Refactor xlog.c to create src/backend/postmaster/startup.c

Startup process now has its own dedicated file, just like all other
special/background processes. Reduces role and size of xlog.c

src/backend/access/transam/xlog.c

@@ -41,6 +41,7 @@
 #include "miscadmin.h"
 #include "pgstat.h"
 #include "postmaster/bgwriter.h"
+#include "postmaster/startup.h"
 #include "replication/walreceiver.h"
 #include "replication/walsender.h"
 #include "storage/bufmgr.h"
@@ -584,19 +585,6 @@ typedef struct xl_restore_point
 	char		rp_name[MAXFNAMELEN];
 } xl_restore_point;
 
-/*
- * Flags set by interrupt handlers for later service in the redo loop.
- */
-static volatile sig_atomic_t got_SIGHUP = false;
-static volatile sig_atomic_t shutdown_requested = false;
-static volatile sig_atomic_t promote_triggered = false;
-
-/*
- * Flag set when executing a restore command, to tell SIGTERM signal handler
- * that it's safe to just proc_exit.
- */
-static volatile sig_atomic_t in_restore_command = false;
-
 
 static void XLogArchiveNotify(const char *xlog);
 static void XLogArchiveNotifySeg(uint32 log, uint32 seg);
@@ -3068,21 +3056,16 @@ RestoreArchivedFile(char *path, const char *xlogfname,
 							 xlogRestoreCmd)));
 
 	/*
-	 * Set in_restore_command to tell the signal handler that we should exit
+	 * Check signals before restore command and reset afterwards.
-	 * right away on SIGTERM. We know that we're at a safe point to do that.
-	 * Check if we had already received the signal, so that we don't miss a
-	 * shutdown request received just before this.
 	 */
-	in_restore_command = true;
+	PreRestoreCommand();
-	if (shutdown_requested)
-		proc_exit(1);
 
 	/*
 	 * Copy xlog from archival storage to XLOGDIR
 	 */
 	rc = system(xlogRestoreCmd);
 
-	in_restore_command = false;
+	PostRestoreCommand();
 
 	if (rc == 0)
 	{
@@ -9946,177 +9929,6 @@ CancelBackup(void)
 	}
 }
 
-/* ------------------------------------------------------
- *	Startup Process main entry point and signal handlers
- * ------------------------------------------------------
- */
-
-/*
- * startupproc_quickdie() occurs when signalled SIGQUIT by the postmaster.
- *
- * Some backend has bought the farm,
- * so we need to stop what we're doing and exit.
- */
-static void
-startupproc_quickdie(SIGNAL_ARGS)
-{
-	PG_SETMASK(&BlockSig);
-
-	/*
-	 * We DO NOT want to run proc_exit() callbacks -- we're here because
-	 * shared memory may be corrupted, so we don't want to try to clean up our
-	 * transaction.  Just nail the windows shut and get out of town.  Now that
-	 * there's an atexit callback to prevent third-party code from breaking
-	 * things by calling exit() directly, we have to reset the callbacks
-	 * explicitly to make this work as intended.
-	 */
-	on_exit_reset();
-
-	/*
-	 * Note we do exit(2) not exit(0).	This is to force the postmaster into a
-	 * system reset cycle if some idiot DBA sends a manual SIGQUIT to a random
-	 * backend.  This is necessary precisely because we don't clean up our
-	 * shared memory state.  (The "dead man switch" mechanism in pmsignal.c
-	 * should ensure the postmaster sees this as a crash, too, but no harm in
-	 * being doubly sure.)
-	 */
-	exit(2);
-}
-
-
-/* SIGUSR1: let latch facility handle the signal */
-static void
-StartupProcSigUsr1Handler(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	latch_sigusr1_handler();
-
-	errno = save_errno;
-}
-
-/* SIGUSR2: set flag to finish recovery */
-static void
-StartupProcTriggerHandler(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	promote_triggered = true;
-	WakeupRecovery();
-
-	errno = save_errno;
-}
-
-/* SIGHUP: set flag to re-read config file at next convenient time */
-static void
-StartupProcSigHupHandler(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	got_SIGHUP = true;
-	WakeupRecovery();
-
-	errno = save_errno;
-}
-
-/* SIGTERM: set flag to abort redo and exit */
-static void
-StartupProcShutdownHandler(SIGNAL_ARGS)
-{
-	int			save_errno = errno;
-
-	if (in_restore_command)
-		proc_exit(1);
-	else
-		shutdown_requested = true;
-	WakeupRecovery();
-
-	errno = save_errno;
-}
-
-/* Handle SIGHUP and SIGTERM signals of startup process */
-void
-HandleStartupProcInterrupts(void)
-{
-	/*
-	 * Check if we were requested to re-read config file.
-	 */
-	if (got_SIGHUP)
-	{
-		got_SIGHUP = false;
-		ProcessConfigFile(PGC_SIGHUP);
-	}
-
-	/*
-	 * Check if we were requested to exit without finishing recovery.
-	 */
-	if (shutdown_requested)
-		proc_exit(1);
-
-	/*
-	 * Emergency bailout if postmaster has died.  This is to avoid the
-	 * necessity for manual cleanup of all postmaster children.
-	 */
-	if (IsUnderPostmaster && !PostmasterIsAlive())
-		exit(1);
-}
-
-/* Main entry point for startup process */
-void
-StartupProcessMain(void)
-{
-	/*
-	 * If possible, make this process a group leader, so that the postmaster
-	 * can signal any child processes too.
-	 */
-#ifdef HAVE_SETSID
-	if (setsid() < 0)
-		elog(FATAL, "setsid() failed: %m");
-#endif
-
-	/*
-	 * Properly accept or ignore signals the postmaster might send us.
-	 *
-	 * Note: ideally we'd not enable handle_standby_sig_alarm unless actually
-	 * doing hot standby, but we don't know that yet.  Rely on it to not do
-	 * anything if it shouldn't.
-	 */
-	pqsignal(SIGHUP, StartupProcSigHupHandler); /* reload config file */
-	pqsignal(SIGINT, SIG_IGN);	/* ignore query cancel */
-	pqsignal(SIGTERM, StartupProcShutdownHandler);		/* request shutdown */
-	pqsignal(SIGQUIT, startupproc_quickdie);	/* hard crash time */
-	if (EnableHotStandby)
-		pqsignal(SIGALRM, handle_standby_sig_alarm);	/* ignored unless
-														 * InHotStandby */
-	else
-		pqsignal(SIGALRM, SIG_IGN);
-	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, StartupProcSigUsr1Handler);
-	pqsignal(SIGUSR2, StartupProcTriggerHandler);
-
-	/*
-	 * Reset some signals that are accepted by postmaster but not here
-	 */
-	pqsignal(SIGCHLD, SIG_DFL);
-	pqsignal(SIGTTIN, SIG_DFL);
-	pqsignal(SIGTTOU, SIG_DFL);
-	pqsignal(SIGCONT, SIG_DFL);
-	pqsignal(SIGWINCH, SIG_DFL);
-
-	/*
-	 * Unblock signals (they were blocked when the postmaster forked us)
-	 */
-	PG_SETMASK(&UnBlockSig);
-
-	StartupXLOG();
-
-	/*
-	 * Exit normally. Exit code 0 tells postmaster that we completed recovery
-	 * successfully.
-	 */
-	proc_exit(0);
-}
-
 /*
  * Read the XLOG page containing RecPtr into readBuf (if not read already).
  * Returns true if the page is read successfully.
@@ -10564,12 +10376,12 @@ CheckForStandbyTrigger(void)
 	if (triggered)
 		return true;
 
-	if (promote_triggered)
+	if (IsPromoteTriggered())
 	{
 		ereport(LOG,
 				(errmsg("received promote request")));
 		ShutdownWalRcv();
-		promote_triggered = false;
+		ResetPromoteTriggered();
 		triggered = true;
 		return true;
 	}

src/backend/bootstrap/bootstrap.c

@@ -29,6 +29,7 @@
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
 #include "postmaster/bgwriter.h"
+#include "postmaster/startup.h"
 #include "postmaster/walwriter.h"
 #include "replication/walreceiver.h"
 #include "storage/bufmgr.h"

src/backend/postmaster/Makefile

@@ -13,6 +13,6 @@ top_builddir = ../../..
 include $(top_builddir)/src/Makefile.global
 
 OBJS = autovacuum.o bgwriter.o fork_process.o pgarch.o pgstat.o postmaster.o \
-	syslogger.o walwriter.o checkpointer.o
+	startup.o syslogger.o walwriter.o checkpointer.o
 
 include $(top_srcdir)/src/backend/common.mk

src/backend/postmaster/startup.c

@@ -0,0 +1,259 @@
+/*-------------------------------------------------------------------------
+ *
+ * startup.c
+ *
+ * The Startup process initialises the server and performs any recovery
+ * actions that have been specified. Notice that there is no "main loop"
+ * since the Startup process ends as soon as initialisation is complete.
+ *
+ *
+ * Portions Copyright (c) 1996-2011, PostgreSQL Global Development Group
+ *
+ *
+ * IDENTIFICATION
+ *	  src/backend/postmaster/startup.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include <signal.h>
+#include <unistd.h>
+
+#include "access/xlog.h"
+#include "libpq/pqsignal.h"
+#include "miscadmin.h"
+#include "postmaster/startup.h"
+#include "storage/ipc.h"
+#include "storage/latch.h"
+#include "storage/pmsignal.h"
+#include "storage/proc.h"
+#include "utils/guc.h"
+
+
+/*
+ * Flags set by interrupt handlers for later service in the redo loop.
+ */
+static volatile sig_atomic_t got_SIGHUP = false;
+static volatile sig_atomic_t shutdown_requested = false;
+static volatile sig_atomic_t promote_triggered = false;
+
+/*
+ * Flag set when executing a restore command, to tell SIGTERM signal handler
+ * that it's safe to just proc_exit.
+ */
+static volatile sig_atomic_t in_restore_command = false;
+
+/* Signal handlers */
+static void startupproc_quickdie(SIGNAL_ARGS);
+static void StartupProcSigUsr1Handler(SIGNAL_ARGS);
+static void StartupProcTriggerHandler(SIGNAL_ARGS);
+static void StartupProcSigHupHandler(SIGNAL_ARGS);
+
+
+/* --------------------------------
+ *		signal handler routines
+ * --------------------------------
+ */
+
+/*
+ * startupproc_quickdie() occurs when signalled SIGQUIT by the postmaster.
+ *
+ * Some backend has bought the farm,
+ * so we need to stop what we're doing and exit.
+ */
+static void
+startupproc_quickdie(SIGNAL_ARGS)
+{
+	PG_SETMASK(&BlockSig);
+
+	/*
+	 * We DO NOT want to run proc_exit() callbacks -- we're here because
+	 * shared memory may be corrupted, so we don't want to try to clean up our
+	 * transaction.  Just nail the windows shut and get out of town.  Now that
+	 * there's an atexit callback to prevent third-party code from breaking
+	 * things by calling exit() directly, we have to reset the callbacks
+	 * explicitly to make this work as intended.
+	 */
+	on_exit_reset();
+
+	/*
+	 * Note we do exit(2) not exit(0).	This is to force the postmaster into a
+	 * system reset cycle if some idiot DBA sends a manual SIGQUIT to a random
+	 * backend.  This is necessary precisely because we don't clean up our
+	 * shared memory state.  (The "dead man switch" mechanism in pmsignal.c
+	 * should ensure the postmaster sees this as a crash, too, but no harm in
+	 * being doubly sure.)
+	 */
+	exit(2);
+}
+
+
+/* SIGUSR1: let latch facility handle the signal */
+static void
+StartupProcSigUsr1Handler(SIGNAL_ARGS)
+{
+	int			save_errno = errno;
+
+	latch_sigusr1_handler();
+
+	errno = save_errno;
+}
+
+/* SIGUSR2: set flag to finish recovery */
+static void
+StartupProcTriggerHandler(SIGNAL_ARGS)
+{
+	int			save_errno = errno;
+
+	promote_triggered = true;
+	WakeupRecovery();
+
+	errno = save_errno;
+}
+
+/* SIGHUP: set flag to re-read config file at next convenient time */
+static void
+StartupProcSigHupHandler(SIGNAL_ARGS)
+{
+	int			save_errno = errno;
+
+	got_SIGHUP = true;
+	WakeupRecovery();
+
+	errno = save_errno;
+}
+
+/* SIGTERM: set flag to abort redo and exit */
+static void
+StartupProcShutdownHandler(SIGNAL_ARGS)
+{
+	int			save_errno = errno;
+
+	if (in_restore_command)
+		proc_exit(1);
+	else
+		shutdown_requested = true;
+	WakeupRecovery();
+
+	errno = save_errno;
+}
+
+/* Handle SIGHUP and SIGTERM signals of startup process */
+void
+HandleStartupProcInterrupts(void)
+{
+	/*
+	 * Check if we were requested to re-read config file.
+	 */
+	if (got_SIGHUP)
+	{
+		got_SIGHUP = false;
+		ProcessConfigFile(PGC_SIGHUP);
+	}
+
+	/*
+	 * Check if we were requested to exit without finishing recovery.
+	 */
+	if (shutdown_requested)
+		proc_exit(1);
+
+	/*
+	 * Emergency bailout if postmaster has died.  This is to avoid the
+	 * necessity for manual cleanup of all postmaster children.
+	 */
+	if (IsUnderPostmaster && !PostmasterIsAlive())
+		exit(1);
+}
+
+
+/* ----------------------------------
+ *	Startup Process main entry point
+ * ----------------------------------
+ */
+void
+StartupProcessMain(void)
+{
+	/*
+	 * If possible, make this process a group leader, so that the postmaster
+	 * can signal any child processes too.
+	 */
+#ifdef HAVE_SETSID
+	if (setsid() < 0)
+		elog(FATAL, "setsid() failed: %m");
+#endif
+
+	/*
+	 * Properly accept or ignore signals the postmaster might send us.
+	 *
+	 * Note: ideally we'd not enable handle_standby_sig_alarm unless actually
+	 * doing hot standby, but we don't know that yet.  Rely on it to not do
+	 * anything if it shouldn't.
+	 */
+	pqsignal(SIGHUP, StartupProcSigHupHandler); /* reload config file */
+	pqsignal(SIGINT, SIG_IGN);	/* ignore query cancel */
+	pqsignal(SIGTERM, StartupProcShutdownHandler);		/* request shutdown */
+	pqsignal(SIGQUIT, startupproc_quickdie);	/* hard crash time */
+	if (EnableHotStandby)
+		pqsignal(SIGALRM, handle_standby_sig_alarm);	/* ignored unless
+														 * InHotStandby */
+	else
+		pqsignal(SIGALRM, SIG_IGN);
+	pqsignal(SIGPIPE, SIG_IGN);
+	pqsignal(SIGUSR1, StartupProcSigUsr1Handler);
+	pqsignal(SIGUSR2, StartupProcTriggerHandler);
+
+	/*
+	 * Reset some signals that are accepted by postmaster but not here
+	 */
+	pqsignal(SIGCHLD, SIG_DFL);
+	pqsignal(SIGTTIN, SIG_DFL);
+	pqsignal(SIGTTOU, SIG_DFL);
+	pqsignal(SIGCONT, SIG_DFL);
+	pqsignal(SIGWINCH, SIG_DFL);
+
+	/*
+	 * Unblock signals (they were blocked when the postmaster forked us)
+	 */
+	PG_SETMASK(&UnBlockSig);
+
+	StartupXLOG();
+
+	/*
+	 * Exit normally. Exit code 0 tells postmaster that we completed recovery
+	 * successfully.
+	 */
+	proc_exit(0);
+}
+
+void
+PreRestoreCommand(void)
+{
+	/*
+	 * Set in_restore_command to tell the signal handler that we should exit
+	 * right away on SIGTERM. We know that we're at a safe point to do that.
+	 * Check if we had already received the signal, so that we don't miss a
+	 * shutdown request received just before this.
+	 */
+	in_restore_command = true;
+	if (shutdown_requested)
+		proc_exit(1);
+}
+
+void
+PostRestoreCommand(void)
+{
+	in_restore_command = false;
+}
+
+bool
+IsPromoteTriggered(void)
+{
+	return promote_triggered;
+}
+
+void
+ResetPromoteTriggered(void)
+{
+	promote_triggered = false;
+}

src/backend/replication/walreceiverfuncs.c

@@ -24,6 +24,7 @@
 #include <signal.h>
 
 #include "access/xlog_internal.h"
+#include "postmaster/startup.h"
 #include "replication/walreceiver.h"
 #include "storage/pmsignal.h"
 #include "storage/shmem.h"
@@ -110,6 +111,7 @@ WalRcvInProgress(void)
 
 /*
  * Stop walreceiver (if running) and wait for it to die.
+ * Executed by the Startup process.
  */
 void
 ShutdownWalRcv(void)

src/include/access/xlog.h

@@ -312,8 +312,6 @@ extern XLogRecPtr GetFlushRecPtr(void);
 extern void GetNextXidAndEpoch(TransactionId *xid, uint32 *epoch);
 extern TimeLineID GetRecoveryTargetTLI(void);
 
-extern void HandleStartupProcInterrupts(void);
-extern void StartupProcessMain(void);
 extern bool CheckPromoteSignal(void);
 extern void WakeupRecovery(void);
 

src/include/postmaster/startup.h

@@ -0,0 +1,22 @@
+/*-------------------------------------------------------------------------
+ *
+ * startup.h
+ *	  Exports from postmaster/startup.c.
+ *
+ * Portions Copyright (c) 1996-2011, PostgreSQL Global Development Group
+ *
+ * src/include/postmaster/startup.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef _STARTUP_H
+#define _STARTUP_H
+
+extern void HandleStartupProcInterrupts(void);
+extern void StartupProcessMain(void);
+extern void PreRestoreCommand(void);
+extern void PostRestoreCommand(void);
+extern bool IsPromoteTriggered(void);
+extern void ResetPromoteTriggered(void);
+
+#endif   /* _STARTUP_H */