Remove dead upgrade-mode 'U' option to postgres and postmaster.

src/backend/postmaster/postmaster.c

@@ -748,7 +748,7 @@ PostmasterMain(int argc, char *argv[])
 	 * tcop/postgres.c (the option sets should not conflict) and with the
 	 * common help() function in main/main.c.
 	 */
-	while ((opt = getopt(argc, argv, "A:B:bc:C:D:d:EeFf:h:ijk:lMmN:nOo:Pp:r:S:sTt:UW:-:")) != -1)
+	while ((opt = getopt(argc, argv, "A:B:bc:C:D:d:EeFf:h:ijk:lMmN:nOo:Pp:r:S:sTt:W:-:")) != -1)
 	{
 		switch (opt)
 		{
@@ -918,18 +918,6 @@ PostmasterMain(int argc, char *argv[])
 					break;
 				}
 
-			case 'U':
-				/*
-				 * In upgrade mode, we indicate we're in upgrade mode and
-				 * 1. allow DML on persistent table & catalog table
-				 * 2. alter DDL on catalog table (NOTE: upgrade_mode must set beforehand)
-				 * 3. TODO: disable the 4.1 xlog format (stick with the old)
-				 */
-				SetConfigOption("upgrade_mode",                         "true", PGC_POSTMASTER, PGC_S_ARGV);
-				SetConfigOption("allow_segment_DML",  		            "true", PGC_POSTMASTER, PGC_S_ARGV);
-				SetConfigOption("allow_system_table_mods",              "true",  PGC_POSTMASTER, PGC_S_ARGV);
-				break;
-
 			case 'W':
 				SetConfigOption("post_auth_delay", optarg, PGC_POSTMASTER, PGC_S_ARGV);
 				break;

src/backend/tcop/postgres.c

@@ -4293,7 +4293,7 @@ process_postgres_switches(int argc, char *argv[], GucContext ctx,
 	 * postmaster/postmaster.c (the option sets should not conflict) and with
 	 * the common help() function in main/main.c.
 	 */
-	while ((flag = getopt(argc, argv, "A:B:bc:C:D:d:EeFf:h:ijk:lMm:N:nOo:Pp:r:S:sTt:Uv:W:y:-:")) != -1)
+	while ((flag = getopt(argc, argv, "A:B:bc:C:D:d:EeFf:h:ijk:lMm:N:nOo:Pp:r:S:sTt:v:W:y:-:")) != -1)
 	{
 		switch (flag)
 		{
@@ -4439,18 +4439,6 @@ process_postgres_switches(int argc, char *argv[], GucContext ctx,
 					break;
 				}
 
-			case 'U':
-				/*
-				 * In upgrade mode, we indicate we're in upgrade mode and
-				 * 1. allow DML on persistent table & catalog table
-				 * 2. alter DDL on catalog table (NOTE: upgrade_mode must set beforehand)
-				 * 3. TODO: disable the 4.1 xlog format (stick with the old)
-				 */
-				SetConfigOption("upgrade_mode",                         "true", ctx, gucsource);
-				SetConfigOption("allow_segment_DML",  		            "true", ctx, gucsource);
-				SetConfigOption("allow_system_table_mods",              "true",  ctx, gucsource);
-				break;
-
 			case 'v':
 
 				/*

src/include/utils/guc.h

@@ -306,7 +306,6 @@ extern bool debug_basebackup;
 /* Latch mechanism debug GUCs */
 extern bool debug_latch;
 
-extern bool gp_upgrade_mode;
 extern bool gp_maintenance_mode;
 extern bool gp_maintenance_conn;
 extern bool allow_segment_DML;