/*
 * Actual code to make call to the database and print the output data.
 */
int
sql_exec(PGconn *conn, const char *todo, bool quiet)
{
	PGresult   *res;

	int			nfields;
	int			nrows;
	int			i,
				j,
				l;
	int		   *length;
	char	   *pad;

	/* make the call */
	res = PQexec(conn, todo);

	/* check and deal with errors */
	if (!res || PQresultStatus(res) > 2)
	{
		fprintf(stderr, "oid2name: query failed: %s\n", PQerrorMessage(conn));
		fprintf(stderr, "oid2name: query was: %s\n", todo);

		PQclear(res);
		PQfinish(conn);
		exit(-1);
	}

	/* get the number of fields */
	nrows = PQntuples(res);
	nfields = PQnfields(res);

	/* for each field, get the needed width */
	length = (int *) pg_malloc(sizeof(int) * nfields);
	for (j = 0; j < nfields; j++)
		length[j] = strlen(PQfname(res, j));

	for (i = 0; i < nrows; i++)
	{
		for (j = 0; j < nfields; j++)
		{
			l = strlen(PQgetvalue(res, i, j));
			if (l > length[j])
				length[j] = strlen(PQgetvalue(res, i, j));
		}
	}

	/* print a header */
	if (!quiet)
	{
		for (j = 0, l = 0; j < nfields; j++)
		{
			fprintf(stdout, "%*s", length[j] + 2, PQfname(res, j));
			l += length[j] + 2;
		}
		fprintf(stdout, "\n");
		pad = (char *) pg_malloc(l + 1);
		MemSet(pad, '-', l);
		pad[l] = '\0';
		fprintf(stdout, "%s\n", pad);
		free(pad);
	}

	/* for each row, dump the information */
	for (i = 0; i < nrows; i++)
	{
		for (j = 0; j < nfields; j++)
			fprintf(stdout, "%*s", length[j] + 2, PQgetvalue(res, i, j));
		fprintf(stdout, "\n");
	}

	/* cleanup */
	PQclear(res);
	free(length);

	return 0;
}

static int
copy_file(const char *srcfile, const char *dstfile, bool force)
{
#define COPY_BUF_SIZE (50 * BLCKSZ)

	int			src_fd;
	int			dest_fd;
	char	   *buffer;
	int			ret = 0;
	int			save_errno = 0;

	if ((srcfile == NULL) || (dstfile == NULL))
	{
		errno = EINVAL;
		return -1;
	}

	if ((src_fd = open(srcfile, O_RDONLY, 0)) < 0)
		return -1;

	if ((dest_fd = open(dstfile, O_RDWR | O_CREAT | (force ? 0 : O_EXCL), S_IRUSR | S_IWUSR)) < 0)
	{
		save_errno = errno;

		if (src_fd != 0)
			close(src_fd);

		errno = save_errno;
		return -1;
	}

	buffer = (char *) pg_malloc(COPY_BUF_SIZE);

	/* perform data copying i.e read src source, write to destination */
	while (true)
	{
		ssize_t		nbytes = read(src_fd, buffer, COPY_BUF_SIZE);

		if (nbytes < 0)
		{
			save_errno = errno;
			ret = -1;
			break;
		}

		if (nbytes == 0)
			break;

		errno = 0;

		if (write(dest_fd, buffer, nbytes) != nbytes)
		{
			/* if write didn't set errno, assume problem is no disk space */
			if (errno == 0)
				errno = ENOSPC;
			save_errno = errno;
			ret = -1;
			break;
		}
	}

	pg_free(buffer);

	if (src_fd != 0)
		close(src_fd);

	if (dest_fd != 0)
		close(dest_fd);

	if (save_errno != 0)
		errno = save_errno;

	return ret;
}

/*
 * 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.........

/*
 *	parallel_transfer_all_new_dbs
 *
 *	This has the same API as transfer_all_new_dbs, except it does parallel execution
 *	by transferring multiple tablespaces in parallel
 */
void
parallel_transfer_all_new_dbs(DbInfoArr *old_db_arr, DbInfoArr *new_db_arr,
							  char *old_pgdata, char *new_pgdata,
							  char *old_tablespace)
{
#ifndef WIN32
	pid_t		child;
#else
	HANDLE		child;
	transfer_thread_arg *new_arg;
#endif

	if (user_opts.jobs <= 1)
		/* throw_error must be true to allow jobs */
		transfer_all_new_dbs(old_db_arr, new_db_arr, old_pgdata, new_pgdata, NULL);
	else
	{
		/* parallel */
#ifdef WIN32
		if (thread_handles == NULL)
			thread_handles = pg_malloc(user_opts.jobs * sizeof(HANDLE));

		if (transfer_thread_args == NULL)
		{
			int			i;

			transfer_thread_args = pg_malloc(user_opts.jobs * sizeof(transfer_thread_arg *));

			/*
			 * For safety and performance, we keep the args allocated during
			 * the entire life of the process, and we don't free the args in a
			 * thread different from the one that allocated it.
			 */
			for (i = 0; i < user_opts.jobs; i++)
				transfer_thread_args[i] = pg_malloc0(sizeof(transfer_thread_arg));
		}

		cur_thread_args = (void **) transfer_thread_args;
#endif
		/* harvest any dead children */
		while (reap_child(false) == true)
			;

		/* must we wait for a dead child? */
		if (parallel_jobs >= user_opts.jobs)
			reap_child(true);

		/* set this before we start the job */
		parallel_jobs++;

		/* Ensure stdio state is quiesced before forking */
		fflush(NULL);

#ifndef WIN32
		child = fork();
		if (child == 0)
		{
			transfer_all_new_dbs(old_db_arr, new_db_arr, old_pgdata, new_pgdata,
								 old_tablespace);
			/* if we take another exit path, it will be non-zero */
			/* use _exit to skip atexit() functions */
			_exit(0);
		}
		else if (child < 0)
			/* fork failed */
			pg_fatal("could not create worker process: %s\n", strerror(errno));
#else
		/* empty array element are always at the end */
		new_arg = transfer_thread_args[parallel_jobs - 1];

		/* Can only pass one pointer into the function, so use a struct */
		new_arg->old_db_arr = old_db_arr;
		new_arg->new_db_arr = new_db_arr;
		if (new_arg->old_pgdata)
			pg_free(new_arg->old_pgdata);
		new_arg->old_pgdata = pg_strdup(old_pgdata);
		if (new_arg->new_pgdata)
			pg_free(new_arg->new_pgdata);
		new_arg->new_pgdata = pg_strdup(new_pgdata);
		if (new_arg->old_tablespace)
			pg_free(new_arg->old_tablespace);
		new_arg->old_tablespace = old_tablespace ? pg_strdup(old_tablespace) : NULL;

		child = (HANDLE) _beginthreadex(NULL, 0, (void *) win32_transfer_all_new_dbs,
										new_arg, 0, NULL);
		if (child == 0)
			pg_fatal("could not create worker thread: %s\n", strerror(errno));

		thread_handles[parallel_jobs - 1] = child;
#endif
	}

	return;
}

/*
 * Try to read the existing pg_control file.
 *
 * This routine is also responsible for updating old pg_control versions
 * to the current format.  (Currently we don't do anything of the sort.)
 */
static bool
ReadControlFile(void)
{
	int			fd;
	int			len;
	char	   *buffer;
	pg_crc32	crc;

	if ((fd = open(XLOG_CONTROL_FILE, O_RDONLY | PG_BINARY, 0)) < 0)
	{
		/*
		 * If pg_control is not there at all, or we can't read it, the odds
		 * are we've been handed a bad DataDir path, so give up. User can do
		 * "touch pg_control" to force us to proceed.
		 */
		fprintf(stderr, _("%s: could not open file \"%s\" for reading: %s\n"),
				progname, XLOG_CONTROL_FILE, strerror(errno));
		if (errno == ENOENT)
			fprintf(stderr, _("If you are sure the data directory path is correct, execute\n"
							  "  touch %s\n"
							  "and try again.\n"),
					XLOG_CONTROL_FILE);
		exit(1);
	}

	/* Use malloc to ensure we have a maxaligned buffer */
	buffer = (char *) pg_malloc(PG_CONTROL_SIZE);

	len = read(fd, buffer, PG_CONTROL_SIZE);
	if (len < 0)
	{
		fprintf(stderr, _("%s: could not read file \"%s\": %s\n"),
				progname, XLOG_CONTROL_FILE, strerror(errno));
		exit(1);
	}
	close(fd);

	if (len >= sizeof(ControlFileData) &&
	  ((ControlFileData *) buffer)->pg_control_version == PG_CONTROL_VERSION)
	{
		/* Check the CRC. */
		INIT_CRC32(crc);
		COMP_CRC32(crc,
				   buffer,
				   offsetof(ControlFileData, crc));
		FIN_CRC32(crc);

		if (EQ_CRC32(crc, ((ControlFileData *) buffer)->crc))
		{
			/* Valid data... */
			memcpy(&ControlFile, buffer, sizeof(ControlFile));
			return true;
		}

		fprintf(stderr, _("%s: pg_control exists but has invalid CRC; proceed with caution\n"),
				progname);
		/* We will use the data anyway, but treat it as guessed. */
		memcpy(&ControlFile, buffer, sizeof(ControlFile));
		guessed = true;
		return true;
	}

	/* Looks like it's a mess. */
	fprintf(stderr, _("%s: pg_control exists but is broken or unknown version; ignoring it\n"),
			progname);
	return false;
}

/*
 * Replacement for strtok() (a.k.a. poor man's flex)
 *
 * Splits a string into tokens, returning one token per call, then NULL
 * when no more tokens exist in the given string.
 *
 * The calling convention is similar to that of strtok, but with more
 * frammishes.
 *
 * s -			string to parse, if NULL continue parsing the last string
 * whitespace - set of whitespace characters that separate tokens
 * delim -		set of non-whitespace separator characters (or NULL)
 * quote -		set of characters that can quote a token (NULL if none)
 * escape -		character that can quote quotes (0 if none)
 * e_strings -	if TRUE, treat E'...' syntax as a valid token
 * del_quotes - if TRUE, strip quotes from the returned token, else return
 *				it exactly as found in the string
 * encoding -	the active character-set encoding
 *
 * Characters in 'delim', if any, will be returned as single-character
 * tokens unless part of a quoted token.
 *
 * Double occurrences of the quoting character are always taken to represent
 * a single quote character in the data.  If escape isn't 0, then escape
 * followed by anything (except \0) is a data character too.
 *
 * The combination of e_strings and del_quotes both TRUE is not currently
 * handled.  This could be fixed but it's not needed anywhere at the moment.
 *
 * Note that the string s is _not_ overwritten in this implementation.
 *
 * NB: it's okay to vary delim, quote, and escape from one call to the
 * next on a single source string, but changing whitespace is a bad idea
 * since you might lose data.
 */
char *
strtokx(const char *s,
        const char *whitespace,
        const char *delim,
        const char *quote,
        char escape,
        bool e_strings,
        bool del_quotes,
        int encoding)
{
    static char *storage = NULL;/* store the local copy of the users string
                                 * here */
    static char *string = NULL; /* pointer into storage where to continue on
                                 * next call */
    
    /* variously abused variables: */
    unsigned int offset;
    char	   *start;
    char	   *p;
    
    if (s)
    {
        free(storage);
        
        /*
         * We may need extra space to insert delimiter nulls for adjacent
         * tokens.  2X the space is a gross overestimate, but it's unlikely
         * that this code will be used on huge strings anyway.
         */
        storage = pg_malloc(2 * strlen(s) + 1);
        strcpy(storage, s);
        string = storage;
    }
    
    if (!storage)
        return NULL;
    
    /* skip leading whitespace */
    offset = strspn(string, whitespace);
    start = &string[offset];
    
    /* end of string reached? */
    if (*start == '\0')
    {
        /* technically we don't need to free here, but we're nice */
        free(storage);
        storage = NULL;
        string = NULL;
        return NULL;
    }
    
    /* test if delimiter character */
    if (delim && strchr(delim, *start))
    {
        /*
         * If not at end of string, we need to insert a null to terminate the
         * returned token.  We can just overwrite the next character if it
         * happens to be in the whitespace set ... otherwise move over the
         * rest of the string to make room.  (This is why we allocated extra
         * space above).
         */
        p = start + 1;
        if (*p != '\0')
        {
            if (!strchr(whitespace, *p))
//.........这里部分代码省略.........

/*
 *
 * main
 *
 */
int
main(int argc, char *argv[])
{
	struct adhoc_opts options;
	int			successResult;
	char	   *password = NULL;
	char	   *password_prompt = NULL;
	bool		new_pass;

	set_pglocale_pgservice(argv[0], PG_TEXTDOMAIN("psql"));

	if (argc > 1)
	{
		if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0)
		{
			usage();
			exit(EXIT_SUCCESS);
		}
		if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0)
		{
			showVersion();
			exit(EXIT_SUCCESS);
		}
	}

#ifdef WIN32
	setvbuf(stderr, NULL, _IONBF, 0);
#endif

	setup_cancel_handler();

	pset.progname = get_progname(argv[0]);

	pset.db = NULL;
	setDecimalLocale();
	pset.encoding = PQenv2encoding();
	pset.queryFout = stdout;
	pset.queryFoutPipe = false;
	pset.cur_cmd_source = stdin;
	pset.cur_cmd_interactive = false;

	/* We rely on unmentioned fields of pset.popt to start out 0/false/NULL */
	pset.popt.topt.format = PRINT_ALIGNED;
	pset.popt.topt.border = 1;
	pset.popt.topt.pager = 1;
	pset.popt.topt.start_table = true;
	pset.popt.topt.stop_table = true;
	pset.popt.default_footer = true;
	/* We must get COLUMNS here before readline() sets it */
	pset.popt.topt.env_columns = getenv("COLUMNS") ? atoi(getenv("COLUMNS")) : 0;

	pset.notty = (!isatty(fileno(stdin)) || !isatty(fileno(stdout)));

	pset.getPassword = TRI_DEFAULT;

	EstablishVariableSpace();

	SetVariable(pset.vars, "VERSION", PG_VERSION_STR);

	/* Default values for variables */
	SetVariableBool(pset.vars, "AUTOCOMMIT");
	SetVariable(pset.vars, "VERBOSITY", "default");
	SetVariable(pset.vars, "PROMPT1", DEFAULT_PROMPT1);
	SetVariable(pset.vars, "PROMPT2", DEFAULT_PROMPT2);
	SetVariable(pset.vars, "PROMPT3", DEFAULT_PROMPT3);

	parse_psql_options(argc, argv, &options);

	if (!pset.popt.topt.fieldSep)
		pset.popt.topt.fieldSep = pg_strdup(DEFAULT_FIELD_SEP);
	if (!pset.popt.topt.recordSep)
		pset.popt.topt.recordSep = pg_strdup(DEFAULT_RECORD_SEP);

	if (options.username == NULL)
		password_prompt = pg_strdup(_("Password: "));
	else
	{
		password_prompt = malloc(strlen(_("Password for user %s: ")) - 2 +
								 strlen(options.username) + 1);
		sprintf(password_prompt, _("Password for user %s: "),
				options.username);
	}

	if (pset.getPassword == TRI_YES)
		password = simple_prompt(password_prompt, 100, false);

	/* loop until we have a password if requested by backend */
	do
	{
#define PARAMS_ARRAY_SIZE	7
		const char **keywords = pg_malloc(PARAMS_ARRAY_SIZE * sizeof(*keywords));
		const char **values = pg_malloc(PARAMS_ARRAY_SIZE * sizeof(*values));

		keywords[0] = "host";
		values[0] = options.host;
//.........这里部分代码省略.........

//.........这里部分代码省略.........
	{
		appendPQExpBufferStr(&buf,
							 fmtQualifiedId(PQgetvalue(res, i, 1),
											PQgetvalue(res, i, 0)));

		if (tables_listed && !PQgetisnull(res, i, 2))
			appendPQExpBufferStr(&buf, PQgetvalue(res, i, 2));

		simple_string_list_append(&dbtables, buf.data);
		resetPQExpBuffer(&buf);
	}
	termPQExpBuffer(&buf);
	PQclear(res);

	/*
	 * If there are more connections than vacuumable relations, we don't need
	 * to use them all.
	 */
	if (parallel)
	{
		if (concurrentCons > ntups)
			concurrentCons = ntups;
		if (concurrentCons <= 1)
			parallel = false;
	}

	/*
	 * Setup the database connections. We reuse the connection we already have
	 * for the first slot.  If not in parallel mode, the first slot in the
	 * array contains the connection.
	 */
	if (concurrentCons <= 0)
		concurrentCons = 1;
	slots = (ParallelSlot *) pg_malloc(sizeof(ParallelSlot) * concurrentCons);
	init_slot(slots, conn);
	if (parallel)
	{
		for (i = 1; i < concurrentCons; i++)
		{
			conn = connectDatabase(dbname, host, port, username, prompt_password,
								   progname, echo, false, true);
			init_slot(slots + i, conn);
		}
	}

	/*
	 * Prepare all the connections to run the appropriate analyze stage, if
	 * caller requested that mode.
	 */
	if (stage != ANALYZE_NO_STAGE)
	{
		int			j;

		/* We already emitted the message above */

		for (j = 0; j < concurrentCons; j++)
			executeCommand((slots + j)->connection,
						   stage_commands[stage], progname, echo);
	}

	initPQExpBuffer(&sql);

	cell = dbtables.head;
	do
	{
		const char *tabname = cell->val;

/*
 * Try to set the wal segment size from the WAL file specified by WALFilePath.
 *
 * Return true if size could be determined, false otherwise.
 */
static bool
SetWALSegSize(void)
{
	bool		ret_val = false;
	int			fd;

	/* malloc this buffer to ensure sufficient alignment: */
	char	   *buf = (char *) pg_malloc(XLOG_BLCKSZ);

	Assert(WalSegSz == -1);

	if ((fd = open(WALFilePath, O_RDWR, 0)) < 0)
	{
		fprintf(stderr, "%s: could not open WAL file \"%s\": %s\n",
				progname, WALFilePath, strerror(errno));
		pg_free(buf);
		return false;
	}

	errno = 0;
	if (read(fd, buf, XLOG_BLCKSZ) == XLOG_BLCKSZ)
	{
		XLogLongPageHeader longhdr = (XLogLongPageHeader) buf;

		WalSegSz = longhdr->xlp_seg_size;

		if (IsValidWalSegSize(WalSegSz))
		{
			/* successfully retrieved WAL segment size */
			ret_val = true;
		}
		else
			fprintf(stderr,
					"%s: WAL segment size must be a power of two between 1MB and 1GB, but the WAL file header specifies %d bytes\n",
					progname, WalSegSz);
	}
	else
	{
		/*
		 * Don't complain loudly, this is to be expected for segments being
		 * created.
		 */
		if (errno != 0)
		{
			if (debug)
				fprintf(stderr, "could not read file \"%s\": %s\n",
						WALFilePath, strerror(errno));
		}
		else
		{
			if (debug)
				fprintf(stderr, "not enough data in file \"%s\"\n",
						WALFilePath);
		}
	}

	fflush(stderr);

	close(fd);
	pg_free(buf);
	return ret_val;
}

/*
 * gen_db_file_maps()
 *
 * generates database mappings for "old_db" and "new_db". Returns a malloc'ed
 * array of mappings. nmaps is a return parameter which refers to the number
 * mappings.
 *
 * NOTE: Its the Caller's responsibility to free the returned array.
 */
FileNameMap *
gen_db_file_maps(migratorContext *ctx, DbInfo *old_db, DbInfo *new_db,
				 int *nmaps, const char *old_pgdata, const char *new_pgdata)
{
	FileNameMap *maps;
	int			relnum;
	int			num_maps = 0;

	maps = (FileNameMap *) pg_malloc(ctx, sizeof(FileNameMap) *
									 new_db->rel_arr.nrels);

	for (relnum = 0; relnum < new_db->rel_arr.nrels; relnum++)
	{
		RelInfo    *newrel = &new_db->rel_arr.rels[relnum];
		RelInfo    *oldrel;

		/* toast tables are handled by their parent */
		if (strcmp(newrel->nspname, "pg_toast") == 0)
			continue;

		oldrel = relarr_lookup_rel(ctx, &(old_db->rel_arr), newrel->nspname,
								   newrel->relname, CLUSTER_OLD);

		map_rel(ctx, oldrel, newrel, old_db, new_db, old_pgdata, new_pgdata,
				maps + num_maps);
		num_maps++;

		/*
		 * so much for the mapping of this relation. Now we need a mapping for
		 * its corresponding toast relation if any.
		 */
		if (oldrel->toastrelid > 0)
		{
			RelInfo    *new_toast;
			RelInfo    *old_toast;
			char		new_name[MAXPGPATH];
			char		old_name[MAXPGPATH];

			/* construct the new and old relnames for the toast relation */
			snprintf(old_name, sizeof(old_name), "pg_toast_%u",
					 oldrel->reloid);
			snprintf(new_name, sizeof(new_name), "pg_toast_%u",
					 newrel->reloid);

			/* look them up in their respective arrays */
			old_toast = relarr_lookup_reloid(ctx, &old_db->rel_arr,
											 oldrel->toastrelid, CLUSTER_OLD);
			new_toast = relarr_lookup_rel(ctx, &new_db->rel_arr,
										  "pg_toast", new_name, CLUSTER_NEW);

			/* finally create a mapping for them */
			map_rel(ctx, old_toast, new_toast, old_db, new_db, old_pgdata, new_pgdata,
					maps + num_maps);
			num_maps++;

			/*
			 * also need to provide a mapping for the index of this toast
			 * relation. The procedure is similar to what we did above for
			 * toast relation itself, the only difference being that the
			 * relnames need to be appended with _index.
			 */

			/*
			 * construct the new and old relnames for the toast index
			 * relations
			 */
			snprintf(old_name, sizeof(old_name), "%s_index", old_toast->relname);
			snprintf(new_name, sizeof(new_name), "pg_toast_%u_index",
					 newrel->reloid);

			/* look them up in their respective arrays */
			old_toast = relarr_lookup_rel(ctx, &old_db->rel_arr,
										  "pg_toast", old_name, CLUSTER_OLD);
			new_toast = relarr_lookup_rel(ctx, &new_db->rel_arr,
										  "pg_toast", new_name, CLUSTER_NEW);

			/* finally create a mapping for them */
			map_rel(ctx, old_toast, new_toast, old_db, new_db, old_pgdata,
					new_pgdata, maps + num_maps);
			num_maps++;
		}
	}

	*nmaps = num_maps;
	return maps;
}

static void
ReadDataFromArchiveZlib(ArchiveHandle *AH, ReadFunc readF)
{
	z_streamp	zp;
	char	   *out;
	int			res = Z_OK;
	size_t		cnt;
	char	   *buf;
	size_t		buflen;

	zp = (z_streamp) pg_malloc(sizeof(z_stream));
	zp->zalloc = Z_NULL;
	zp->zfree = Z_NULL;
	zp->opaque = Z_NULL;

	buf = pg_malloc(ZLIB_IN_SIZE);
	buflen = ZLIB_IN_SIZE;

	out = pg_malloc(ZLIB_OUT_SIZE + 1);

	if (inflateInit(zp) != Z_OK)
		exit_horribly(modulename,
					  "could not initialize compression library: %s\n",
					  zp->msg);

	/* no minimal chunk size for zlib */
	while ((cnt = readF(AH, &buf, &buflen)))
	{
		zp->next_in = (void *) buf;
		zp->avail_in = cnt;

		while (zp->avail_in > 0)
		{
			zp->next_out = (void *) out;
			zp->avail_out = ZLIB_OUT_SIZE;

			res = inflate(zp, 0);
			if (res != Z_OK && res != Z_STREAM_END)
				exit_horribly(modulename,
							  "could not uncompress data: %s\n", zp->msg);

			out[ZLIB_OUT_SIZE - zp->avail_out] = '\0';
			ahwrite(out, 1, ZLIB_OUT_SIZE - zp->avail_out, AH);
		}
	}

	zp->next_in = NULL;
	zp->avail_in = 0;
	while (res != Z_STREAM_END)
	{
		zp->next_out = (void *) out;
		zp->avail_out = ZLIB_OUT_SIZE;
		res = inflate(zp, 0);
		if (res != Z_OK && res != Z_STREAM_END)
			exit_horribly(modulename,
						  "could not uncompress data: %s\n", zp->msg);

		out[ZLIB_OUT_SIZE - zp->avail_out] = '\0';
		ahwrite(out, 1, ZLIB_OUT_SIZE - zp->avail_out, AH);
	}

	if (inflateEnd(zp) != Z_OK)
		exit_horribly(modulename,
					  "could not close compression library: %s\n", zp->msg);

	free(buf);
	free(out);
	free(zp);
}

/*----
 * 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.........

int
main(int argc, char **argv)
{
	struct options *my_opts;
	PGconn	   *pgconn;

	my_opts = (struct options *) pg_malloc(sizeof(struct options));

	my_opts->oids = (eary *) pg_malloc(sizeof(eary));
	my_opts->tables = (eary *) pg_malloc(sizeof(eary));
	my_opts->filenodes = (eary *) pg_malloc(sizeof(eary));

	my_opts->oids->num = my_opts->oids->alloc = 0;
	my_opts->tables->num = my_opts->tables->alloc = 0;
	my_opts->filenodes->num = my_opts->filenodes->alloc = 0;

	/* parse the opts */
	get_opts(argc, argv, my_opts);

	if (my_opts->dbname == NULL)
	{
		my_opts->dbname = "postgres";
		my_opts->nodb = true;
	}
	pgconn = sql_conn(my_opts);

	/* display only tablespaces */
	if (my_opts->tablespaces)
	{
		if (!my_opts->quiet)
			printf("All tablespaces:\n");
		sql_exec_dumpalltbspc(pgconn, my_opts);

		PQfinish(pgconn);
		exit(0);
	}

	/* display the given elements in the database */
	if (my_opts->oids->num > 0 ||
		my_opts->tables->num > 0 ||
		my_opts->filenodes->num > 0)
	{
		if (!my_opts->quiet)
			printf("From database \"%s\":\n", my_opts->dbname);
		sql_exec_searchtables(pgconn, my_opts);

		PQfinish(pgconn);
		exit(0);
	}

	/* no elements given; dump the given database */
	if (my_opts->dbname && !my_opts->nodb)
	{
		if (!my_opts->quiet)
			printf("From database \"%s\":\n", my_opts->dbname);
		sql_exec_dumpalltables(pgconn, my_opts);

		PQfinish(pgconn);
		exit(0);
	}

	/* no database either; dump all databases */
	if (!my_opts->quiet)
		printf("All databases:\n");
	sql_exec_dumpalldbs(pgconn, my_opts);

	PQfinish(pgconn);
	return 0;
}

/*
 * Show oid, filenode, name, schema and tablespace for each of the
 * given objects in the current database.
 */
void
sql_exec_searchtables(PGconn *conn, struct options * opts)
{
	char	   *todo;
	char	   *qualifiers,
			   *ptr;
	char	   *comma_oids,
			   *comma_filenodes,
			   *comma_tables;
	bool		written = false;
	char	   *addfields = ",c.oid AS \"Oid\", nspname AS \"Schema\", spcname as \"Tablespace\" ";

	/* get tables qualifiers, whether names, filenodes, or OIDs */
	comma_oids = get_comma_elts(opts->oids);
	comma_tables = get_comma_elts(opts->tables);
	comma_filenodes = get_comma_elts(opts->filenodes);

	/* 80 extra chars for SQL expression */
	qualifiers = (char *) pg_malloc(strlen(comma_oids) + strlen(comma_tables) +
									strlen(comma_filenodes) + 80);
	ptr = qualifiers;

	if (opts->oids->num > 0)
	{
		ptr += sprintf(ptr, "c.oid IN (%s)", comma_oids);
		written = true;
	}
	if (opts->filenodes->num > 0)
	{
		if (written)
			ptr += sprintf(ptr, " OR ");
		ptr += sprintf(ptr, "pg_catalog.pg_relation_filenode(c.oid) IN (%s)", comma_filenodes);
		written = true;
	}
	if (opts->tables->num > 0)
	{
		if (written)
			ptr += sprintf(ptr, " OR ");
		sprintf(ptr, "c.relname ~~ ANY (ARRAY[%s])", comma_tables);
	}
	free(comma_oids);
	free(comma_tables);
	free(comma_filenodes);

	/* now build the query */
	todo = psprintf(
					"SELECT pg_catalog.pg_relation_filenode(c.oid) as \"Filenode\", relname as \"Table Name\" %s\n"
					"FROM pg_catalog.pg_class c \n"
		"	LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace \n"
					"	LEFT JOIN pg_catalog.pg_database d ON d.datname = pg_catalog.current_database(),\n"
					"	pg_catalog.pg_tablespace t \n"
					"WHERE relkind IN ('r', 'm', 'i', 'S', 't') AND \n"
					"		t.oid = CASE\n"
			"			WHEN reltablespace <> 0 THEN reltablespace\n"
					"			ELSE dattablespace\n"
					"		END AND \n"
					"  (%s) \n"
					"ORDER BY relname\n",
					opts->extended ? addfields : "",
					qualifiers);

	free(qualifiers);

	sql_exec(conn, todo, opts->quiet);
}

/*
 * Callback for processing target file list.
 *
 * All source files must be already processed before calling this. This only
 * marks target data directory's files that didn't exist in the source for
 * deletion.
 */
void
process_target_file(const char *path, file_type_t type, size_t oldsize,
					const char *link_target)
{
	bool		exists;
	char		localpath[MAXPGPATH];
	struct stat statbuf;
	file_entry_t key;
	file_entry_t *key_ptr;
	filemap_t  *map = filemap;
	file_entry_t *entry;

	snprintf(localpath, sizeof(localpath), "%s/%s", datadir_target, path);
	if (lstat(localpath, &statbuf) < 0)
	{
		if (errno != ENOENT)
			pg_fatal("could not stat file \"%s\": %s\n",
					 localpath, strerror(errno));

		exists = false;
	}

	if (map->array == NULL)
	{
		/* on first call, initialize lookup array */
		if (map->nlist == 0)
		{
			/* should not happen */
			pg_fatal("source file list is empty\n");
		}

		filemap_list_to_array(map);

		Assert(map->array != NULL);

		qsort(map->array, map->narray, sizeof(file_entry_t *), path_cmp);
	}

	/*
	 * Completely ignore some special files
	 */
	if (strcmp(path, "postmaster.pid") == 0 ||
		strcmp(path, "postmaster.opts") == 0)
		return;

	/*
	 * Like in process_source_file, pretend that xlog is always a  directory.
	 */
	if (strcmp(path, "pg_wal") == 0 && type == FILE_TYPE_SYMLINK)
		type = FILE_TYPE_DIRECTORY;

	key.path = (char *) path;
	key_ptr = &key;
	exists = (bsearch(&key_ptr, map->array, map->narray, sizeof(file_entry_t *),
					  path_cmp) != NULL);

	/* Remove any file or folder that doesn't exist in the source system. */
	if (!exists)
	{
		entry = pg_malloc(sizeof(file_entry_t));
		entry->path = pg_strdup(path);
		entry->type = type;
		entry->action = FILE_ACTION_REMOVE;
		entry->oldsize = oldsize;
		entry->newsize = 0;
		entry->link_target = link_target ? pg_strdup(link_target) : NULL;
		entry->next = NULL;
		entry->pagemap.bitmap = NULL;
		entry->pagemap.bitmapsize = 0;
		entry->isrelfile = isRelDataFile(path);

		if (map->last == NULL)
			map->first = entry;
		else
			map->last->next = entry;
		map->last = entry;
		map->nlist++;
	}
	else
	{
		/*
		 * We already handled all files that exist in the source system in
		 * process_source_file().
		 */
	}
}

/*
 * create_script_for_cluster_analyze()
 *
 *	This incrementally generates better optimizer statistics
 */
void
create_script_for_cluster_analyze(char **analyze_script_file_name)
{
	FILE	   *script = NULL;

	*analyze_script_file_name = pg_malloc(MAXPGPATH);

	prep_status("Creating script to analyze new cluster");

	snprintf(*analyze_script_file_name, MAXPGPATH, "analyze_new_cluster.%s",
			 SCRIPT_EXT);

	if ((script = fopen_priv(*analyze_script_file_name, "w")) == NULL)
		pg_log(PG_FATAL, "Could not open file \"%s\": %s\n",
			   *analyze_script_file_name, getErrorText(errno));

#ifndef WIN32
	/* add shebang header */
	fprintf(script, "#!/bin/sh\n\n");
#endif

	fprintf(script, "echo %sThis script will generate minimal optimizer statistics rapidly%s\n",
			ECHO_QUOTE, ECHO_QUOTE);
	fprintf(script, "echo %sso your system is usable, and then gather statistics twice more%s\n",
			ECHO_QUOTE, ECHO_QUOTE);
	fprintf(script, "echo %swith increasing accuracy.  When it is done, your system will%s\n",
			ECHO_QUOTE, ECHO_QUOTE);
	fprintf(script, "echo %shave the default level of optimizer statistics.%s\n",
			ECHO_QUOTE, ECHO_QUOTE);
	fprintf(script, "echo\n\n");

	fprintf(script, "echo %sIf you have used ALTER TABLE to modify the statistics target for%s\n",
			ECHO_QUOTE, ECHO_QUOTE);
	fprintf(script, "echo %sany tables, you might want to remove them and restore them after%s\n",
			ECHO_QUOTE, ECHO_QUOTE);
	fprintf(script, "echo %srunning this script because they will delay fast statistics generation.%s\n",
			ECHO_QUOTE, ECHO_QUOTE);
	fprintf(script, "echo\n\n");

	fprintf(script, "echo %sIf you would like default statistics as quickly as possible, cancel%s\n",
			ECHO_QUOTE, ECHO_QUOTE);
	fprintf(script, "echo %sthis script and run:%s\n",
			ECHO_QUOTE, ECHO_QUOTE);
	fprintf(script, "echo %s    vacuumdb --all %s%s\n", ECHO_QUOTE,
	/* Did we copy the free space files? */
			(GET_MAJOR_VERSION(old_cluster.major_version) >= 804) ?
			"--analyze-only" : "--analyze", ECHO_QUOTE);
	fprintf(script, "echo\n\n");

#ifndef WIN32
	fprintf(script, "sleep 2\n");
	fprintf(script, "PGOPTIONS='-c default_statistics_target=1 -c vacuum_cost_delay=0'\n");
	/* only need to export once */
	fprintf(script, "export PGOPTIONS\n");
#else
	fprintf(script, "REM simulate sleep 2\n");
	fprintf(script, "PING 1.1.1.1 -n 1 -w 2000 > nul\n");
	fprintf(script, "SET PGOPTIONS=-c default_statistics_target=1 -c vacuum_cost_delay=0\n");
#endif

	fprintf(script, "echo %sGenerating minimal optimizer statistics (1 target)%s\n",
			ECHO_QUOTE, ECHO_QUOTE);
	fprintf(script, "echo %s--------------------------------------------------%s\n",
			ECHO_QUOTE, ECHO_QUOTE);
	fprintf(script, "vacuumdb --all --analyze-only\n");
	fprintf(script, "echo\n");
	fprintf(script, "echo %sThe server is now available with minimal optimizer statistics.%s\n",
			ECHO_QUOTE, ECHO_QUOTE);
	fprintf(script, "echo %sQuery performance will be optimal once this script completes.%s\n",
			ECHO_QUOTE, ECHO_QUOTE);
	fprintf(script, "echo\n\n");

#ifndef WIN32
	fprintf(script, "sleep 2\n");
	fprintf(script, "PGOPTIONS='-c default_statistics_target=10'\n");
#else
	fprintf(script, "REM simulate sleep\n");
	fprintf(script, "PING 1.1.1.1 -n 1 -w 2000 > nul\n");
	fprintf(script, "SET PGOPTIONS=-c default_statistics_target=10\n");
#endif

	fprintf(script, "echo %sGenerating medium optimizer statistics (10 targets)%s\n",
			ECHO_QUOTE, ECHO_QUOTE);
	fprintf(script, "echo %s---------------------------------------------------%s\n",
			ECHO_QUOTE, ECHO_QUOTE);
	fprintf(script, "vacuumdb --all --analyze-only\n");
	fprintf(script, "echo\n\n");

#ifndef WIN32
	fprintf(script, "unset PGOPTIONS\n");
#else
	fprintf(script, "SET PGOPTIONS\n");
#endif

	fprintf(script, "echo %sGenerating default (full) optimizer statistics (100 targets?)%s\n",
//.........这里部分代码省略.........

//.........这里部分代码省略.........
				)
			{
				/*
				 * It's a symbolic link in source, but not in target.
				 * Strange..
				 */
				pg_fatal("\"%s\" is not a symbolic link\n", localpath);
			}

			if (!exists)
				action = FILE_ACTION_CREATE;
			else
				action = FILE_ACTION_NONE;
			oldsize = 0;
			break;

		case FILE_TYPE_REGULAR:
			if (exists && !S_ISREG(statbuf.st_mode))
				pg_fatal("\"%s\" is not a regular file\n", localpath);

			if (!exist