Merge pull request #42733 from pbardea/backport19.2-42005

release-19.2: backupccl: allow restoration of empty db

pkg/ccl/backupccl/backup_test.go

@@ -1579,15 +1579,14 @@ func TestBackupRestoreCrossTableReferences(t *testing.T) {
 
 		// Test cases where, after filtering out views that can't be restored, there are no other tables to restore
 
-		db.ExpectErr(t, `no tables to restore: DATABASE storestats`,
-			`RESTORE DATABASE storestats from $1 WITH OPTIONS ('skip_missing_views')`, localFoo)
+		db.Exec(t, `RESTORE DATABASE storestats from $1 WITH OPTIONS ('skip_missing_views')`, localFoo)
+		db.Exec(t, `RESTORE storestats.ordercounts from $1 WITH OPTIONS ('skip_missing_views')`, localFoo)
+		// Ensure that the views were not restored since they are missing the tables they reference.
+		db.CheckQueryResults(t, `USE storestats; SHOW TABLES;`, [][]string{})
 
-		db.ExpectErr(t, `no tables to restore: TABLE storestats.ordercounts`,
-			`RESTORE storestats.ordercounts from $1 WITH OPTIONS ('skip_missing_views')`, localFoo)
-
-		// referencing_early_customers depends only on early_customers, which can't be restored
-		db.ExpectErr(t, `no tables to restore: TABLE store.early_customers, store.referencing_early_customers`,
-			`RESTORE store.early_customers, store.referencing_early_customers from $1 WITH OPTIONS ('skip_missing_views')`, localFoo)
+		db.Exec(t, `RESTORE store.early_customers, store.referencing_early_customers from $1 WITH OPTIONS ('skip_missing_views')`, localFoo)
+		// Ensure that the views were not restored since they are missing the tables they reference.
+		db.CheckQueryResults(t, `SHOW TABLES;`, [][]string{})
 
 		// Test that views with valid dependencies are restored
 
@@ -3084,6 +3083,21 @@ func TestBackupCreatedStats(t *testing.T) {
 		})
 }
 
+// Ensure that backing up and restoring an empty database succeeds.
+func TestBackupRestoreEmptyDB(t *testing.T) {
+	defer leaktest.AfterTest(t)()
+
+	const numAccounts = 1
+	_, _, sqlDB, _, cleanupFn := backupRestoreTestSetup(t, singleNode, numAccounts, initNone)
+	defer cleanupFn()
+
+	sqlDB.Exec(t, `CREATE DATABASE empty`)
+	sqlDB.Exec(t, `BACKUP DATABASE empty TO $1`, localFoo)
+	sqlDB.Exec(t, `DROP DATABASE empty`)
+	sqlDB.Exec(t, `RESTORE DATABASE empty FROM $1`, localFoo)
+	sqlDB.CheckQueryResults(t, `USE empty; SHOW TABLES;`, [][]string{})
+}
+
 func TestBackupRestoreSubsetCreatedStats(t *testing.T) {
 	defer leaktest.AfterTest(t)()
 

pkg/ccl/backupccl/restore.go

@@ -214,15 +214,8 @@ func selectTargets(
 		return nil, nil, err
 	}
 
-	seenTable := false
-	for _, desc := range matched.descs {
-		if desc.Table(hlc.Timestamp{}) != nil {
-			seenTable = true
-			break
-		}
-	}
-	if !seenTable {
-		return nil, nil, errors.Errorf("no tables found: %s", tree.ErrString(&targets))
+	if len(matched.descs) == 0 {
+		return nil, nil, errors.Errorf("no tables or databases matched the given targets: %s", tree.ErrString(&targets))
 	}
 
 	if lastBackupDesc.FormatVersion >= BackupFormatDescriptorTrackingVersion {
@@ -1546,9 +1539,6 @@ func doRestorePlan(
 	if err != nil {
 		return err
 	}
-	if len(filteredTablesByID) == 0 {
-		return errors.Errorf("no tables to restore: %s", tree.ErrString(&restoreStmt.Targets))
-	}
 	tableRewrites, err := allocateTableRewrites(ctx, p, databasesByID, filteredTablesByID, restoreDBs, opts)
 	if err != nil {
 		return err
@@ -1761,6 +1751,17 @@ func (r *restoreResumer) Resume(
 	}
 	r.tables = tables
 	r.databases = databases
+	r.exec = p.ExecCfg().InternalExecutor
+	r.statsRefresher = p.ExecCfg().StatsRefresher
+	r.latestStats = remapRelevantStatistics(latestBackupDesc, details.TableRewrites)
+
+	if len(r.tables) == 0 {
+		// We have no tables to restore (we are restoring an empty DB).
+		// Since we have already created any new databases that we needed,
+		// we can return without importing any data.
+		log.Warning(ctx, "no tables to restore")
+		return nil
+	}
 
 	res, err := restore(
 		ctx,
@@ -1776,9 +1777,6 @@ func (r *restoreResumer) Resume(
 		r.job,
 	)
 	r.res = res
-	r.exec = p.ExecCfg().InternalExecutor
-	r.statsRefresher = p.ExecCfg().StatsRefresher
-	r.latestStats = remapRelevantStatistics(latestBackupDesc, details.TableRewrites)
 	return err
 }