postgresql/contrib/pg_upgrade/check.c

/*
 *	check.c
 *
 *	server checks and output routines
 *
 *	Copyright (c) 2010-2011, PostgreSQL Global Development Group
 *	contrib/pg_upgrade/check.c
 */

#include "postgres.h"

#include "pg_upgrade.h"


static void set_locale_and_encoding(ClusterInfo *cluster);
static void check_new_cluster_is_empty(void);
static void check_locale_and_encoding(ControlData *oldctrl,
						  ControlData *newctrl);
static void check_is_super_user(ClusterInfo *cluster);
static void check_for_prepared_transactions(ClusterInfo *cluster);
static void check_for_isn_and_int8_passing_mismatch(ClusterInfo *cluster);
static void check_for_reg_data_type_usage(ClusterInfo *cluster);
static void check_for_support_lib(ClusterInfo *cluster);
static void get_bin_version(ClusterInfo *cluster);


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");
	}
}


void
check_old_cluster(bool live_check, char **sequence_script_file_name)
{
	/* -- OLD -- */

	if (!live_check)
		start_postmaster(&old_cluster);

	set_locale_and_encoding(&old_cluster);

	get_pg_database_relfilenode(&old_cluster);

	/* Extract a list of databases and tables from the old cluster */
	get_db_and_rel_infos(&old_cluster);

	init_tablespaces();

	get_loadable_libraries();


	/*
	 * Check for various failure cases
	 */
	check_is_super_user(&old_cluster);
	check_for_prepared_transactions(&old_cluster);
	check_for_reg_data_type_usage(&old_cluster);
	check_for_isn_and_int8_passing_mismatch(&old_cluster);

	/* old = PG 8.3 checks? */
	if (GET_MAJOR_VERSION(old_cluster.major_version) <= 803)
	{
		old_8_3_check_for_name_data_type_usage(&old_cluster);
		old_8_3_check_for_tsquery_usage(&old_cluster);
		old_8_3_check_ltree_usage(&old_cluster);
		if (user_opts.check)
		{
			old_8_3_rebuild_tsvector_tables(&old_cluster, true);
			old_8_3_invalidate_hash_gin_indexes(&old_cluster, true);
			old_8_3_invalidate_bpchar_pattern_ops_indexes(&old_cluster, true);
		}
		else

			/*
			 * While we have the old server running, create the script to
			 * properly restore its sequence values but we report this at the
			 * end.
			 */
			*sequence_script_file_name =
				old_8_3_create_sequence_script(&old_cluster);
	}

	/* Pre-PG 9.0 had no large object permissions */
	if (GET_MAJOR_VERSION(old_cluster.major_version) <= 804)
		new_9_0_populate_pg_largeobject_metadata(&old_cluster, true);

	/*
	 * While not a check option, we do this now because this is the only time
	 * the old server is running.
	 */
	if (!user_opts.check)
	{
		generate_old_dump();
		split_old_dump();
	}

	if (!live_check)
		stop_postmaster(false);
}


void
check_new_cluster(void)
{
	set_locale_and_encoding(&new_cluster);

	get_db_and_rel_infos(&new_cluster);

	check_new_cluster_is_empty();
	check_for_prepared_transactions(&new_cluster);

	check_loadable_libraries();

	check_locale_and_encoding(&old_cluster.controldata, &new_cluster.controldata);

	if (user_opts.transfer_mode == TRANSFER_MODE_LINK)
		check_hard_link();
}


void
report_clusters_compatible(void)
{
	if (user_opts.check)
	{
		pg_log(PG_REPORT, "\n*Clusters are compatible*\n");
		/* stops new cluster */
		stop_postmaster(false);
		exit(0);
	}

	pg_log(PG_REPORT, "\n"
		   "If pg_upgrade fails after this point, you must re-initdb the new cluster\n"
		   "before continuing.  You will also need to remove the \".old\" suffix from\n"
		   "%s/global/pg_control.old.\n", old_cluster.pgdata);
}


void
issue_warnings(char *sequence_script_file_name)
{
	/* old = PG 8.3 warnings? */
	if (GET_MAJOR_VERSION(old_cluster.major_version) <= 803)
	{
		start_postmaster(&new_cluster);

		/* restore proper sequence values using file created from old server */
		if (sequence_script_file_name)
		{
			prep_status("Adjusting sequences");
			exec_prog(true,
					  SYSTEMQUOTE "\"%s/psql\" --set ON_ERROR_STOP=on "
					  "--no-psqlrc --port %d --username \"%s\" "
					  "-f \"%s\" --dbname template1 >> \"%s\"" SYSTEMQUOTE,
					  new_cluster.bindir, new_cluster.port, os_info.user,
					  sequence_script_file_name, log_opts.filename2);
			unlink(sequence_script_file_name);
			check_ok();
		}

		old_8_3_rebuild_tsvector_tables(&new_cluster, false);
		old_8_3_invalidate_hash_gin_indexes(&new_cluster, false);
		old_8_3_invalidate_bpchar_pattern_ops_indexes(&new_cluster, false);
		stop_postmaster(false);
	}

	/* Create dummy large object permissions for old < PG 9.0? */
	if (GET_MAJOR_VERSION(old_cluster.major_version) <= 804)
	{
		start_postmaster(&new_cluster);
		new_9_0_populate_pg_largeobject_metadata(&new_cluster, false);
		stop_postmaster(false);
	}
}


void
output_completion_banner(char *deletion_script_file_name)
{
	/* Did we copy the free space files? */
	if (GET_MAJOR_VERSION(old_cluster.major_version) >= 804)
		pg_log(PG_REPORT,
			   "Optimizer statistics are not transferred by pg_upgrade so consider\n"
			   "running:\n"
			   "    vacuumdb --all --analyze-only\n"
			   "on the newly-upgraded cluster.\n\n");
	else
		pg_log(PG_REPORT,
			   "Optimizer statistics and free space information are not transferred\n"
			   "by pg_upgrade so consider running:\n"
			   "    vacuumdb --all --analyze\n"
			   "on the newly-upgraded cluster.\n\n");

	pg_log(PG_REPORT,
		   "Running this script will delete the old cluster's data files:\n"
		   "    %s\n",
		   deletion_script_file_name);
}


void
check_cluster_versions(void)
{
	prep_status("Checking cluster versions");

	/* get old and new cluster versions */
	old_cluster.major_version = get_major_server_version(&old_cluster);
	new_cluster.major_version = get_major_server_version(&new_cluster);

	/*
	 * We allow upgrades from/to the same major version for alpha/beta
	 * upgrades
	 */

	if (GET_MAJOR_VERSION(old_cluster.major_version) < 803)
		pg_log(PG_FATAL, "This utility can only upgrade from PostgreSQL version 8.3 and later.\n");

	/* Only current PG version is supported as a target */
	if (GET_MAJOR_VERSION(new_cluster.major_version) != GET_MAJOR_VERSION(PG_VERSION_NUM))
		pg_log(PG_FATAL, "This utility can only upgrade to PostgreSQL version %s.\n",
			   PG_MAJORVERSION);

	/*
	 * We can't allow downgrading because we use the target pg_dumpall, and
	 * pg_dumpall cannot operate on new database versions, only older versions.
	 */
	if (old_cluster.major_version > new_cluster.major_version)
		pg_log(PG_FATAL, "This utility cannot be used to downgrade to older major PostgreSQL versions.\n");

	/* get old and new binary versions */
	get_bin_version(&old_cluster);
	get_bin_version(&new_cluster);

	/* Ensure binaries match the designated data directories */
	if (GET_MAJOR_VERSION(old_cluster.major_version) !=
		GET_MAJOR_VERSION(old_cluster.bin_version))
		pg_log(PG_FATAL,
			   "Old cluster data and binary directories are from different major versions.\n");
	if (GET_MAJOR_VERSION(new_cluster.major_version) !=
		GET_MAJOR_VERSION(new_cluster.bin_version))
		pg_log(PG_FATAL,
			   "New cluster data and binary directories are from different major versions.\n");

	check_ok();
}


void
check_cluster_compatibility(bool live_check)
{
	check_for_support_lib(&new_cluster);

	/* get/check pg_control data of servers */
	get_control_data(&old_cluster, live_check);
	get_control_data(&new_cluster, false);
	check_control_data(&old_cluster.controldata, &new_cluster.controldata);

	/* Is it 9.0 but without tablespace directories? */
	if (GET_MAJOR_VERSION(new_cluster.major_version) == 900 &&
		new_cluster.controldata.cat_ver < TABLE_SPACE_SUBDIRS_CAT_VER)
		pg_log(PG_FATAL, "This utility can only upgrade to PostgreSQL version 9.0 after 2010-01-11\n"
			   "because of backend API changes made during development.\n");
}


/*
 * set_locale_and_encoding()
 *
 * query the database to get the template0 locale
 */
static void
set_locale_and_encoding(ClusterInfo *cluster)
{
	ControlData *ctrl = &cluster->controldata;
	PGconn	   *conn;
	PGresult   *res;
	int			i_encoding;
	int			cluster_version = cluster->major_version;

	conn = connectToServer(cluster, "template1");

	/* for pg < 80400, we got the values from pg_controldata */
	if (cluster_version >= 80400)
	{
		int			i_datcollate;
		int			i_datctype;

		res = executeQueryOrDie(conn,
								"SELECT datcollate, datctype "
								"FROM 	pg_catalog.pg_database "
								"WHERE	datname = 'template0' ");
		assert(PQntuples(res) == 1);

		i_datcollate = PQfnumber(res, "datcollate");
		i_datctype = PQfnumber(res, "datctype");

		ctrl->lc_collate = pg_strdup(PQgetvalue(res, 0, i_datcollate));
		ctrl->lc_ctype = pg_strdup(PQgetvalue(res, 0, i_datctype));

		PQclear(res);
	}

	res = executeQueryOrDie(conn,
							"SELECT pg_catalog.pg_encoding_to_char(encoding) "
							"FROM 	pg_catalog.pg_database "
							"WHERE	datname = 'template0' ");
	assert(PQntuples(res) == 1);

	i_encoding = PQfnumber(res, "pg_encoding_to_char");
	ctrl->encoding = pg_strdup(PQgetvalue(res, 0, i_encoding));

	PQclear(res);

	PQfinish(conn);
}


/*
 * check_locale_and_encoding()
 *
 *	locale is not in pg_controldata in 8.4 and later so
 *	we probably had to get via a database query.
 */
static void
check_locale_and_encoding(ControlData *oldctrl,
						  ControlData *newctrl)
{
	/* These are often defined with inconsistent case, so use pg_strcasecmp(). */
	if (pg_strcasecmp(oldctrl->lc_collate, newctrl->lc_collate) != 0)
		pg_log(PG_FATAL,
			   "old and new cluster lc_collate values do not match\n");
	if (pg_strcasecmp(oldctrl->lc_ctype, newctrl->lc_ctype) != 0)
		pg_log(PG_FATAL,
			   "old and new cluster lc_ctype values do not match\n");
	if (pg_strcasecmp(oldctrl->encoding, newctrl->encoding) != 0)
		pg_log(PG_FATAL,
			   "old and new cluster encoding values do not match\n");
}


static void
check_new_cluster_is_empty(void)
{
	int			dbnum;

	for (dbnum = 0; dbnum < new_cluster.dbarr.ndbs; dbnum++)
	{
		int			relnum;
		RelInfoArr *rel_arr = &new_cluster.dbarr.dbs[dbnum].rel_arr;

		for (relnum = 0; relnum < rel_arr->nrels;
			 relnum++)
		{
			/* pg_largeobject and its index should be skipped */
			if (strcmp(rel_arr->rels[relnum].nspname, "pg_catalog") != 0)
				pg_log(PG_FATAL, "New cluster database \"%s\" is not empty\n",
					   new_cluster.dbarr.dbs[dbnum].db_name);
		}
	}

}


/*
 * create_script_for_old_cluster_deletion()
 *
 *	This is particularly useful for tablespace deletion.
 */
void
create_script_for_old_cluster_deletion(char **deletion_script_file_name)
{
	FILE	   *script = NULL;
	int			tblnum;

	*deletion_script_file_name = pg_malloc(MAXPGPATH);

	prep_status("Creating script to delete old cluster");

	snprintf(*deletion_script_file_name, MAXPGPATH, "%s/delete_old_cluster.%s",
			 os_info.cwd, SCRIPT_EXT);

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

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

	/* delete old cluster's default tablespace */
	fprintf(script, RMDIR_CMD " %s\n", old_cluster.pgdata);

	/* delete old cluster's alternate tablespaces */
	for (tblnum = 0; tblnum < os_info.num_tablespaces; tblnum++)
	{
		/*
		 * Do the old cluster's per-database directories share a directory
		 * with a new version-specific tablespace?
		 */
		if (strlen(old_cluster.tablespace_suffix) == 0)
		{
			/* delete per-database directories */
			int			dbnum;

			fprintf(script, "\n");
			/* remove PG_VERSION? */
			if (GET_MAJOR_VERSION(old_cluster.major_version) <= 804)
				fprintf(script, RM_CMD " %s%s/PG_VERSION\n",
				 os_info.tablespaces[tblnum], old_cluster.tablespace_suffix);

			for (dbnum = 0; dbnum < old_cluster.dbarr.ndbs; dbnum++)
			{
				fprintf(script, RMDIR_CMD " %s%s/%d\n",
				  os_info.tablespaces[tblnum], old_cluster.tablespace_suffix,
						old_cluster.dbarr.dbs[dbnum].db_oid);
			}
		}
		else

			/*
			 * Simply delete the tablespace directory, which might be ".old"
			 * or a version-specific subdirectory.
			 */
			fprintf(script, RMDIR_CMD " %s%s\n",
				 os_info.tablespaces[tblnum], old_cluster.tablespace_suffix);
	}

	fclose(script);

#ifndef WIN32
	if (chmod(*deletion_script_file_name, S_IRWXU) != 0)
		pg_log(PG_FATAL, "Could not add execute permission to file \"%s\": %s\n",
			   *deletion_script_file_name, getErrorText(errno));
#endif

	check_ok();
}


/*
 *	check_is_super_user()
 *
 *	Make sure we are the super-user.
 */
static void
check_is_super_user(ClusterInfo *cluster)
{
	PGresult   *res;
	PGconn	   *conn = connectToServer(cluster, "template1");

	prep_status("Checking database user is a superuser");

	/* Can't use pg_authid because only superusers can view it. */
	res = executeQueryOrDie(conn,
							"SELECT rolsuper "
							"FROM pg_catalog.pg_roles "
							"WHERE rolname = current_user");

	if (PQntuples(res) != 1 || strcmp(PQgetvalue(res, 0, 0), "t") != 0)
		pg_log(PG_FATAL, "database user \"%s\" is not a superuser\n",
			   os_info.user);

	PQclear(res);

	PQfinish(conn);

	check_ok();
}


/*
 *	check_for_prepared_transactions()
 *
 *	Make sure there are no prepared transactions because the storage format
 *	might have changed.
 */
static void
check_for_prepared_transactions(ClusterInfo *cluster)
{
	PGresult   *res;
	PGconn	   *conn = connectToServer(cluster, "template1");

	prep_status("Checking for prepared transactions");

	res = executeQueryOrDie(conn,
							"SELECT * "
							"FROM pg_catalog.pg_prepared_xacts");

	if (PQntuples(res) != 0)
		pg_log(PG_FATAL, "The %s cluster contains prepared transactions\n",
			   CLUSTER_NAME(cluster));

	PQclear(res);

	PQfinish(conn);

	check_ok();
}


/*
 *	check_for_isn_and_int8_passing_mismatch()
 *
 *	contrib/isn relies on data type int8, and in 8.4 int8 can now be passed
 *	by value.  The schema dumps the CREATE TYPE PASSEDBYVALUE setting so
 *	it must match for the old and new servers.
 */
static void
check_for_isn_and_int8_passing_mismatch(ClusterInfo *cluster)
{
	int			dbnum;
	FILE	   *script = NULL;
	bool		found = false;
	char		output_path[MAXPGPATH];

	prep_status("Checking for contrib/isn with bigint-passing mismatch");

	if (old_cluster.controldata.float8_pass_by_value ==
		new_cluster.controldata.float8_pass_by_value)
	{
		/* no mismatch */
		check_ok();
		return;
	}

	snprintf(output_path, sizeof(output_path), "%s/contrib_isn_and_int8_pass_by_value.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_proname;
		DbInfo	   *active_db = &cluster->dbarr.dbs[dbnum];
		PGconn	   *conn = connectToServer(cluster, active_db->db_name);

		/* Find any functions coming from contrib/isn */
		res = executeQueryOrDie(conn,
								"SELECT n.nspname, p.proname "
								"FROM	pg_catalog.pg_proc p, "
								"		pg_catalog.pg_namespace n "
								"WHERE	p.pronamespace = n.oid AND "
								"		p.probin = '$libdir/isn'");

		ntups = PQntuples(res);
		i_nspname = PQfnumber(res, "nspname");
		i_proname = PQfnumber(res, "proname");
		for (rowno = 0; rowno < ntups; rowno++)
		{
			found = true;
			if (script == NULL && (script = fopen(output_path, "w")) == NULL)
				pg_log(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\n",
					PQgetvalue(res, rowno, i_nspname),
					PQgetvalue(res, rowno, i_proname));
		}

		PQclear(res);

		PQfinish(conn);
	}

	if (script)
		fclose(script);

	if (found)
	{
		pg_log(PG_REPORT, "fatal\n");
		pg_log(PG_FATAL,
			   "Your installation contains \"contrib/isn\" functions which rely on the\n"
			   "bigint data type.  Your old and new clusters pass bigint values\n"
			   "differently so this cluster cannot currently be upgraded.  You can\n"
			   "manually upgrade databases that use \"contrib/isn\" facilities and remove\n"
			   "\"contrib/isn\" from the old cluster and restart the upgrade.  A list of\n"
			   "the problem functions is in the file:\n"
			   "    %s\n\n", output_path);
	}
	else
		check_ok();
}


/*
 * 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[MAXPGPATH];

	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 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_log(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();
}


/*
 * Test pg_upgrade_support.so is in the proper place.	 We cannot copy it
 * ourselves because install directories are typically root-owned.
 */
static void
check_for_support_lib(ClusterInfo *cluster)
{
	char		cmd[MAXPGPATH];
	char		libdir[MAX_STRING];
	char		libfile[MAXPGPATH];
	FILE	   *lib_test;
	FILE	   *output;

	snprintf(cmd, sizeof(cmd), "\"%s/pg_config\" --pkglibdir", cluster->bindir);

	if ((output = popen(cmd, "r")) == NULL ||
		fgets(libdir, sizeof(libdir), output) == NULL)
		pg_log(PG_FATAL, "Could not get pkglibdir data using %s: %s\n",
			   cmd, getErrorText(errno));


	pclose(output);

	/* Remove trailing newline */
	if (strchr(libdir, '\n') != NULL)
		*strchr(libdir, '\n') = '\0';

	snprintf(libfile, sizeof(libfile), "%s/pg_upgrade_support%s", libdir,
			 DLSUFFIX);

	if ((lib_test = fopen(libfile, "r")) == NULL)
		pg_log(PG_FATAL,
			   "The pg_upgrade_support module must be created and installed in the %s cluster.\n",
				CLUSTER_NAME(cluster));

	fclose(lib_test);
}


static void
get_bin_version(ClusterInfo *cluster)
{
	char		cmd[MAXPGPATH], cmd_output[MAX_STRING];
	FILE	   *output;
	int			pre_dot, post_dot;

	snprintf(cmd, sizeof(cmd), "\"%s/pg_ctl\" --version", cluster->bindir);

	if ((output = popen(cmd, "r")) == NULL ||
		fgets(cmd_output, sizeof(cmd_output), output) == NULL)
		pg_log(PG_FATAL, "Could not get pg_ctl version data using %s: %s\n",
			   cmd, getErrorText(errno));

	pclose(output);

	/* Remove trailing newline */
	if (strchr(cmd_output, '\n') != NULL)
		*strchr(cmd_output, '\n') = '\0';

	if (sscanf(cmd_output, "%*s %*s %d.%d", &pre_dot, &post_dot) != 2)
		pg_log(PG_FATAL, "could not get version from %s\n", cmd);

	cluster->bin_version = (pre_dot * 100 + post_dot) * 100;
}