worker be able to connect to shared memory.
+ */
+#define BGWORKER_SHMEM_ACCESS						0x0001
+
+/*
+ * This flag means the bgworker requires a database connection.  The connection
+ * is not established automatically; the worker must establish it later.
+ * It requires that BGWORKER_SHMEM_ACCESS was passed too.
+ */
+#define BGWORKER_BACKEND_DATABASE_CONNECTION		0x0002
+
+/*
+ * This class is used internally for parallel queries, to keep track of the
+ * number of active parallel workers and make sure we never launch more than
+ * max_parallel_workers parallel workers at the same time.  Third party
+ * background workers should not use this class.
+ */
+#define BGWORKER_CLASS_PARALLEL					0x0010
+/* add additional bgworker classes here */
+
+
+typedef void (*bgworker_main_type) (Datum main_arg);
+
+/*
+ * Points in time at which a bgworker can request to be started
+ */
+typedef enum
+{
+	BgWorkerStart_PostmasterStart,
+	BgWorkerStart_ConsistentState,
+	BgWorkerStart_RecoveryFinished
+} BgWorkerStartTime;
+
+#define BGW_DEFAULT_RESTART_INTERVAL	60
+#define BGW_NEVER_RESTART				-1
+#define BGW_MAXLEN						96
+#define BGW_EXTRALEN					128
+
+typedef struct BackgroundWorker
+{
+	char		bgw_name[BGW_MAXLEN];
+	char		bgw_type[BGW_MAXLEN];
+	int			bgw_flags;
+	BgWorkerStartTime bgw_start_time;
+	int			bgw_restart_time;	/* in seconds, or BGW_NEVER_RESTART */
+	char		bgw_library_name[BGW_MAXLEN];
+	char		bgw_function_name[BGW_MAXLEN];
+	Datum		bgw_main_arg;
+	char		bgw_extra[BGW_EXTRALEN];
+	pid_t		bgw_notify_pid; /* SIGUSR1 this backend on start/stop */
+} BackgroundWorker;
+
+typedef enum BgwHandleStatus
+{
+	BGWH_STARTED,				/* worker is running */
+	BGWH_NOT_YET_STARTED,		/* worker hasn't been started yet */
+	BGWH_STOPPED,				/* worker has exited */
+	BGWH_POSTMASTER_DIED		/* postmaster died; worker status unclear */
+} BgwHandleStatus;
+
+struct BackgroundWorkerHandle;
+typedef struct BackgroundWorkerHandle BackgroundWorkerHandle;
+
+/* Register a new bgworker during shared_preload_libraries */
+extern void RegisterBackgroundWorker(BackgroundWorker *worker);
+
+/* Register a new bgworker from a regular backend */
+extern bool RegisterDynamicBackgroundWorker(BackgroundWorker *worker,
+											BackgroundWorkerHandle **handle);
+
+/* Query the status of a bgworker */
+extern BgwHandleStatus GetBackgroundWorkerPid(BackgroundWorkerHandle *handle,
+											  pid_t *pidp);
+extern BgwHandleStatus WaitForBackgroundWorkerStartup(BackgroundWorkerHandle *handle, pid_t *pid);
+extern BgwHandleStatus
+			WaitForBackgroundWorkerShutdown(BackgroundWorkerHandle *);
+extern const char *GetBackgroundWorkerTypeByPid(pid_t pid);
+
+/* Terminate a bgworker */
+extern void TerminateBackgroundWorker(BackgroundWorkerHandle *handle);
+
+/* This is valid in a running worker */
+extern PGDLLIMPORT BackgroundWorker *MyBgworkerEntry;
+
+/*
+ * Connect to the specified database, as the specified user.  Only a worker
+ * that passed BGWORKER_BACKEND_DATABASE_CONNECTION during registration may
+ * call this.
+ *
+ * If username is NULL, bootstrapping superuser is used.
+ * If dbname is NULL, connection is made to no specific database;
+ * only shared catalogs can be accessed.
+ */
+extern void BackgroundWorkerInitializeConnection(const char *dbname, const char *username, uint32 flags);
+
+/* Just like the above, but specifying database and user by OID. */
+extern void BackgroundWorkerInitializeConnectionByOid(Oid dboid, Oid useroid, uint32 flags);
+
+/*
+ * Flags to BackgroundWorkerInitializeConnection et al
+ *
+ *
+ * Allow bypassing datallowconn restrictions when connecting to database
+ */
+#define BGWORKER_BYPASS_ALLOWCONN 1
+
+
+/* Block/unblock signals in a background worker process */
+extern void BackgroundWorkerBlockSignals(void);
+extern void BackgroundWorkerUnblockSignals(void);
+
+#endif							/* BGWORKER_H */
diff --git a/src/include/postmaster/bgworker_internals.h b/src/include/postmaster/bgworker_internals.h
new file mode 100644
index 0000000..fc77063
--- /dev/null
+++ b/src/include/postmaster/bgworker_internals.h
@@ -0,0 +1,64 @@
+/*--------------------------------------------------------------------
+ * 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 */
diff --git a/src/include/postmaster/bgwriter.h b/src/include/postmaster/bgwriter.h
new file mode 100644
index 0000000..c430b1b
--- /dev/null
+++ b/src/include/postmaster/bgwriter.h
@@ -0,0 +1,45 @@
+/*-------------------------------------------------------------------------
+ *
+ * bgwriter.h
+ *	  Exports from postmaster/bgwriter.c and postmaster/checkpointer.c.
+ *
+ * The bgwriter process used to handle checkpointing duties too.  Now
+ * there is a separate process, but we did not bother to split this header.
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ *
+ * src/include/postmaster/bgwriter.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef _BGWRITER_H
+#define _BGWRITER_H
+
+#include "storage/block.h"
+#include "storage/relfilenode.h"
+#include "storage/smgr.h"
+#include "storage/sync.h"
+
+
+/* GUC options */
+extern int	BgWriterDelay;
+extern int	CheckPointTimeout;
+extern int	CheckPointWarning;
+extern double CheckPointCompletionTarget;
+
+extern void BackgroundWriterMain(void) pg_attribute_noreturn();
+extern void CheckpointerMain(void) pg_attribute_noreturn();
+
+extern void RequestCheckpoint(int flags);
+extern void CheckpointWriteDelay(int flags, double progress);
+
+extern bool ForwardSyncRequest(const FileTag *ftag, SyncRequestType type);
+
+extern void AbsorbSyncRequests(void);
+
+extern Size CheckpointerShmemSize(void);
+extern void CheckpointerShmemInit(void);
+
+extern bool FirstCallSinceLastCheckpoint(void);
+
+#endif							/* _BGWRITER_H */
diff --git a/src/include/postmaster/fork_process.h b/src/include/postmaster/fork_process.h
new file mode 100644
index 0000000..64e0373
--- /dev/null
+++ b/src/include/postmaster/fork_process.h
@@ -0,0 +1,17 @@
+/*-------------------------------------------------------------------------
+ *
+ * fork_process.h
+ *	  Exports from postmaster/fork_process.c.
+ *
+ * Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ *
+ * src/include/postmaster/fork_process.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef FORK_PROCESS_H
+#define FORK_PROCESS_H
+
+extern pid_t fork_process(void);
+
+#endif							/* FORK_PROCESS_H */
diff --git a/src/include/postmaster/interrupt.h b/src/include/postmaster/interrupt.h
new file mode 100644
index 0000000..85a1293
--- /dev/null
+++ b/src/include/postmaster/interrupt.h
@@ -0,0 +1,32 @@
+/*-------------------------------------------------------------------------
+ *
+ * interrupt.h
+ *	  Interrupt handling routines.
+ *
+ * Responses to interrupts are fairly varied and many types of backends
+ * have their own implementations, but we provide a few generic things
+ * here to facilitate code reuse.
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ *	  src/include/postmaster/interrupt.h
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#ifndef INTERRUPT_H
+#define INTERRUPT_H
+
+#include <signal.h>
+
+extern PGDLLIMPORT volatile sig_atomic_t ConfigReloadPending;
+extern PGDLLIMPORT volatile sig_atomic_t ShutdownRequestPending;
+
+extern void HandleMainLoopInterrupts(void);
+extern void SignalHandlerForConfigReload(SIGNAL_ARGS);
+extern void SignalHandlerForCrashExit(SIGNAL_ARGS);
+extern void SignalHandlerForShutdownRequest(SIGNAL_ARGS);
+
+#endif
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
new file mode 100644
index 0000000..1e47a14
--- /dev/null
+++ b/src/include/postmaster/pgarch.h
@@ -0,0 +1,35 @@
+/*-------------------------------------------------------------------------
+ *
+ * pgarch.h
+ *	  Exports from postmaster/pgarch.c.
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/postmaster/pgarch.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef _PGARCH_H
+#define _PGARCH_H
+
+/* ----------
+ * Archiver control info.
+ *
+ * We expect that archivable files within pg_wal will have names between
+ * MIN_XFN_CHARS and MAX_XFN_CHARS in length, consisting only of characters
+ * appearing in VALID_XFN_CHARS.  The status files in archive_status have
+ * corresponding names with ".ready" or ".done" appended.
+ * ----------
+ */
+#define MIN_XFN_CHARS	16
+#define MAX_XFN_CHARS	40
+#define VALID_XFN_CHARS "0123456789ABCDEF.history.backup.partial"
+
+extern Size PgArchShmemSize(void);
+extern void PgArchShmemInit(void);
+extern bool PgArchCanRestart(void);
+extern void PgArchiverMain(void) pg_attribute_noreturn();
+extern void PgArchWakeup(void);
+
+#endif							/* _PGARCH_H */
diff --git a/src/include/postmaster/postmaster.h b/src/include/postmaster/postmaster.h
new file mode 100644
index 0000000..0efdd7c
--- /dev/null
+++ b/src/include/postmaster/postmaster.h
@@ -0,0 +1,78 @@
+/*-------------------------------------------------------------------------
+ *
+ * postmaster.h
+ *	  Exports from postmaster/postmaster.c.
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/postmaster/postmaster.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef _POSTMASTER_H
+#define _POSTMASTER_H
+
+/* GUC options */
+extern bool EnableSSL;
+extern int	ReservedBackends;
+extern PGDLLIMPORT int PostPortNumber;
+extern int	Unix_socket_permissions;
+extern char *Unix_socket_group;
+extern char *Unix_socket_directories;
+extern char *ListenAddresses;
+extern bool ClientAuthInProgress;
+extern int	PreAuthDelay;
+extern int	AuthenticationTimeout;
+extern bool Log_connections;
+extern bool log_hostname;
+extern bool enable_bonjour;
+extern char *bonjour_name;
+extern bool restart_after_crash;
+extern bool remove_temp_files_after_crash;
+
+#ifdef WIN32
+extern HANDLE PostmasterHandle;
+#else
+extern int	postmaster_alive_fds[2];
+
+/*
+ * Constants that represent which of postmaster_alive_fds is held by
+ * postmaster, and which is used in children to check for postmaster death.
+ */
+#define POSTMASTER_FD_WATCH		0	/* used in children to check for
+									 * postmaster death */
+#define POSTMASTER_FD_OWN		1	/* kept open by postmaster only */
+#endif
+
+extern PGDLLIMPORT const char *progname;
+
+extern void PostmasterMain(int argc, char *argv[]) pg_attribute_noreturn();
+extern void ClosePostmasterPorts(bool am_syslogger);
+extern void InitProcessGlobals(void);
+
+extern int	MaxLivePostmasterChildren(void);
+
+extern bool PostmasterMarkPIDForWorkerNotify(int);
+
+#ifdef EXEC_BACKEND
+extern pid_t postmaster_forkexec(int argc, char *argv[]);
+extern void SubPostmasterMain(int argc, char *argv[]) pg_attribute_noreturn();
+
+extern Size ShmemBackendArraySize(void);
+extern void ShmemBackendArrayAllocation(void);
+#endif
+
+/*
+ * Note: MAX_BACKENDS is limited to 2^18-1 because that's the width reserved
+ * for buffer references in buf_internals.h.  This limitation could be lifted
+ * by using a 64bit state; but it's unlikely to be worthwhile as 2^18-1
+ * backends exceed currently realistic configurations. Even if that limitation
+ * were removed, we still could not a) exceed 2^23-1 because inval.c stores
+ * the backend ID as a 3-byte signed integer, b) INT_MAX/4 because some places
+ * compute 4*MaxBackends without any overflow check.  This is rechecked in the
+ * relevant GUC check hooks and in RegisterBackgroundWorker().
+ */
+#define MAX_BACKENDS	0x3FFFF
+
+#endif							/* _POSTMASTER_H */
diff --git a/src/include/postmaster/startup.h b/src/include/postmaster/startup.h
new file mode 100644
index 0000000..bf6adf1
--- /dev/null
+++ b/src/include/postmaster/startup.h
@@ -0,0 +1,22 @@
+/*-------------------------------------------------------------------------
+ *
+ * startup.h
+ *	  Exports from postmaster/startup.c.
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ *
+ * src/include/postmaster/startup.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef _STARTUP_H
+#define _STARTUP_H
+
+extern void HandleStartupProcInterrupts(void);
+extern void StartupProcessMain(void) pg_attribute_noreturn();
+extern void PreRestoreCommand(void);
+extern void PostRestoreCommand(void);
+extern bool IsPromoteSignaled(void);
+extern void ResetPromoteSignaled(void);
+
+#endif							/* _STARTUP_H */
diff --git a/src/include/postmaster/syslogger.h b/src/include/postmaster/syslogger.h
new file mode 100644
index 0000000..1491eec
--- /dev/null
+++ b/src/include/postmaster/syslogger.h
@@ -0,0 +1,98 @@
+/*-------------------------------------------------------------------------
+ *
+ * syslogger.h
+ *	  Exports from postmaster/syslogger.c.
+ *
+ * Copyright (c) 2004-2021, PostgreSQL Global Development Group
+ *
+ * src/include/postmaster/syslogger.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef _SYSLOGGER_H
+#define _SYSLOGGER_H
+
+#include <limits.h>				/* for PIPE_BUF */
+
+
+/*
+ * Primitive protocol structure for writing to syslogger pipe(s).  The idea
+ * here is to divide long messages into chunks that are not more than
+ * PIPE_BUF bytes long, which according to POSIX spec must be written into
+ * the pipe atomically.  The pipe reader then uses the protocol headers to
+ * reassemble the parts of a message into a single string.  The reader can
+ * also cope with non-protocol data coming down the pipe, though we cannot
+ * guarantee long strings won't get split apart.
+ *
+ * We use non-nul bytes in is_last to make the protocol a tiny bit
+ * more robust against finding a false double nul byte prologue. But
+ * we still might find it in the len and/or pid bytes unless we're careful.
+ */
+
+#ifdef PIPE_BUF
+/* Are there any systems with PIPE_BUF > 64K?  Unlikely, but ... */
+#if PIPE_BUF > 65536
+#define PIPE_CHUNK_SIZE  65536
+#else
+#define PIPE_CHUNK_SIZE  ((int) PIPE_BUF)
+#endif
+#else							/* not defined */
+/* POSIX says the value of PIPE_BUF must be at least 512, so use that */
+#define PIPE_CHUNK_SIZE  512
+#endif
+
+typedef struct
+{
+	char		nuls[2];		/* always \0\0 */
+	uint16		len;			/* size of this chunk (counts data only) */
+	int32		pid;			/* writer's pid */
+	char		is_last;		/* last chunk of message? 't' or 'f' ('T' or
+								 * 'F' for CSV case) */
+	char		data[FLEXIBLE_ARRAY_MEMBER];	/* data payload starts here */
+} PipeProtoHeader;
+
+typedef union
+{
+	PipeProtoHeader proto;
+	char		filler[PIPE_CHUNK_SIZE];
+} PipeProtoChunk;
+
+#define PIPE_HEADER_SIZE  offsetof(PipeProtoHeader, data)
+#define PIPE_MAX_PAYLOAD  ((int) (PIPE_CHUNK_SIZE - PIPE_HEADER_SIZE))
+
+
+/* GUC options */
+extern bool Logging_collector;
+extern int	Log_RotationAge;
+extern int	Log_RotationSize;
+extern PGDLLIMPORT char *Log_directory;
+extern PGDLLIMPORT char *Log_filename;
+extern bool Log_truncate_on_rotation;
+extern int	Log_file_mode;
+
+#ifndef WIN32
+extern int	syslogPipe[2];
+#else
+extern HANDLE syslogPipe[2];
+#endif
+
+
+extern int	SysLogger_Start(void);
+
+extern void write_syslogger_file(const char *buffer, int count, int dest);
+
+#ifdef EXEC_BACKEND
+extern void SysLoggerMain(int argc, char *argv[]) pg_attribute_noreturn();
+#endif
+
+extern bool CheckLogrotateSignal(void);
+extern void RemoveLogrotateSignalFiles(void);
+
+/*
+ * Name of files saving meta-data information about the log
+ * files currently in use by the syslogger
+ */
+#define LOG_METAINFO_DATAFILE  "current_logfiles"
+#define LOG_METAINFO_DATAFILE_TMP  LOG_METAINFO_DATAFILE ".tmp"
+
+#endif							/* _SYSLOGGER_H */
diff --git a/src/include/postmaster/walwriter.h b/src/include/postmaster/walwriter.h
new file mode 100644
index 0000000..3ccc332
--- /dev/null
+++ b/src/include/postmaster/walwriter.h
@@ -0,0 +1,21 @@
+/*-------------------------------------------------------------------------
+ *
+ * walwriter.h
+ *	  Exports from postmaster/walwriter.c.
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ *
+ * src/include/postmaster/walwriter.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef _WALWRITER_H
+#define _WALWRITER_H
+
+/* GUC options */
+extern int	WalWriterDelay;
+extern int	WalWriterFlushAfter;
+
+extern void WalWriterMain(void) pg_attribute_noreturn();
+
+#endif							/* _WALWRITER_H */