pg_upgrade: Move live_check variable to user_opts.

At the moment, pg_upgrade stores whether it is doing a "live check"
(i.e., the user specified --check and the old server is still
running) in a local variable scoped to main().  This live_check
variable is passed to several functions.  To further complicate
matters, a few call sites provide a hard-coded "false" as the
live_check argument.  Specifically, this is done when calling these
functions for the new cluster, for which any live-check-only paths
won't apply.

This commit moves the live_check variable to the global user_opts
variable, which stores information about the options the user
specified on the command line.  This allows us to remove the
live_check parameter from several functions.  For the functions
with callers that provide a hard-coded "false" as the live_check
argument (e.g., get_control_data()), we verify the given cluster is
the old cluster before taking any live-check-only paths.

This small refactoring effort helps simplify some proposed changes
that would parallelize many of pg_upgrade's once-in-each-database
tasks using libpq's asynchronous APIs.  By removing the live_check
parameter, we can more easily convert the functions to callbacks
for the new parallel system.

Reviewed-by: Daniel Gustafsson
Discussion: https://postgr.es/m/20240516211638.GA1688936%40nathanxps13

src/bin/pg_upgrade/check.c

@@ -29,7 +29,7 @@ static void check_for_new_tablespace_dir(void);
 static void check_for_user_defined_encoding_conversions(ClusterInfo *cluster);
 static void check_new_cluster_logical_replication_slots(void);
 static void check_new_cluster_subscription_configuration(void);
-static void check_old_cluster_for_valid_slots(bool live_check);
+static void check_old_cluster_for_valid_slots(void);
 static void check_old_cluster_subscription_state(void);
 
 /*
@@ -555,9 +555,9 @@ fix_path_separator(char *path)
 }
 
 void
-output_check_banner(bool live_check)
+output_check_banner(void)
 {
-	if (user_opts.check && live_check)
+	if (user_opts.live_check)
 	{
 		pg_log(PG_REPORT,
 			   "Performing Consistency Checks on Old Live Server\n"
@@ -573,18 +573,18 @@ output_check_banner(bool live_check)
 
 
 void
-check_and_dump_old_cluster(bool live_check)
+check_and_dump_old_cluster(void)
 {
 	/* -- OLD -- */
 
-	if (!live_check)
+	if (!user_opts.live_check)
 		start_postmaster(&old_cluster, true);
 
 	/*
 	 * Extract a list of databases, tables, and logical replication slots from
 	 * the old cluster.
 	 */
-	get_db_rel_and_slot_infos(&old_cluster, live_check);
+	get_db_rel_and_slot_infos(&old_cluster);
 
 	init_tablespaces();
 
@@ -605,7 +605,7 @@ check_and_dump_old_cluster(bool live_check)
 		 * Logical replication slots can be migrated since PG17. See comments
 		 * atop get_old_cluster_logical_slot_infos().
 		 */
-		check_old_cluster_for_valid_slots(live_check);
+		check_old_cluster_for_valid_slots();
 
 		/*
 		 * Subscriptions and their dependencies can be migrated since PG17.
@@ -669,7 +669,7 @@ check_and_dump_old_cluster(bool live_check)
 	if (!user_opts.check)
 		generate_old_dump();
 
-	if (!live_check)
+	if (!user_opts.live_check)
 		stop_postmaster(false);
 }
 
@@ -677,7 +677,7 @@ check_and_dump_old_cluster(bool live_check)
 void
 check_new_cluster(void)
 {
-	get_db_rel_and_slot_infos(&new_cluster, false);
+	get_db_rel_and_slot_infos(&new_cluster);
 
 	check_new_cluster_is_empty();
 
@@ -828,14 +828,14 @@ check_cluster_versions(void)
 
 
 void
-check_cluster_compatibility(bool live_check)
+check_cluster_compatibility(void)
 {
 	/* get/check pg_control data of servers */
-	get_control_data(&old_cluster, live_check);
-	get_control_data(&new_cluster, false);
+	get_control_data(&old_cluster);
+	get_control_data(&new_cluster);
 	check_control_data(&old_cluster.controldata, &new_cluster.controldata);
 
-	if (live_check && old_cluster.port == new_cluster.port)
+	if (user_opts.live_check && old_cluster.port == new_cluster.port)
 		pg_fatal("When checking a live server, "
 				 "the old and new port numbers must be different.");
 }
@@ -1838,7 +1838,7 @@ check_new_cluster_subscription_configuration(void)
  * before shutdown.
  */
 static void
-check_old_cluster_for_valid_slots(bool live_check)
+check_old_cluster_for_valid_slots(void)
 {
 	char		output_path[MAXPGPATH];
 	FILE	   *script = NULL;
@@ -1877,7 +1877,7 @@ check_old_cluster_for_valid_slots(bool live_check)
 			 * Note: This can be satisfied only when the old cluster has been
 			 * shut down, so we skip this for live checks.
 			 */
-			if (!live_check && !slot->caught_up)
+			if (!user_opts.live_check && !slot->caught_up)
 			{
 				if (script == NULL &&
 					(script = fopen_priv(output_path, "w")) == NULL)

src/bin/pg_upgrade/controldata.c

@@ -33,7 +33,7 @@
  * return valid xid data for a running server.
  */
 void
-get_control_data(ClusterInfo *cluster, bool live_check)
+get_control_data(ClusterInfo *cluster)
 {
 	char		cmd[MAXPGPATH];
 	char		bufin[MAX_STRING];
@@ -76,6 +76,7 @@ get_control_data(ClusterInfo *cluster, bool live_check)
 	uint32		segno = 0;
 	char	   *resetwal_bin;
 	int			rc;
+	bool		live_check = (cluster == &old_cluster && user_opts.live_check);
 
 	/*
 	 * Because we test the pg_resetwal output as strings, it has to be in

src/bin/pg_upgrade/info.c

@@ -27,7 +27,7 @@ static void free_rel_infos(RelInfoArr *rel_arr);
 static void print_db_infos(DbInfoArr *db_arr);
 static void print_rel_infos(RelInfoArr *rel_arr);
 static void print_slot_infos(LogicalSlotInfoArr *slot_arr);
-static void get_old_cluster_logical_slot_infos(DbInfo *dbinfo, bool live_check);
+static void get_old_cluster_logical_slot_infos(DbInfo *dbinfo);
 
 
 /*
@@ -272,11 +272,9 @@ report_unmatched_relation(const RelInfo *rel, const DbInfo *db, bool is_new_db)
  *
  * higher level routine to generate dbinfos for the database running
  * on the given "port". Assumes that server is already running.
- *
- * live_check would be used only when the target is the old cluster.
  */
 void
-get_db_rel_and_slot_infos(ClusterInfo *cluster, bool live_check)
+get_db_rel_and_slot_infos(ClusterInfo *cluster)
 {
 	int			dbnum;
 
@@ -293,7 +291,7 @@ get_db_rel_and_slot_infos(ClusterInfo *cluster, bool live_check)
 		get_rel_infos(cluster, pDbInfo);
 
 		if (cluster == &old_cluster)
-			get_old_cluster_logical_slot_infos(pDbInfo, live_check);
+			get_old_cluster_logical_slot_infos(pDbInfo);
 	}
 
 	if (cluster == &old_cluster)
@@ -637,7 +635,7 @@ get_rel_infos(ClusterInfo *cluster, DbInfo *dbinfo)
  * are included.
  */
 static void
-get_old_cluster_logical_slot_infos(DbInfo *dbinfo, bool live_check)
+get_old_cluster_logical_slot_infos(DbInfo *dbinfo)
 {
 	PGconn	   *conn;
 	PGresult   *res;
@@ -673,7 +671,7 @@ get_old_cluster_logical_slot_infos(DbInfo *dbinfo, bool live_check)
 							"WHERE slot_type = 'logical' AND "
 							"database = current_database() AND "
 							"temporary IS FALSE;",
-							live_check ? "FALSE" :
+							user_opts.live_check ? "FALSE" :
 							"(CASE WHEN invalidation_reason IS NOT NULL THEN FALSE "
 							"ELSE (SELECT pg_catalog.binary_upgrade_logical_slot_has_caught_up(slot_name)) "
 							"END)");

src/bin/pg_upgrade/option.c

@@ -470,10 +470,10 @@ adjust_data_dir(ClusterInfo *cluster)
  * directory.
  */
 void
-get_sock_dir(ClusterInfo *cluster, bool live_check)
+get_sock_dir(ClusterInfo *cluster)
 {
 #if !defined(WIN32)
-	if (!live_check)
+	if (!user_opts.live_check || cluster == &new_cluster)
 		cluster->sockdir = user_opts.socketdir;
 	else
 	{

src/bin/pg_upgrade/pg_upgrade.c

@@ -65,7 +65,7 @@ static void create_new_objects(void);
 static void copy_xact_xlog_xid(void);
 static void set_frozenxids(bool minmxid_only);
 static void make_outputdirs(char *pgdata);
-static void setup(char *argv0, bool *live_check);
+static void setup(char *argv0);
 static void create_logical_replication_slots(void);
 
 ClusterInfo old_cluster,
@@ -88,7 +88,6 @@ int
 main(int argc, char **argv)
 {
 	char	   *deletion_script_file_name = NULL;
-	bool		live_check = false;
 
 	/*
 	 * pg_upgrade doesn't currently use common/logging.c, but initialize it
@@ -123,18 +122,18 @@ main(int argc, char **argv)
 	 */
 	make_outputdirs(new_cluster.pgdata);
 
-	setup(argv[0], &live_check);
+	setup(argv[0]);
 
-	output_check_banner(live_check);
+	output_check_banner();
 
 	check_cluster_versions();
 
-	get_sock_dir(&old_cluster, live_check);
-	get_sock_dir(&new_cluster, false);
+	get_sock_dir(&old_cluster);
+	get_sock_dir(&new_cluster);
 
-	check_cluster_compatibility(live_check);
+	check_cluster_compatibility();
 
-	check_and_dump_old_cluster(live_check);
+	check_and_dump_old_cluster();
 
 
 	/* -- NEW -- */
@@ -331,7 +330,7 @@ make_outputdirs(char *pgdata)
 
 
 static void
-setup(char *argv0, bool *live_check)
+setup(char *argv0)
 {
 	/*
 	 * make sure the user has a clean environment, otherwise, we may confuse
@@ -378,7 +377,7 @@ setup(char *argv0, bool *live_check)
 				pg_fatal("There seems to be a postmaster servicing the old cluster.\n"
 						 "Please shutdown that postmaster and try again.");
 			else
-				*live_check = true;
+				user_opts.live_check = true;
 		}
 	}
 
@@ -660,7 +659,7 @@ create_new_objects(void)
 		set_frozenxids(true);
 
 	/* update new_cluster info now that we have objects in the databases */
-	get_db_rel_and_slot_infos(&new_cluster, false);
+	get_db_rel_and_slot_infos(&new_cluster);
 }
 
 /*

src/bin/pg_upgrade/pg_upgrade.h

@@ -321,6 +321,7 @@ typedef struct
 typedef struct
 {
 	bool		check;			/* check clusters only, don't change any data */
+	bool		live_check;		/* check clusters only, old server is running */
 	bool		do_sync;		/* flush changes to disk */
 	transferMode transfer_mode; /* copy files or link them? */
 	int			jobs;			/* number of processes/threads to use */
@@ -365,20 +366,20 @@ extern OSInfo os_info;
 
 /* check.c */
 
-void		output_check_banner(bool live_check);
-void		check_and_dump_old_cluster(bool live_check);
+void		output_check_banner(void);
+void		check_and_dump_old_cluster(void);
 void		check_new_cluster(void);
 void		report_clusters_compatible(void);
 void		issue_warnings_and_set_wal_level(void);
 void		output_completion_banner(char *deletion_script_file_name);
 void		check_cluster_versions(void);
-void		check_cluster_compatibility(bool live_check);
+void		check_cluster_compatibility(void);
 void		create_script_for_old_cluster_deletion(char **deletion_script_file_name);
 
 
 /* controldata.c */
 
-void		get_control_data(ClusterInfo *cluster, bool live_check);
+void		get_control_data(ClusterInfo *cluster);
 void		check_control_data(ControlData *oldctrl, ControlData *newctrl);
 void		disable_old_cluster(void);
 
@@ -427,7 +428,7 @@ void		check_loadable_libraries(void);
 FileNameMap *gen_db_file_maps(DbInfo *old_db,
 							  DbInfo *new_db, int *nmaps, const char *old_pgdata,
 							  const char *new_pgdata);
-void		get_db_rel_and_slot_infos(ClusterInfo *cluster, bool live_check);
+void		get_db_rel_and_slot_infos(ClusterInfo *cluster);
 int			count_old_cluster_logical_slots(void);
 void		get_subscription_count(ClusterInfo *cluster);
 
@@ -435,7 +436,7 @@ void		get_subscription_count(ClusterInfo *cluster);
 
 void		parseCommandLine(int argc, char *argv[]);
 void		adjust_data_dir(ClusterInfo *cluster);
-void		get_sock_dir(ClusterInfo *cluster, bool live_check);
+void		get_sock_dir(ClusterInfo *cluster);
 
 /* relfilenumber.c */