Centralize effective_cache_size default setting

src/backend/bootstrap/bootstrap.c

@@ -350,8 +350,6 @@ AuxiliaryProcessMain(int argc, char *argv[])
 			proc_exit(1);
 	}
 
-	set_default_effective_cache_size();
-	
 	/* Validate we have been given a reasonable-looking DataDir */
 	Assert(DataDir);
 	ValidatePgVersion(DataDir);

src/backend/postmaster/postmaster.c

@@ -785,8 +785,6 @@ PostmasterMain(int argc, char *argv[])
 	if (!SelectConfigFiles(userDoption, progname))
 		ExitPostmaster(2);
 
-	set_default_effective_cache_size();
-
 	if (output_config_variable != NULL)
 	{
 		/*

src/backend/tcop/postgres.c

@@ -3592,8 +3592,6 @@ PostgresMain(int argc, char *argv[],
 			proc_exit(1);
 	}
 
-	set_default_effective_cache_size();
-	    
 	/*
 	 * You might expect to see a setsid() call here, but it's not needed,
 	 * because if we are under a postmaster then BackendInitialize() did it.

src/backend/utils/misc/guc.c

@@ -4238,6 +4238,8 @@ SelectConfigFiles(const char *userDoption, const char *progname)
 	 */
 	pg_timezone_abbrev_initialize();
 
+	set_default_effective_cache_size();
+	    
 	/*
 	 * Figure out where pg_hba.conf is, and make sure the path is absolute.
 	 */