/*
 * get_postmaster_pid()
 *
 * Returns the pid of the postmaster running on datadir. pid is retrieved
 * from the postmaster.pid file
 */
static pgpid_t
get_postmaster_pid(const char *datadir)
{
	FILE	   *pidf;
	long		pid;
	char		pid_file[MAXPGPATH];

	snprintf(pid_file, sizeof(pid_file), "%s/postmaster.pid", datadir);
	pidf = fopen(pid_file, "r");

	if (pidf == NULL)
		return (pgpid_t) 0;

	if (fscanf(pidf, "%ld", &pid) != 1)
	{
		fclose(pidf);
		pg_log(PG_FATAL, "%s: invalid data in PID file \"%s\"\n",
			   os_info.progname, pid_file);
	}

	fclose(pidf);

	return (pgpid_t) pid;
}

void
output_check_banner(bool *live_check)
{
	if (user_opts.check && is_server_running(old_cluster.pgdata))
	{
		*live_check = true;
		if (old_cluster.port == DEF_PGUPORT)
			pg_log(PG_FATAL, "When checking a live old server, "
				   "you must specify the old server's port number.\n");
		if (old_cluster.port == new_cluster.port)
			pg_log(PG_FATAL, "When checking a live server, "
				   "the old and new port numbers must be different.\n");
		pg_log(PG_REPORT, "Performing Consistency Checks on Old Live Server\n");
		pg_log(PG_REPORT, "------------------------------------------------\n");
	}
	else
	{
		pg_log(PG_REPORT, "Performing Consistency Checks\n");
		pg_log(PG_REPORT, "-----------------------------\n");
	}
}

static void
create_new_objects(void)
{
	int			dbnum;

	prep_status("Restoring database schemas in the new cluster\n");

	/*
	 * We cannot process the template1 database concurrently with others,
	 * because when it's transiently dropped, connection attempts would fail.
	 * So handle it in a separate non-parallelized pass.
	 */
	for (dbnum = 0; dbnum < old_cluster.dbarr.ndbs; dbnum++)
	{
		char		sql_file_name[MAXPGPATH],
					log_file_name[MAXPGPATH];
		DbInfo	   *old_db = &old_cluster.dbarr.dbs[dbnum];
		const char *create_opts;

		/* Process only template1 in this pass */
		if (strcmp(old_db->db_name, "template1") != 0)
			continue;

		pg_log(PG_STATUS, "%s", old_db->db_name);
		snprintf(sql_file_name, sizeof(sql_file_name), DB_DUMP_FILE_MASK, old_db->db_oid);
		snprintf(log_file_name, sizeof(log_file_name), DB_DUMP_LOG_FILE_MASK, old_db->db_oid);

		/*
		 * template1 and postgres databases will already exist in the target
		 * installation, so tell pg_restore to drop and recreate them;
		 * otherwise we would fail to propagate their database-level
		 * properties.
		 */
		create_opts = "--clean --create";

		exec_prog(log_file_name,
				  NULL,
				  true,
				  true,
				  "\"%s/pg_restore\" %s %s --exit-on-error --verbose "
				  "--dbname postgres \"%s\"",
				  new_cluster.bindir,
				  cluster_conn_opts(&new_cluster),
				  create_opts,
				  sql_file_name);

		break;					/* done once we've processed template1 */
	}

	for (dbnum = 0; dbnum < old_cluster.dbarr.ndbs; dbnum++)
	{
		char		sql_file_name[MAXPGPATH],
					log_file_name[MAXPGPATH];
		DbInfo	   *old_db = &old_cluster.dbarr.dbs[dbnum];
		const char *create_opts;

		/* Skip template1 in this pass */
		if (strcmp(old_db->db_name, "template1") == 0)
			continue;

		pg_log(PG_STATUS, "%s", old_db->db_name);
		snprintf(sql_file_name, sizeof(sql_file_name), DB_DUMP_FILE_MASK, old_db->db_oid);
		snprintf(log_file_name, sizeof(log_file_name), DB_DUMP_LOG_FILE_MASK, old_db->db_oid);

		/*
		 * template1 and postgres databases will already exist in the target
		 * installation, so tell pg_restore to drop and recreate them;
		 * otherwise we would fail to propagate their database-level
		 * properties.
		 */
		if (strcmp(old_db->db_name, "postgres") == 0)
			create_opts = "--clean --create";
		else
			create_opts = "--create";

		parallel_exec_prog(log_file_name,
						   NULL,
						   "\"%s/pg_restore\" %s %s --exit-on-error --verbose "
						   "--dbname template1 \"%s\"",
						   new_cluster.bindir,
						   cluster_conn_opts(&new_cluster),
						   create_opts,
						   sql_file_name);
	}

	/* reap all children */
	while (reap_child(true) == true)
		;

	end_progress_output();
	check_ok();

	/*
	 * We don't have minmxids for databases or relations in pre-9.3 clusters,
	 * so set those after we have restored the schema.
	 */
	if (GET_MAJOR_VERSION(old_cluster.major_version) < 903)
		set_frozenxids(true);

	/* update new_cluster info now that we have objects in the databases */
//.........这里部分代码省略.........

/*----
 * Runs a query, which returns pieces of files from the remote source data
 * directory, and overwrites the corresponding parts of target files with
 * the received parts. The result set is expected to be of format:
 *
 * path		text	-- path in the data directory, e.g "base/1/123"
 * begin	int8	-- offset within the file
 * chunk	bytea	-- file content
 *----
 */
static void
receiveFileChunks(const char *sql)
{
	PGresult   *res;

	if (PQsendQueryParams(conn, sql, 0, NULL, NULL, NULL, NULL, 1) != 1)
		pg_fatal("could not send query: %s", PQerrorMessage(conn));

	pg_log(PG_DEBUG, "getting file chunks\n");

	if (PQsetSingleRowMode(conn) != 1)
		pg_fatal("could not set libpq connection to single row mode\n");

	while ((res = PQgetResult(conn)) != NULL)
	{
		char	   *filename;
		int			filenamelen;
		int64		chunkoff;
		char		chunkoff_str[32];
		int			chunksize;
		char	   *chunk;

		switch (PQresultStatus(res))
		{
			case PGRES_SINGLE_TUPLE:
				break;

			case PGRES_TUPLES_OK:
				PQclear(res);
				continue;		/* final zero-row result */

			default:
				pg_fatal("unexpected result while fetching remote files: %s",
						 PQresultErrorMessage(res));
		}

		/* sanity check the result set */
		if (PQnfields(res) != 3 || PQntuples(res) != 1)
			pg_fatal("unexpected result set size while fetching remote files\n");

		if (PQftype(res, 0) != TEXTOID ||
			PQftype(res, 1) != INT8OID ||
			PQftype(res, 2) != BYTEAOID)
		{
			pg_fatal("unexpected data types in result set while fetching remote files: %u %u %u\n",
					 PQftype(res, 0), PQftype(res, 1), PQftype(res, 2));
		}

		if (PQfformat(res, 0) != 1 &&
			PQfformat(res, 1) != 1 &&
			PQfformat(res, 2) != 1)
		{
			pg_fatal("unexpected result format while fetching remote files\n");
		}

		if (PQgetisnull(res, 0, 0) ||
			PQgetisnull(res, 0, 1))
		{
			pg_fatal("unexpected null values in result while fetching remote files\n");
		}

		if (PQgetlength(res, 0, 1) != sizeof(int64))
			pg_fatal("unexpected result length while fetching remote files\n");

		/* Read result set to local variables */
		memcpy(&chunkoff, PQgetvalue(res, 0, 1), sizeof(int64));
		chunkoff = pg_recvint64(chunkoff);
		chunksize = PQgetlength(res, 0, 2);

		filenamelen = PQgetlength(res, 0, 0);
		filename = pg_malloc(filenamelen + 1);
		memcpy(filename, PQgetvalue(res, 0, 0), filenamelen);
		filename[filenamelen] = '\0';

		chunk = PQgetvalue(res, 0, 2);

		/*
		 * If a file has been deleted on the source, remove it on the target
		 * as well.  Note that multiple unlink() calls may happen on the same
		 * file if multiple data chunks are associated with it, hence ignore
		 * unconditionally anything missing.  If this file is not a relation
		 * data file, then it has been already truncated when creating the
		 * file chunk list at the previous execution of the filemap.
		 */
		if (PQgetisnull(res, 0, 2))
		{
			pg_log(PG_DEBUG,
				   "received null value for chunk for file \"%s\", file has been deleted\n",
				   filename);
			remove_target_file(filename, true);
//.........这里部分代码省略.........

/*
 * check_for_reg_data_type_usage()
 *	pg_upgrade only preserves these system values:
 *		pg_class.oid
 *		pg_type.oid
 *		pg_enum.oid
 *
 *	Many of the reg* data types reference system catalog info that is
 *	not preserved, and hence these data types cannot be used in user
 *	tables upgraded by pg_upgrade.
 */
static void
check_for_reg_data_type_usage(ClusterInfo *cluster)
{
	int			dbnum;
	FILE	   *script = NULL;
	bool		found = false;
	char		output_path[MAXPGPATH];

	prep_status("Checking for reg* system OID user data types");

	snprintf(output_path, sizeof(output_path), "tables_using_reg.txt");

	for (dbnum = 0; dbnum < cluster->dbarr.ndbs; dbnum++)
	{
		PGresult   *res;
		bool		db_used = false;
		int			ntups;
		int			rowno;
		int			i_nspname,
					i_relname,
					i_attname;
		DbInfo	   *active_db = &cluster->dbarr.dbs[dbnum];
		PGconn	   *conn = connectToServer(cluster, active_db->db_name);

		/*
		 * While several relkinds don't store any data, e.g. views, they can
		 * be used to define data types of other columns, so we check all
		 * relkinds.
		 */
		res = executeQueryOrDie(conn,
								"SELECT n.nspname, c.relname, a.attname "
								"FROM	pg_catalog.pg_class c, "
								"		pg_catalog.pg_namespace n, "
								"		pg_catalog.pg_attribute a "
								"WHERE	c.oid = a.attrelid AND "
								"		NOT a.attisdropped AND "
								"		a.atttypid IN ( "
		  "			'pg_catalog.regproc'::pg_catalog.regtype, "
								"			'pg_catalog.regprocedure'::pg_catalog.regtype, "
		  "			'pg_catalog.regoper'::pg_catalog.regtype, "
								"			'pg_catalog.regoperator'::pg_catalog.regtype, "
		/* regclass.oid is preserved, so 'regclass' is OK */
		/* regtype.oid is preserved, so 'regtype' is OK */
		"			'pg_catalog.regconfig'::pg_catalog.regtype, "
								"			'pg_catalog.regdictionary'::pg_catalog.regtype) AND "
								"		c.relnamespace = n.oid AND "
							  "		n.nspname NOT IN ('pg_catalog', 'information_schema')");

		ntups = PQntuples(res);
		i_nspname = PQfnumber(res, "nspname");
		i_relname = PQfnumber(res, "relname");
		i_attname = PQfnumber(res, "attname");
		for (rowno = 0; rowno < ntups; rowno++)
		{
			found = true;
			if (script == NULL && (script = fopen_priv(output_path, "w")) == NULL)
				pg_fatal("Could not open file \"%s\": %s\n",
						 output_path, getErrorText(errno));
			if (!db_used)
			{
				fprintf(script, "Database: %s\n", active_db->db_name);
				db_used = true;
			}
			fprintf(script, "  %s.%s.%s\n",
					PQgetvalue(res, rowno, i_nspname),
					PQgetvalue(res, rowno, i_relname),
					PQgetvalue(res, rowno, i_attname));
		}

		PQclear(res);

		PQfinish(conn);
	}

	if (script)
		fclose(script);

	if (found)
	{
		pg_log(PG_REPORT, "fatal\n");
		pg_fatal("Your installation contains one of the reg* data types in user tables.\n"
		 "These data types reference system OIDs that are not preserved by\n"
		"pg_upgrade, so this cluster cannot currently be upgraded.  You can\n"
				 "remove the problem tables and restart the upgrade.  A list of the problem\n"
				 "columns is in the file:\n"
				 "    %s\n\n", output_path);
	}
	else
		check_ok();
//.........这里部分代码省略.........

/*
 * get_sock_dir
 *
 * Identify the socket directory to use for this cluster.  If we're doing
 * a live check (old cluster only), we need to find out where the postmaster
 * is listening.  Otherwise, we're going to put the socket into the current
 * directory.
 */
void
get_sock_dir(ClusterInfo *cluster, bool live_check)
{
#ifdef HAVE_UNIX_SOCKETS

	/*
	 * sockdir and port were added to postmaster.pid in PG 9.1. Pre-9.1 cannot
	 * process pg_ctl -w for sockets in non-default locations.
	 */
	if (GET_MAJOR_VERSION(cluster->major_version) >= 901)
	{
		if (!live_check)
		{
			/* Use the current directory for the socket */
			cluster->sockdir = pg_malloc(MAXPGPATH);
			if (!getcwd(cluster->sockdir, MAXPGPATH))
				pg_fatal("cannot find current directory\n");
		}
		else
		{
			/*
			 * If we are doing a live check, we will use the old cluster's
			 * Unix domain socket directory so we can connect to the live
			 * server.
			 */
			unsigned short orig_port = cluster->port;
			char		filename[MAXPGPATH],
						line[MAXPGPATH];
			FILE	   *fp;
			int			lineno;

			snprintf(filename, sizeof(filename), "%s/postmaster.pid",
					 cluster->pgdata);
			if ((fp = fopen(filename, "r")) == NULL)
				pg_fatal("Cannot open file %s: %m\n", filename);

			for (lineno = 1;
			   lineno <= Max(LOCK_FILE_LINE_PORT, LOCK_FILE_LINE_SOCKET_DIR);
				 lineno++)
			{
				if (fgets(line, sizeof(line), fp) == NULL)
					pg_fatal("Cannot read line %d from %s: %m\n", lineno, filename);

				/* potentially overwrite user-supplied value */
				if (lineno == LOCK_FILE_LINE_PORT)
					sscanf(line, "%hu", &old_cluster.port);
				if (lineno == LOCK_FILE_LINE_SOCKET_DIR)
				{
					cluster->sockdir = pg_malloc(MAXPGPATH);
					/* strip off newline */
					sscanf(line, "%s\n", cluster->sockdir);
				}
			}
			fclose(fp);

			/* warn of port number correction */
			if (orig_port != DEF_PGUPORT && old_cluster.port != orig_port)
				pg_log(PG_WARNING, "User-supplied old port number %hu corrected to %hu\n",
					   orig_port, cluster->port);
		}
	}
	else

		/*
		 * Can't get sockdir and pg_ctl -w can't use a non-default, use
		 * default
		 */
		cluster->sockdir = NULL;
#else							/* !HAVE_UNIX_SOCKETS */
	cluster->sockdir = NULL;
#endif
}

/*
 * old_8_3_create_sequence_script()
 *	8.3 -> 8.4
 *	8.4 added the column "start_value" to all sequences.  For this reason,
 *	we don't transfer sequence files but instead use the CREATE SEQUENCE
 *	command from the schema dump, and use setval() to restore the sequence
 *	value and 'is_called' from the old database.  This is safe to run
 *	by pg_upgrade because sequence files are not transfered from the old
 *	server, even in link mode.
 */
char *
old_8_3_create_sequence_script(ClusterInfo *cluster)
{
	int			dbnum;
	FILE	   *script = NULL;
	bool		found = false;
	char	   *output_path = pg_malloc(MAX_PG_PATH);

	snprintf(output_path, MAX_PG_PATH, "%s/adjust_sequences.sql", os_info.cwd);

	prep_status("Creating script to adjust sequences");

	for (dbnum = 0; dbnum < cluster->dbarr.ndbs; dbnum++)
	{
		PGresult   *res;
		bool		db_used = false;
		int			ntups;
		int			rowno;
		int			i_nspname,
					i_relname;
		DbInfo	   *active_db = &cluster->dbarr.dbs[dbnum];
		PGconn	   *conn = connectToServer(cluster, active_db->db_name);

		/* Find any sequences */
		res = executeQueryOrDie(conn,
								"SELECT n.nspname, c.relname "
								"FROM	pg_catalog.pg_class c, "
								"		pg_catalog.pg_namespace n "
								"WHERE	c.relkind = 'S' AND "
								"		c.relnamespace = n.oid AND "
								 /* exclude possible orphaned temp tables */
								"  		n.nspname !~ '^pg_temp_' AND "
								"		n.nspname !~ '^pg_toast_temp_' AND "
						 		"		n.nspname NOT IN ('pg_catalog', 'information_schema')");

		ntups = PQntuples(res);
		i_nspname = PQfnumber(res, "nspname");
		i_relname = PQfnumber(res, "relname");
		for (rowno = 0; rowno < ntups; rowno++)
		{
			PGresult   *seq_res;
			int			i_last_value,
						i_is_called;
			const char *nspname = PQgetvalue(res, rowno, i_nspname);
			const char *relname = PQgetvalue(res, rowno, i_relname);

			found = true;

			if (script == NULL && (script = fopen(output_path, "w")) == NULL)
				pg_log(PG_FATAL, "could not create necessary file:  %s\n", output_path);
			if (!db_used)
			{
				fprintf(script, "\\connect %s\n\n",
						quote_identifier(active_db->db_name));
				db_used = true;
			}

			/* Find the desired sequence */
			seq_res = executeQueryOrDie(conn,
										"SELECT s.last_value, s.is_called "
										"FROM	%s.%s s",
										quote_identifier(nspname),
										quote_identifier(relname));

			assert(PQntuples(seq_res) == 1);
			i_last_value = PQfnumber(seq_res, "last_value");
			i_is_called = PQfnumber(seq_res, "is_called");

			fprintf(script, "SELECT setval('%s.%s', %s, '%s');\n",
					quote_identifier(nspname), quote_identifier(relname),
					PQgetvalue(seq_res, 0, i_last_value), PQgetvalue(seq_res, 0, i_is_called));
			PQclear(seq_res);
		}
		if (db_used)
			fprintf(script, "\n");

		PQclear(res);

		PQfinish(conn);
	}

	if (script)
		fclose(script);

	check_ok();

	if (found)
		return output_path;
	else
	{
//.........这里部分代码省略.........

/*
 * old_8_3_rebuild_tsvector_tables()
 *	8.3 -> 8.4
 * 8.3 sorts lexemes by its length and if lengths are the same then it uses
 * alphabetic order;  8.4 sorts lexemes in lexicographical order, e.g.
 *
 * => SELECT 'c bb aaa'::tsvector;
 *	   tsvector
 * ----------------
 *	'aaa' 'bb' 'c'		   -- 8.4
 *	'c' 'bb' 'aaa'		   -- 8.3
 */
void
old_8_3_rebuild_tsvector_tables(ClusterInfo *cluster, bool check_mode)
{
	int			dbnum;
	FILE	   *script = NULL;
	bool		found = false;
	char		output_path[MAX_PG_PATH];

	prep_status("Checking for tsvector user columns");

	snprintf(output_path, sizeof(output_path), "%s/rebuild_tsvector_tables.sql",
			 os_info.cwd);

	for (dbnum = 0; dbnum < cluster->dbarr.ndbs; dbnum++)
	{
		PGresult   *res;
		bool		db_used = false;
		char		nspname[NAMEDATALEN] = "",
					relname[NAMEDATALEN] = "";
		int			ntups;
		int			rowno;
		int			i_nspname,
					i_relname,
					i_attname;
		DbInfo	   *active_db = &cluster->dbarr.dbs[dbnum];
		PGconn	   *conn = connectToServer(cluster, active_db->db_name);

		/* Find any user-defined tsvector columns */
		res = executeQueryOrDie(conn,
								"SELECT n.nspname, c.relname, a.attname "
								"FROM	pg_catalog.pg_class c, "
								"		pg_catalog.pg_namespace n, "
								"		pg_catalog.pg_attribute a "
								"WHERE	c.relkind = 'r' AND "
								"		c.oid = a.attrelid AND "
								"		NOT a.attisdropped AND "
								"		a.atttypid = 'pg_catalog.tsvector'::pg_catalog.regtype AND "
								"		c.relnamespace = n.oid AND "
								 /* exclude possible orphaned temp tables */
								"  		n.nspname !~ '^pg_temp_' AND "
								"		n.nspname !~ '^pg_toast_temp_' AND "
						 		"		n.nspname NOT IN ('pg_catalog', 'information_schema')");

/*
 *	This macro is used below to avoid reindexing indexes already rebuilt
 *	because of tsvector columns.
 */
#define SKIP_TSVECTOR_TABLES \
								"i.indrelid NOT IN ( "					\
								"SELECT DISTINCT c.oid "				\
								"FROM	pg_catalog.pg_class c, "		\
								"		pg_catalog.pg_namespace n, "	\
								"		pg_catalog.pg_attribute a "		\
								"WHERE	c.relkind = 'r' AND "			\
								"		c.oid = a.attrelid AND "		\
								"		NOT a.attisdropped AND "		\
								"		a.atttypid = 'pg_catalog.tsvector'::pg_catalog.regtype AND " \
								"		c.relnamespace = n.oid AND "	\
								"       n.nspname !~ '^pg_' AND "		\
								"		n.nspname != 'information_schema') "

		ntups = PQntuples(res);
		i_nspname = PQfnumber(res, "nspname");
		i_relname = PQfnumber(res, "relname");
		i_attname = PQfnumber(res, "attname");
		for (rowno = 0; rowno < ntups; rowno++)
		{
			found = true;
			if (!check_mode)
			{
				if (script == NULL && (script = fopen(output_path, "w")) == NULL)
					pg_log(PG_FATAL, "could not create necessary file:  %s\n", output_path);
				if (!db_used)
				{
					fprintf(script, "\\connect %s\n\n",
							quote_identifier(active_db->db_name));
					db_used = true;
				}

				/* Rebuild all tsvector collumns with one ALTER TABLE command */
				if (strcmp(PQgetvalue(res, rowno, i_nspname), nspname) != 0 ||
					strcmp(PQgetvalue(res, rowno, i_relname), relname) != 0)
				{
					if (strlen(nspname) != 0 || strlen(relname) != 0)
						fprintf(script, ";\n\n");
					fprintf(script, "ALTER TABLE %s.%s\n",
						 quote_identifier(PQgetvalue(res, rowno, i_nspname)),
						quote_identifier(PQgetvalue(res, rowno, i_relname)));
//.........这里部分代码省略.........

int
main(int argc, char **argv)
{
	char	   *sequence_script_file_name = NULL;
	char	   *deletion_script_file_name = NULL;
	bool		live_check = false;

	parseCommandLine(argc, argv);

	output_check_banner(&live_check);

	setup(argv[0], live_check);

	check_cluster_versions();
	check_cluster_compatibility(live_check);

	check_old_cluster(live_check, &sequence_script_file_name);


	/* -- NEW -- */
	start_postmaster(&new_cluster);

	check_new_cluster();
	report_clusters_compatible();

	pg_log(PG_REPORT, "\nPerforming Upgrade\n");
	pg_log(PG_REPORT, "------------------\n");

	disable_old_cluster();
	prepare_new_cluster();

	stop_postmaster(false);

	/*
	 * Destructive Changes to New Cluster
	 */

	copy_clog_xlog_xid();

	/* New now using xids of the old system */

	/* -- NEW -- */
	start_postmaster(&new_cluster);

	prepare_new_databases();

	create_new_objects();

	stop_postmaster(false);

	transfer_all_new_dbs(&old_cluster.dbarr, &new_cluster.dbarr,
						 old_cluster.pgdata, new_cluster.pgdata);

	/*
	 * Assuming OIDs are only used in system tables, there is no need to
	 * restore the OID counter because we have not transferred any OIDs from
	 * the old system, but we do it anyway just in case.  We do it late here
	 * because there is no need to have the schema load use new oids.
	 */
	prep_status("Setting next oid for new cluster");
	exec_prog(true, SYSTEMQUOTE "\"%s/pg_resetxlog\" -o %u \"%s\" > "
			  DEVNULL SYSTEMQUOTE,
			  new_cluster.bindir, old_cluster.controldata.chkpnt_nxtoid, new_cluster.pgdata);
	check_ok();

	create_script_for_old_cluster_deletion(&deletion_script_file_name);

	issue_warnings(sequence_script_file_name);

	pg_log(PG_REPORT, "\nUpgrade complete\n");
	pg_log(PG_REPORT, "----------------\n");

	output_completion_banner(deletion_script_file_name);

	pg_free(deletion_script_file_name);
	pg_free(sequence_script_file_name);

	cleanup();

	return 0;
}

int
main(int argc, char **argv)
{
	char	   *sequence_script_file_name = NULL;
	char	   *analyze_script_file_name = NULL;
	char	   *deletion_script_file_name = NULL;
	bool		live_check = false;

	parseCommandLine(argc, argv);

	adjust_data_dir(&old_cluster);
	adjust_data_dir(&new_cluster);

	output_check_banner(&live_check);

	setup(argv[0], live_check);

	check_cluster_versions();

	get_sock_dir(&old_cluster, live_check);
	get_sock_dir(&new_cluster, false);

	check_cluster_compatibility(live_check);

	check_and_dump_old_cluster(live_check, &sequence_script_file_name);


	/* -- NEW -- */
	start_postmaster(&new_cluster);

	check_new_cluster();
	report_clusters_compatible();

	pg_log(PG_REPORT, "\nPerforming Upgrade\n");
	pg_log(PG_REPORT, "------------------\n");

	prepare_new_cluster();

	stop_postmaster(false);

	/*
	 * Destructive Changes to New Cluster
	 */

	copy_clog_xlog_xid();

	/* New now using xids of the old system */

	/* -- NEW -- */
	start_postmaster(&new_cluster);

	prepare_new_databases();

	create_new_objects();

	stop_postmaster(false);

	/*
	 * Most failures happen in create_new_objects(), which has completed at
	 * this point.	We do this here because it is just before linking, which
	 * will link the old and new cluster data files, preventing the old
	 * cluster from being safely started once the new cluster is started.
	 */
	if (user_opts.transfer_mode == TRANSFER_MODE_LINK)
		disable_old_cluster();

	transfer_all_new_dbs(&old_cluster.dbarr, &new_cluster.dbarr,
						 old_cluster.pgdata, new_cluster.pgdata);

	/*
	 * Assuming OIDs are only used in system tables, there is no need to
	 * restore the OID counter because we have not transferred any OIDs from
	 * the old system, but we do it anyway just in case.  We do it late here
	 * because there is no need to have the schema load use new oids.
	 */
	prep_status("Setting next OID for new cluster");
	exec_prog(UTILITY_LOG_FILE, NULL, true,
			  "\"%s/pg_resetxlog\" -o %u \"%s\"",
			  new_cluster.bindir, old_cluster.controldata.chkpnt_nxtoid,
			  new_cluster.pgdata);
	check_ok();

	prep_status("Sync data directory to disk");
	exec_prog(UTILITY_LOG_FILE, NULL, true,
			  "\"%s/initdb\" --sync-only \"%s\"", new_cluster.bindir,
			  new_cluster.pgdata);
	check_ok();

	create_script_for_cluster_analyze(&analyze_script_file_name);
	create_script_for_old_cluster_deletion(&deletion_script_file_name);

	issue_warnings(sequence_script_file_name);

	pg_log(PG_REPORT, "\nUpgrade Complete\n");
	pg_log(PG_REPORT, "----------------\n");

	output_completion_banner(analyze_script_file_name,
							 deletion_script_file_name);

	pg_free(analyze_script_file_name);
//.........这里部分代码省略.........

/*
 * check_loadable_libraries()
 *
 *	Check that the new cluster contains all required libraries.
 *	We do this by actually trying to LOAD each one, thereby testing
 *	compatibility as well as presence.
 */
void
check_loadable_libraries(void)
{
	PGconn	   *conn = connectToServer(&new_cluster, "template1");
	int			libnum;
	FILE	   *script = NULL;
	bool		found = false;
	char		output_path[MAXPGPATH];

	prep_status("Checking for presence of required libraries");

	snprintf(output_path, sizeof(output_path), "loadable_libraries.txt");

	for (libnum = 0; libnum < os_info.num_libraries; libnum++)
	{
		char	   *lib = os_info.libraries[libnum];
		int			llen = strlen(lib);
		char		cmd[7 + 2 * MAXPGPATH + 1];
		PGresult   *res;

		/*
		 * In Postgres 9.0, Python 3 support was added, and to do that, a
		 * plpython2u language was created with library name plpython2.so as a
		 * symbolic link to plpython.so.  In Postgres 9.1, only the
		 * plpython2.so library was created, and both plpythonu and plpython2u
		 * pointing to it.  For this reason, any reference to library name
		 * "plpython" in an old PG <= 9.1 cluster must look for "plpython2" in
		 * the new cluster.
		 *
		 * For this case, we could check pg_pltemplate, but that only works
		 * for languages, and does not help with function shared objects, so
		 * we just do a general fix.
		 */
		if (GET_MAJOR_VERSION(old_cluster.major_version) < 901 &&
			strcmp(lib, "$libdir/plpython") == 0)
		{
			lib = "$libdir/plpython2";
			llen = strlen(lib);
		}

		strcpy(cmd, "LOAD '");
		PQescapeStringConn(conn, cmd + strlen(cmd), lib, llen, NULL);
		strcat(cmd, "'");

		res = PQexec(conn, cmd);

		if (PQresultStatus(res) != PGRES_COMMAND_OK)
		{
			found = true;

			/* exit and report missing support library with special message */
			if (strcmp(lib, PG_UPGRADE_SUPPORT) == 0)
				pg_log(PG_FATAL,
					   "The pg_upgrade_support module must be created and installed in the new cluster.\n");

			if (script == NULL && (script = fopen_priv(output_path, "w")) == NULL)
				pg_log(PG_FATAL, "Could not open file \"%s\": %s\n",
					   output_path, getErrorText(errno));
			fprintf(script, "Could not load library \"%s\"\n%s\n",
					lib,
					PQerrorMessage(conn));
		}

		PQclear(res);
	}

	PQfinish(conn);

	if (found)
	{
		fclose(script);
		pg_log(PG_REPORT, "fatal\n");
		pg_log(PG_FATAL,
			   "Your installation references loadable libraries that are missing from the\n"
			   "new installation.  You can add these libraries to the new installation,\n"
			   "or remove the functions using them from the old installation.  A list of\n"
			   "problem libraries is in the file:\n"
			   "    %s\n\n", output_path);
	}
	else
		check_ok();
}

/*
 * get_loadable_libraries()
 *
 *	Fetch the names of all old libraries containing C-language functions.
 *	We will later check that they all exist in the new installation.
 */
void
get_loadable_libraries(void)
{
	PGresult  **ress;
	int			totaltups;
	int			dbnum;
	bool		found_public_plpython_handler = false;
	char	   *pg83_str;

	ress = (PGresult **) pg_malloc(old_cluster.dbarr.ndbs * sizeof(PGresult *));
	totaltups = 0;

	/*
	 * gpoptutils was removed during the 5.0 development cycle and the
	 * functionality is now in backend, skip when checking for loadable
	 * libraries in 4.3-> upgrades.
	 */
	if (GET_MAJOR_VERSION(old_cluster.major_version) == 802)
		pg83_str = "probin NOT IN ('$libdir/gpoptutils') AND ";
	else
		pg83_str = "";

	/* Fetch all library names, removing duplicates within each DB */
	for (dbnum = 0; dbnum < old_cluster.dbarr.ndbs; dbnum++)
	{
		DbInfo	   *active_db = &old_cluster.dbarr.dbs[dbnum];
		PGconn	   *conn = connectToServer(&old_cluster, active_db->db_name);

		/*
		 * Fetch all libraries referenced in this DB.  We can't exclude the
		 * "pg_catalog" schema because, while such functions are not
		 * explicitly dumped by pg_dump, they do reference implicit objects
		 * that pg_dump does dump, e.g. CREATE LANGUAGE plperl.
		 */
		ress[dbnum] = executeQueryOrDie(conn,
										"SELECT DISTINCT probin "
										"FROM	pg_catalog.pg_proc "
										"WHERE	prolang = 13 /* C */ AND "
										"probin IS NOT NULL AND "
										" %s "
										"oid >= %u;",
										pg83_str,
										FirstNormalObjectId);
		totaltups += PQntuples(ress[dbnum]);

		/*
		 * Systems that install plpython before 8.1 have
		 * plpython_call_handler() defined in the "public" schema, causing
		 * pg_dumpall to dump it.  However that function still references
		 * "plpython" (no "2"), so it throws an error on restore.  This code
		 * checks for the problem function, reports affected databases to the
		 * user and explains how to remove them. 8.1 git commit:
		 * e0dedd0559f005d60c69c9772163e69c204bac69
		 * http://archives.postgresql.org/pgsql-hackers/2012-03/msg01101.php
		 * http://archives.postgresql.org/pgsql-bugs/2012-05/msg00206.php
		 */
		if (GET_MAJOR_VERSION(old_cluster.major_version) < 901)
		{
			PGresult   *res;

			res = executeQueryOrDie(conn,
									"SELECT 1 "
						   "FROM	pg_catalog.pg_proc JOIN pg_namespace "
							 "		ON pronamespace = pg_namespace.oid "
							   "WHERE proname = 'plpython_call_handler' AND "
									"nspname = 'public' AND "
									"prolang = 13 /* C */ AND "
									"probin = '$libdir/plpython' AND "
									"pg_proc.oid >= %u;",
									FirstNormalObjectId);
			if (PQntuples(res) > 0)
			{
				if (!found_public_plpython_handler)
				{
					pg_log(PG_WARNING,
						   "\nThe old cluster has a \"plpython_call_handler\" function defined\n"
						   "in the \"public\" schema which is a duplicate of the one defined\n"
						   "in the \"pg_catalog\" schema.  You can confirm this by executing\n"
						   "in psql:\n"
						   "\n"
						   "    \\df *.plpython_call_handler\n"
						   "\n"
						   "The \"public\" schema version of this function was created by a\n"
						   "pre-8.1 install of plpython, and must be removed for pg_upgrade\n"
						   "to complete because it references a now-obsolete \"plpython\"\n"
						   "shared object file.  You can remove the \"public\" schema version\n"
					   "of this function by running the following command:\n"
						   "\n"
						 "    DROP FUNCTION public.plpython_call_handler()\n"
						   "\n"
						   "in each affected database:\n"
						   "\n");
				}
				pg_log(PG_WARNING, "    %s\n", active_db->db_name);
//.........这里部分代码省略.........

bool
start_postmaster(ClusterInfo *cluster, bool throw_error)
{
	char		cmd[MAXPGPATH * 4 + 1000];
	PGconn	   *conn;
	bool		pg_ctl_return = false;
	char		socket_string[MAXPGPATH + 200];

	static bool exit_hook_registered = false;

	if (!exit_hook_registered)
	{
		atexit(stop_postmaster_atexit);
		exit_hook_registered = true;
	}

	socket_string[0] = '\0';

#ifdef HAVE_UNIX_SOCKETS
	/* prevent TCP/IP connections, restrict socket access */
	strcat(socket_string,
		   " -c listen_addresses='' -c unix_socket_permissions=0700");

	/* Have a sockdir?	Tell the postmaster. */
	if (cluster->sockdir)
		snprintf(socket_string + strlen(socket_string),
				 sizeof(socket_string) - strlen(socket_string),
				 " -c %s='%s'",
				 (GET_MAJOR_VERSION(cluster->major_version) < 903) ?
				 "unix_socket_directory" : "unix_socket_directories",
				 cluster->sockdir);
#endif

	/*
	 * Since PG 9.1, we have used -b to disable autovacuum.  For earlier
	 * releases, setting autovacuum=off disables cleanup vacuum and analyze,
	 * but freeze vacuums can still happen, so we set
	 * autovacuum_freeze_max_age to its maximum.
	 * (autovacuum_multixact_freeze_max_age was introduced after 9.1, so there
	 * is no need to set that.)  We assume all datfrozenxid and relfrozenxid
	 * values are less than a gap of 2000000000 from the current xid counter,
	 * so autovacuum will not touch them.
	 *
	 * Turn off durability requirements to improve object creation speed, and
	 * we only modify the new cluster, so only use it there.  If there is a
	 * crash, the new cluster has to be recreated anyway.  fsync=off is a big
	 * win on ext4.
	 */
	snprintf(cmd, sizeof(cmd),
		  "\"%s/pg_ctl\" -w -l \"%s\" -D \"%s\" -o \"-p %d%s%s %s%s\" start",
		  cluster->bindir, SERVER_LOG_FILE, cluster->pgconfig, cluster->port,
			 (cluster->controldata.cat_ver >=
			  BINARY_UPGRADE_SERVER_FLAG_CAT_VER) ? " -b" :
			 " -c autovacuum=off -c autovacuum_freeze_max_age=2000000000",
			 (cluster == &new_cluster) ?
	  " -c synchronous_commit=off -c fsync=off -c full_page_writes=off" : "",
			 cluster->pgopts ? cluster->pgopts : "", socket_string);

	/*
	 * Don't throw an error right away, let connecting throw the error because
	 * it might supply a reason for the failure.
	 */
	pg_ctl_return = exec_prog(SERVER_START_LOG_FILE,
	/* pass both file names if they differ */
							  (strcmp(SERVER_LOG_FILE,
									  SERVER_START_LOG_FILE) != 0) ?
							  SERVER_LOG_FILE : NULL,
							  false,
							  "%s", cmd);

	/* Did it fail and we are just testing if the server could be started? */
	if (!pg_ctl_return && !throw_error)
		return false;

	/*
	 * We set this here to make sure atexit() shuts down the server, but only
	 * if we started the server successfully.  We do it before checking for
	 * connectivity in case the server started but there is a connectivity
	 * failure.  If pg_ctl did not return success, we will exit below.
	 *
	 * Pre-9.1 servers do not have PQping(), so we could be leaving the server
	 * running if authentication was misconfigured, so someday we might went
	 * to be more aggressive about doing server shutdowns even if pg_ctl
	 * fails, but now (2013-08-14) it seems prudent to be cautious.  We don't
	 * want to shutdown a server that might have been accidentally started
	 * during the upgrade.
	 */
	if (pg_ctl_return)
		os_info.running_cluster = cluster;

	/*
	 * pg_ctl -w might have failed because the server couldn't be started, or
	 * there might have been a connection problem in _checking_ if the server
	 * has started.  Therefore, even if pg_ctl failed, we continue and test
	 * for connectivity in case we get a connection reason for the failure.
	 */
	if ((conn = get_db_conn(cluster, "template1")) == NULL ||
		PQstatus(conn) != CONNECTION_OK)
	{
		pg_log(PG_REPORT, "\nconnection to database failed: %s\n",
//.........这里部分代码省略.........

/*
 * check_for_reg_data_type_usage()
 *	pg_upgrade only preserves these system values:
 *		pg_class.relfilenode
 *		pg_type.oid
 *		pg_enum.oid
 *
 *	Most of the reg* data types reference system catalog info that is
 *	not preserved, and hence these data types cannot be used in user
 *	tables upgraded by pg_upgrade.
 */
static void
check_for_reg_data_type_usage(ClusterInfo *cluster)
{
	int			dbnum;
	FILE	   *script = NULL;
	bool		found = false;
	char		output_path[MAX_PG_PATH];

	prep_status("Checking for reg* system oid user data types");

	snprintf(output_path, sizeof(output_path), "%s/tables_using_reg.txt",
			 os_info.cwd);

	for (dbnum = 0; dbnum < cluster->dbarr.ndbs; dbnum++)
	{
		PGresult   *res;
		bool		db_used = false;
		int			ntups;
		int			rowno;
		int			i_nspname,
					i_relname,
					i_attname;
		DbInfo	   *active_db = &cluster->dbarr.dbs[dbnum];
		PGconn	   *conn = connectToServer(cluster, active_db->db_name);

		res = executeQueryOrDie(conn,
								"SELECT n.nspname, c.relname, a.attname "
								"FROM	pg_catalog.pg_class c, "
								"		pg_catalog.pg_namespace n, "
								"		pg_catalog.pg_attribute a "
								"WHERE	c.oid = a.attrelid AND "
								"		NOT a.attisdropped AND "
								"		a.atttypid IN ( "
		  "			'pg_catalog.regproc'::pg_catalog.regtype, "
								"			'pg_catalog.regprocedure'::pg_catalog.regtype, "
		  "			'pg_catalog.regoper'::pg_catalog.regtype, "
								"			'pg_catalog.regoperator'::pg_catalog.regtype, "
		 "			'pg_catalog.regclass'::pg_catalog.regtype, "
		/* regtype.oid is preserved, so 'regtype' is OK */
		"			'pg_catalog.regconfig'::pg_catalog.regtype, "
								"			'pg_catalog.regdictionary'::pg_catalog.regtype) AND "
								"		c.relnamespace = n.oid AND "
							  "		n.nspname != 'pg_catalog' AND "
						 "		n.nspname != 'information_schema'");

		ntups = PQntuples(res);
		i_nspname = PQfnumber(res, "nspname");
		i_relname = PQfnumber(res, "relname");
		i_attname = PQfnumber(res, "attname");
		for (rowno = 0; rowno < ntups; rowno++)
		{
			found = true;
			if (script == NULL && (script = fopen(output_path, "w")) == NULL)
				pg_log(PG_FATAL, "Could not create necessary file:  %s\n", output_path);
			if (!db_used)
			{
				fprintf(script, "Database:  %s\n", active_db->db_name);
				db_used = true;
			}
			fprintf(script, "  %s.%s.%s\n",
					PQgetvalue(res, rowno, i_nspname),
					PQgetvalue(res, rowno, i_relname),
					PQgetvalue(res, rowno, i_attname));
		}

		PQclear(res);

		PQfinish(conn);
	}

	if (script)
		fclose(script);

	if (found)
	{
		pg_log(PG_REPORT, "fatal\n");
		pg_log(PG_FATAL,
			   "| Your installation contains one of the reg* data types in\n"
			   "| user tables.  These data types reference system oids that\n"
			   "| are not preserved by pg_upgrade, so this cluster cannot\n"
			   "| currently be upgraded.  You can remove the problem tables\n"
			   "| and restart the upgrade.  A list of the problem columns\n"
			   "| is in the file:\n"
			   "| \t%s\n\n", output_path);
	}
	else
		check_ok();
}

/*
 * get_control_data()
 *
 * gets pg_control information in "ctrl". Assumes that bindir and
 * datadir are valid absolute paths to postgresql bin and pgdata
 * directories respectively *and* pg_resetxlog is version compatible
 * with datadir. The main purpose of this function is to get pg_control
 * data in a version independent manner.
 *
 * The approach taken here is to invoke pg_resetxlog with -n option
 * and then pipe its output. With little string parsing we get the
 * pg_control data.  pg_resetxlog cannot be run while the server is running
 * so we use pg_controldata;  pg_controldata doesn't provide all the fields
 * we need to actually perform the migration, but it provides enough for
 * check mode.	We do not implement pg_resetxlog -n because it is hard to
 * return valid xid data for a running server.
 */
void
get_control_data(migratorContext *ctx, ClusterInfo *cluster, bool live_check)
{
	char		cmd[MAXPGPATH];
	char		bufin[MAX_STRING];
	FILE	   *output;
	char	   *p;
	bool		got_xid = false;
	bool		got_oid = false;
	bool		got_log_id = false;
	bool		got_log_seg = false;
	bool		got_tli = false;
	bool		got_align = false;
	bool		got_blocksz = false;
	bool		got_largesz = false;
	bool		got_walsz = false;
	bool		got_walseg = false;
	bool		got_ident = false;
	bool		got_index = false;
	bool		got_toast = false;
	bool		got_date_is_int = false;
	bool		got_float8_pass_by_value = false;
	char	   *lc_collate = NULL;
	char	   *lc_ctype = NULL;
	char	   *lc_monetary = NULL;
	char	   *lc_numeric = NULL;
	char	   *lc_time = NULL;
	char	   *lang = NULL;
	char	   *language = NULL;
	char	   *lc_all = NULL;
	char	   *lc_messages = NULL;

	/*
	 * Because we test the pg_resetxlog output as strings, it has to be in
	 * English.  Copied from pg_regress.c.
	 */
	if (getenv("LC_COLLATE"))
		lc_collate = pg_strdup(ctx, getenv("LC_COLLATE"));
	if (getenv("LC_CTYPE"))
		lc_ctype = pg_strdup(ctx, getenv("LC_CTYPE"));
	if (getenv("LC_MONETARY"))
		lc_monetary = pg_strdup(ctx, getenv("LC_MONETARY"));
	if (getenv("LC_NUMERIC"))
		lc_numeric = pg_strdup(ctx, getenv("LC_NUMERIC"));
	if (getenv("LC_TIME"))
		lc_time = pg_strdup(ctx, getenv("LC_TIME"));
	if (getenv("LANG"))
		lang = pg_strdup(ctx, getenv("LANG"));
	if (getenv("LANGUAGE"))
		language = pg_strdup(ctx, getenv("LANGUAGE"));
	if (getenv("LC_ALL"))
		lc_all = pg_strdup(ctx, getenv("LC_ALL"));
	if (getenv("LC_MESSAGES"))
		lc_messages = pg_strdup(ctx, getenv("LC_MESSAGES"));

	putenv2(ctx, "LC_COLLATE", NULL);
	putenv2(ctx, "LC_CTYPE", NULL);
	putenv2(ctx, "LC_MONETARY", NULL);
	putenv2(ctx, "LC_NUMERIC", NULL);
	putenv2(ctx, "LC_TIME", NULL);
	putenv2(ctx, "LANG",
#ifndef WIN32
			NULL);
#else
			/* On Windows the default locale cannot be English, so force it */
			"en");
#endif
	putenv2(ctx, "LANGUAGE", NULL);
	putenv2(ctx, "LC_ALL", NULL);
	putenv2(ctx, "LC_MESSAGES", "C");

	snprintf(cmd, sizeof(cmd),