Fix pg_upgrade for oid removal.

pg_upgrade previously copied pg_largeobject_metadata over from the old
cluster. That doesn't work, because the table has oids before
578b2297. I missed that.

As most pieces of metadata for large objects already were dumped as
DDL (except for comments overwritten by pg_upgrade, due to the copy of
pg_largeobject_metadata) it seems reasonable to just also dump grants
for large objects.  If we ever consider this a relevant performance
problem, we'd need to fix the rest of the already emitted DDL
too.

There's still an open discussion about whether we'll want to force a
specific ordering for the dumped objects, as currently
pg_largeobjects_metadata potentially has a different ordering
before/after pg_upgrade, which can make automated testing a bit
harder.

Reported-By: Andrew Dunstan
Author: Andres Freund
Discussion: https://postgr.es/m/91a8a980-41bc-412b-fba2-2ba71a141c2b@2ndQuadrant.com

src/bin/pg_dump/pg_dump.c

@@ -2866,8 +2866,8 @@ dumpDatabase(Archive *fout)
 					 NULL, NULL);
 
 	/*
-	 * pg_largeobject and pg_largeobject_metadata come from the old system
-	 * intact, so set their relfrozenxids and relminmxids.
+	 * pg_largeobject comes from the old system intact, so set its
+	 * relfrozenxids and relminmxids.
 	 */
 	if (dopt->binary_upgrade)
 	{
@@ -2912,47 +2912,6 @@ dumpDatabase(Archive *fout)
 
 		PQclear(lo_res);
 
-		/*
-		 * pg_largeobject_metadata
-		 */
-		if (fout->remoteVersion >= 90000)
-		{
-			resetPQExpBuffer(loFrozenQry);
-			resetPQExpBuffer(loOutQry);
-
-			if (fout->remoteVersion >= 90300)
-				appendPQExpBuffer(loFrozenQry, "SELECT relfrozenxid, relminmxid\n"
-								  "FROM pg_catalog.pg_class\n"
-								  "WHERE oid = %u;\n",
-								  LargeObjectMetadataRelationId);
-			else
-				appendPQExpBuffer(loFrozenQry, "SELECT relfrozenxid, 0 AS relminmxid\n"
-								  "FROM pg_catalog.pg_class\n"
-								  "WHERE oid = %u;\n",
-								  LargeObjectMetadataRelationId);
-
-			lo_res = ExecuteSqlQueryForSingleRow(fout, loFrozenQry->data);
-
-			i_relfrozenxid = PQfnumber(lo_res, "relfrozenxid");
-			i_relminmxid = PQfnumber(lo_res, "relminmxid");
-
-			appendPQExpBufferStr(loOutQry, "\n-- For binary upgrade, set pg_largeobject_metadata relfrozenxid and relminmxid\n");
-			appendPQExpBuffer(loOutQry, "UPDATE pg_catalog.pg_class\n"
-							  "SET relfrozenxid = '%u', relminmxid = '%u'\n"
-							  "WHERE oid = %u;\n",
-							  atooid(PQgetvalue(lo_res, 0, i_relfrozenxid)),
-							  atooid(PQgetvalue(lo_res, 0, i_relminmxid)),
-							  LargeObjectMetadataRelationId);
-			ArchiveEntry(fout, nilCatalogId, createDumpId(),
-						 "pg_largeobject_metadata", NULL, NULL, "",
-						 "pg_largeobject_metadata", SECTION_PRE_DATA,
-						 loOutQry->data, "", NULL,
-						 NULL, 0,
-						 NULL, NULL);
-
-			PQclear(lo_res);
-		}
-
 		destroyPQExpBuffer(loFrozenQry);
 		destroyPQExpBuffer(loOutQry);
 	}
@@ -3266,18 +3225,14 @@ getBlobs(Archive *fout)
 			binfo[i].dobj.dump &= ~DUMP_COMPONENT_ACL;
 
 		/*
-		 * In binary-upgrade mode for blobs, we do *not* dump out the data or
-		 * the ACLs, should any exist.  The data and ACL (if any) will be
-		 * copied by pg_upgrade, which simply copies the pg_largeobject and
-		 * pg_largeobject_metadata tables.
-		 *
-		 * We *do* dump out the definition of the blob because we need that to
-		 * make the restoration of the comments, and anything else, work since
-		 * pg_upgrade copies the files behind pg_largeobject and
-		 * pg_largeobject_metadata after the dump is restored.
+		 * In binary-upgrade mode for blobs, we do *not* dump out the blob
+		 * data, as it will be copied by pg_upgrade, which simply copies the
+		 * pg_largeobject table. We *do* however dump out anything but the
+		 * data, as pg_upgrade copies just pg_largeobject, but not
+		 * pg_largeobject_metadata, after the dump is restored.
 		 */
 		if (dopt->binary_upgrade)
-			binfo[i].dobj.dump &= ~(DUMP_COMPONENT_DATA | DUMP_COMPONENT_ACL);
+			binfo[i].dobj.dump &= ~DUMP_COMPONENT_DATA;
 	}
 
 	/*

src/bin/pg_dump/t/002_pg_dump.pl

@@ -2791,9 +2791,9 @@ my %tests = (
 			data_only              => 1,
 			section_pre_data       => 1,
 			test_schema_plus_blobs => 1,
+			binary_upgrade => 1,
 		},
 		unlike => {
-			binary_upgrade => 1,
 			no_blobs       => 1,
 			no_privs       => 1,
 			schema_only    => 1,

src/bin/pg_upgrade/info.c

@@ -441,8 +441,7 @@ get_rel_infos(ClusterInfo *cluster, DbInfo *dbinfo)
 	 *
 	 * pg_largeobject contains user data that does not appear in pg_dump
 	 * output, so we have to copy that system table.  It's easiest to do that
-	 * by treating it as a user table.  Likewise for pg_largeobject_metadata,
-	 * if it exists.
+	 * by treating it as a user table.
 	 */
 	snprintf(query + strlen(query), sizeof(query) - strlen(query),
 			 "WITH regular_heap (reloid, indtable, toastheap) AS ( "
@@ -458,10 +457,8 @@ get_rel_infos(ClusterInfo *cluster, DbInfo *dbinfo)
 			 "                        'binary_upgrade', 'pg_toast') AND "
 			 "      c.oid >= %u::pg_catalog.oid) OR "
 			 "     (n.nspname = 'pg_catalog' AND "
-			 "      relname IN ('pg_largeobject'%s) ))), ",
-			 FirstNormalObjectId,
-			 (GET_MAJOR_VERSION(old_cluster.major_version) >= 900) ?
-			 ", 'pg_largeobject_metadata'" : "");
+			 "      relname IN ('pg_largeobject') ))), ",
+			 FirstNormalObjectId);
 
 	/*
 	 * Add a CTE that collects OIDs of toast tables belonging to the tables

src/bin/pg_upgrade/pg_upgrade.c

@@ -28,8 +28,9 @@
  *	We control all assignments of pg_enum.oid because these oids are stored
  *	in user tables as enum values.
  *
- *	We control all assignments of pg_authid.oid because these oids are stored
- *	in pg_largeobject_metadata.
+ *	We control all assignments of pg_authid.oid for historical reasons (the
+ *	oids used to be stored in pg_largeobject_metadata, which is now copied via
+ *	SQL commands), that might change at some point in the future.
  */