Fix pg_upgrade to preserve toast relfrozenxids for old 8.3 servers.

This fixes a pg_upgrade bug that could lead to query errors when
clog files are improperly removed.

Backpatch to 8.4, 9.0, 9.1.

Author: bmomjian

src/bin/pg_dump/pg_dump.c

@@ -3978,14 +3978,13 @@ getTables(int *numTables)
 		 * owning column, if any (note this dependency is AUTO as of 8.2)
 		 */
 		appendPQExpBuffer(query,
-						  "SELECT c.tableoid, c.oid, relname, "
-						  "relacl, relkind, relnamespace, "
-						  "(%s relowner) AS rolname, "
-						  "relchecks, (reltriggers <> 0) AS relhastriggers, "
-						  "relhasindex, relhasrules, relhasoids, "
-						  "relfrozenxid, "
-						  "0 AS toid, "
-						  "0 AS tfrozenxid, "
+						  "SELECT c.tableoid, c.oid, c.relname, "
+						  "c.relacl, c.relkind, c.relnamespace, "
+						  "(%s c.relowner) AS rolname, "
+						  "c.relchecks, (c.reltriggers <> 0) AS relhastriggers, "
+						  "c.relhasindex, c.relhasrules, c.relhasoids, "
+						  "c.relfrozenxid, tc.oid AS toid, "
+						  "tc.relfrozenxid AS tfrozenxid, "
 						  "'p' AS relpersistence, "
 						  "NULL AS reloftype, "
 						  "d.refobjid AS owning_tab, "
@@ -3999,7 +3998,8 @@ getTables(int *numTables)
 						  "d.classid = c.tableoid AND d.objid = c.oid AND "
 						  "d.objsubid = 0 AND "
 						  "d.refclassid = c.tableoid AND d.deptype = 'a') "
-						  "WHERE relkind in ('%c', '%c', '%c', '%c') "
+					   "LEFT JOIN pg_class tc ON (c.reltoastrelid = tc.oid) "
+						  "WHERE c.relkind in ('%c', '%c', '%c', '%c') "
 						  "ORDER BY c.oid",
 						  username_subquery,
 						  RELKIND_SEQUENCE,