Function sigusr1_handler

src/backend/postmaster/postmaster.c:5738–5964

* sigusr1_handler - handle signal conditions from child processes */

 * sigusr1_handler - handle signal conditions from child processes
 */
static void
sigusr1_handler(SIGNAL_ARGS)
{
	int			save_errno = errno;

	/*
	 * RECOVERY_STARTED and BEGIN_HOT_STANDBY signals are ignored in
	 * unexpected states. If the startup process quickly starts up, completes
	 * recovery, exits, we might process the death of the startup process
	 * first. We don't want to go back to recovery in that case.
	 */
	if (CheckPostmasterSignal(PMSIGNAL_RECOVERY_STARTED) &&
		pmState == PM_STARTUP && Shutdown == NoShutdown)
	{
		/* WAL redo has started. We're out of reinitialization. */
		bool		promotion_requested = false;

		FatalError = false;
		AbortStartTime = 0;

		/*
		 * Crank up the background tasks.  It doesn't matter if this fails,
		 * we'll just try again later.
		 */
		Assert(CheckpointerPID == 0);
		CheckpointerPID = StartCheckpointer();
		Assert(BgWriterPID == 0);
		BgWriterPID = StartBackgroundWriter();

		/*
		 * Start the archiver if we're responsible for (re-)archiving received
		 * files.
		 */
		Assert(PgArchPID == 0);
		if (XLogArchivingAlways())
			PgArchPID = StartArchiver();

		/*
		 * GPDB: if promote trigger file exist we don't wish to convey
		 * PM_STATUS_STANDBY, instead wish pg_ctl -w to wait till
		 * connections can be actually accepted by the database.
		 */
		if (PromoteTriggerFile != NULL && strcmp(PromoteTriggerFile, "") != 0)
		{
			struct stat stat_buf;

			if (stat(PromoteTriggerFile, &stat_buf) == 0)
				promotion_requested = true;
		}
		/*
		 * GPDB: Setting recovery_target_action
		 * configuration parameter to 'promote' will also result
		 * into promotion after recovery is completed.
		 */
		if (recoveryTargetAction == RECOVERY_TARGET_ACTION_PROMOTE)
			promotion_requested = true;

		/*