process startup: Remove bootstrap / checker modes from AuxProcType.

Neither is actually initialized as an auxiliary process, so it does not really
make sense to reserve a PGPROC etc for them.

This keeps checker mode implemented by exiting partway through bootstrap
mode. That might be worth changing at some point, perhaps if we ever extend
checker mode to be a more general tool.

Author: Andres Freund <andres@anarazel.de>
Reviewed-By: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Reviewed-By: Robert Haas <robertmhaas@gmail.com>
Discussion: https://postgr.es/m/20210802164124.ufo5buo4apl6yuvs@alap3.anarazel.de

src/backend/bootstrap/bootstrap.c

@@ -193,9 +193,14 @@ CheckerModeMain(void)
  *	 The bootstrap mode is used to initialize the template database.
  *	 The bootstrap backend doesn't speak SQL, but instead expects
  *	 commands in a special bootstrap language.
+ *
+ *	 When check_only is true, startup is done only far enough to verify that
+ *	 the current configuration, particularly the passed in options pertaining
+ *	 to shared memory sizing, options work (or at least do not cause an error
+ *	 up to shared memory creation).
  */
 void
-BootstrapModeMain(int argc, char *argv[])
+BootstrapModeMain(int argc, char *argv[], bool check_only)
 {
 	int			i;
 	char	   *progname = argv[0];
@@ -209,16 +214,14 @@ BootstrapModeMain(int argc, char *argv[])
 	/* Set defaults, to be overridden by explicit options below */
 	InitializeGUCOptions();
 
-	/* an initial --boot should be present */
+	/* an initial --boot or --check should be present */
 	Assert(argc == 1
-		   || strcmp(argv[1], "--boot") != 0);
+		   || strcmp(argv[1], "--boot") != 0
+		   || strcmp(argv[1], "--check") != 0);
 	argv++;
 	argc--;
 
-	/* If no -x argument, we are a CheckerProcess */
-	MyAuxProcType = CheckerProcess;
-
-	while ((flag = getopt(argc, argv, "B:c:d:D:Fkr:x:X:-:")) != -1)
+	while ((flag = getopt(argc, argv, "B:c:d:D:Fkr:X:-:")) != -1)
 	{
 		switch (flag)
 		{
@@ -250,16 +253,6 @@ BootstrapModeMain(int argc, char *argv[])
 			case 'r':
 				strlcpy(OutputFileName, optarg, MAXPGPATH);
 				break;
-			case 'x':
-				MyAuxProcType = atoi(optarg);
-				if (MyAuxProcType != CheckerProcess &&
-					MyAuxProcType != BootstrapProcess)
-				{
-					ereport(ERROR,
-							(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-							 errmsg("-x %s is invalid", optarg)));
-				}
-				break;
 			case 'X':
 				{
 					int			WalSegSz = strtoul(optarg, NULL, 0);
@@ -338,7 +331,7 @@ BootstrapModeMain(int argc, char *argv[])
 	 * point. Right now it seems like it'd cause more code duplication than
 	 * it's worth.
 	 */
-	if (MyAuxProcType == CheckerProcess)
+	if (check_only)
 	{
 		SetProcessingMode(NormalProcessing);
 		CheckerModeMain();

src/backend/main/main.c

@@ -197,8 +197,10 @@ main(int argc, char *argv[])
 	pgwin32_signal_initialize();
 #endif
 
-	if (argc > 1 && strcmp(argv[1], "--boot") == 0)
-		BootstrapModeMain(argc, argv);	/* does not return */
+	if (argc > 1 && strcmp(argv[1], "--check") == 0)
+		BootstrapModeMain(argc, argv, true);
+	else if (argc > 1 && strcmp(argv[1], "--boot") == 0)
+		BootstrapModeMain(argc, argv, false);
 	else if (argc > 1 && strcmp(argv[1], "--describe-config") == 0)
 		GucInfoMain();			/* does not return */
 	else if (argc > 1 && strcmp(argv[1], "--single") == 0)
@@ -350,9 +352,9 @@ help(const char *progname)
 
 	printf(_("\nOptions for bootstrapping mode:\n"));
 	printf(_("  --boot             selects bootstrapping mode (must be first argument)\n"));
+	printf(_("  --check            selects check mode (must be first argument)\n"));
 	printf(_("  DBNAME             database name (mandatory argument in bootstrapping mode)\n"));
 	printf(_("  -r FILENAME        send stdout and stderr to given file\n"));
-	printf(_("  -x NUM             internal use\n"));
 
 	printf(_("\nPlease read the documentation for the complete list of run-time\n"
 			 "configuration settings and how to set them on the command line or in\n"

src/backend/postmaster/auxprocess.c

@@ -142,11 +142,6 @@ AuxiliaryProcessMain(AuxProcType auxtype)
 
 	switch (MyAuxProcType)
 	{
-		case CheckerProcess:
-		case BootstrapProcess:
-			pg_unreachable();
-			break;
-
 		case StartupProcess:
 			StartupProcessMain();
 			proc_exit(1);

src/bin/initdb/initdb.c

@@ -965,7 +965,7 @@ test_config_settings(void)
 		test_buffs = MIN_BUFS_FOR_CONNS(test_conns);
 
 		snprintf(cmd, sizeof(cmd),
-				 "\"%s\" --boot -x0 %s %s "
+				 "\"%s\" --check %s %s "
 				 "-c max_connections=%d "
 				 "-c shared_buffers=%d "
 				 "-c dynamic_shared_memory_type=%s "
@@ -1001,7 +1001,7 @@ test_config_settings(void)
 		}
 
 		snprintf(cmd, sizeof(cmd),
-				 "\"%s\" --boot -x0 %s %s "
+				 "\"%s\" --check %s %s "
 				 "-c max_connections=%d "
 				 "-c shared_buffers=%d "
 				 "-c dynamic_shared_memory_type=%s "
@@ -1406,7 +1406,7 @@ bootstrap_template1(void)
 	unsetenv("PGCLIENTENCODING");
 
 	snprintf(cmd, sizeof(cmd),
-			 "\"%s\" --boot -x1 -X %u %s %s %s %s",
+			 "\"%s\" --boot -X %u %s %s %s %s",
 			 backend_exec,
 			 wal_segment_size_mb * (1024 * 1024),
 			 data_checksums ? "-k" : "",

src/include/bootstrap/bootstrap.h

@@ -32,7 +32,7 @@ extern Form_pg_attribute attrtypes[MAXATTR];
 extern int	numattr;
 
 
-extern void BootstrapModeMain(int argc, char *argv[]) pg_attribute_noreturn();
+extern void BootstrapModeMain(int argc, char *argv[], bool check_only) pg_attribute_noreturn();
 
 extern void closerel(char *name);
 extern void boot_openrel(char *name);

src/include/miscadmin.h

@@ -427,9 +427,7 @@ extern ProcessingMode Mode;
 typedef enum
 {
 	NotAnAuxProcess = -1,
-	CheckerProcess = 0,
-	BootstrapProcess,
-	StartupProcess,
+	StartupProcess = 0,
 	BgWriterProcess,
 	ArchiverProcess,
 	CheckpointerProcess,
@@ -441,7 +439,6 @@ typedef enum
 
 extern AuxProcType MyAuxProcType;
 
-#define AmBootstrapProcess()		(MyAuxProcType == BootstrapProcess)
 #define AmStartupProcess()			(MyAuxProcType == StartupProcess)
 #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
 #define AmArchiverProcess()			(MyAuxProcType == ArchiverProcess)