Back up foreign data wrapper objects on Cloudberry

backup/predata_acl.go

@@ -488,14 +488,20 @@ func (obj ObjectMetadata) GetOwnerStatement(objectName string, objectType string
 }
 
 func (obj ObjectMetadata) GetCommentStatement(objectName string, objectType string, owningTable string) string {
+	typeStr := objectType
+	// COMMENT uses "SERVER", not "FOREIGN SERVER" (mirrors GetOwnerStatement).
+	// Emitting "COMMENT ON FOREIGN SERVER ..." is a syntax error on restore.
+	if objectType == toc.OBJ_FOREIGN_SERVER {
+		typeStr = toc.OBJ_SERVER
+	}
 	commentStr := ""
 	tableStr := ""
 	if owningTable != "" {
 		tableStr = fmt.Sprintf(" ON %s", owningTable)
 	}
 	if obj.Comment != "" {
 		escapedComment := utils.EscapeSingleQuotes(obj.Comment)
-		commentStr = fmt.Sprintf("COMMENT ON %s %s%s IS '%s';", objectType, objectName, tableStr, escapedComment)
+		commentStr = fmt.Sprintf("COMMENT ON %s %s%s IS '%s';", typeStr, objectName, tableStr, escapedComment)
 	}
 	return commentStr
 }

backup/wrappers.go

@@ -418,7 +418,14 @@ func retrieveCasts(sortables *[]Sortable, metadataMap MetadataMap) {
 }
 
 func retrieveFDWObjects(sortables *[]Sortable, metadataMap MetadataMap) {
-	if !(connectionPool.Version.IsGPDB() && connectionPool.Version.AtLeast("6")) || connectionPool.Version.IsCBDB() {
+	// Foreign data wrappers, servers and user mappings exist on GPDB 6+ and on
+	// Cloudberry. The condition must skip only when the server is neither, i.e.
+	// negate the whole "GPDB 6+ OR Cloudberry" predicate. A misplaced negation
+	// here previously skipped these objects on Cloudberry, so their CREATE
+	// SERVER / FOREIGN DATA WRAPPER / USER MAPPING statements were omitted from
+	// the backup and any foreign table that depended on them failed to restore
+	// with "server ... does not exist".
+	if !((connectionPool.Version.IsGPDB() && connectionPool.Version.AtLeast("6")) || connectionPool.Version.IsCBDB()) {
 		return
 	}
 	retrieveForeignDataWrappers(sortables, metadataMap)

end_to_end/end_to_end_suite_test.go

@@ -850,6 +850,49 @@ var _ = Describe("backup and restore end to end tests", func() {
 			Expect(tocStruct.GlobalEntries[0].ObjectType).To(Equal(toc.OBJ_SESSION_GUC))
 		})
 	})
+	Describe("foreign data wrapper objects tests", func() {
+		It("backs up and restores foreign data wrappers, servers, user mappings and foreign tables", func() {
+			// Regression test for a bug where retrieveFDWObjects skipped FDW
+			// objects on Cloudberry: the foreign table was backed up but its
+			// server was not, so the restore failed with "server does not exist".
+			if !((backupConn.Version.IsGPDB() && backupConn.Version.AtLeast("6")) || backupConn.Version.IsCBDB()) {
+				Skip("Foreign data wrappers require GPDB 6+ or Cloudberry")
+			}
+			testhelper.AssertQueryRuns(backupConn, "CREATE FOREIGN DATA WRAPPER fdw;")
+			defer testhelper.AssertQueryRuns(backupConn, "DROP FOREIGN DATA WRAPPER fdw CASCADE;")
+			testhelper.AssertQueryRuns(backupConn, "CREATE SERVER fdw_server FOREIGN DATA WRAPPER fdw;")
+			// A server comment must be emitted as "COMMENT ON SERVER", not
+			// "COMMENT ON FOREIGN SERVER", or the restore aborts with a syntax error.
+			testhelper.AssertQueryRuns(backupConn, "COMMENT ON SERVER fdw_server IS 'fdw server comment';")
+			testhelper.AssertQueryRuns(backupConn, "CREATE USER MAPPING FOR CURRENT_USER SERVER fdw_server;")
+			testhelper.AssertQueryRuns(backupConn, "CREATE FOREIGN TABLE public.fdw_table (i int) SERVER fdw_server;")
+
+			output := gpbackup(gpbackupPath, backupHelperPath, "--backup-dir", backupDir, "--metadata-only")
+			timestamp := getBackupTimestamp(string(output))
+
+			gprestore(gprestorePath, restoreHelperPath, timestamp,
+				"--backup-dir", backupDir,
+				"--redirect-db", "restoredb",
+				"--metadata-only")
+			defer testhelper.AssertQueryRuns(restoreConn, "DROP FOREIGN DATA WRAPPER fdw CASCADE;")
+
+			// Without the fix the server (and its dependents) would be missing.
+			serverCount := dbconn.MustSelectString(restoreConn,
+				"SELECT count(*) FROM pg_foreign_server WHERE srvname = 'fdw_server'")
+			Expect(serverCount).To(Equal("1"))
+			mappingCount := dbconn.MustSelectString(restoreConn,
+				"SELECT count(*) FROM pg_user_mappings WHERE srvname = 'fdw_server'")
+			Expect(mappingCount).To(Equal("1"))
+			foreignTableCount := dbconn.MustSelectString(restoreConn,
+				"SELECT count(*) FROM pg_class WHERE relname = 'fdw_table' AND relkind = 'f'")
+			Expect(foreignTableCount).To(Equal("1"))
+			// The server comment must survive restore; a "COMMENT ON FOREIGN
+			// SERVER" statement would have aborted the restore instead.
+			serverComment := dbconn.MustSelectString(restoreConn,
+				"SELECT coalesce(obj_description(oid, 'pg_foreign_server'), '') FROM pg_foreign_server WHERE srvname = 'fdw_server'")
+			Expect(serverComment).To(Equal("fdw server comment"))
+		})
+	})
 	Describe(`On Error Continue`, func() {
 		It(`gprestore continues when encountering errors during data load with --single-data-file and --on-error-continue`, func() {
 			if segmentCount != 3 {