Add RestorePosition and RestoredBackupTime as metrics to vttablet (#1…

…3339)

* Add BackupPosition and BackupTime as metrics to vttablet

Signed-off-by: Rohit Nayak <rohit@planetscale.com>

* add to release notes

Signed-off-by: deepthi <deepthi@planetscale.com>

---------

Signed-off-by: Rohit Nayak <rohit@planetscale.com>
Signed-off-by: deepthi <deepthi@planetscale.com>
Co-authored-by: deepthi <deepthi@planetscale.com>

changelog/16.0/16.0.0/release_notes.md

@@ -5,6 +5,7 @@
 
 - **[Known Issues](#known-issues)**
   - [MySQL & Xtrabackup known issue](#mysql-xtrabackup-ddl)
+  - [VTTablet Restore Metrics](#vttablet-restore-metrics)
 - **[Major Changes](#major-changes)**
   - **[Breaking Changes](#breaking-changes)**
     - [VTGate Advertised MySQL Version](#advertised-mysql-version)
@@ -100,6 +101,11 @@ or
 > ALTER TABLE your_table ENGINE=InnoDB;
 ```
 
+#### <a id="vttablet-restore-metrics">VTTablet Restore Metrics
+
+As part of the VTTablet Sidecar Schema Maintenance Refactor in v16.0.0, we dropped the `local_metadata` table from the sidecar database schema. This table was storing a couple of metrics related to restores from backup, which have now been lost.
+They have been re-introduced in v17.0.0 as metrics that can be accessed from `/debug/vars`.
+
 ## <a id="major-changes"/>Major Changes
 
 ### <a id="breaking-changes"/>Breaking Changes

changelog/17.0/17.0.0/release_notes.md

@@ -12,6 +12,7 @@
     - [Shard name validation in TopoServer](#shard-name-validation)
     - [Compression CLI flags removed from vtctld and vtctldclient binaries](#remove-compression-flags-from-vtctld-binaries)
     - [VtctldClient command RestoreFromBackup will now use the correct context](#VtctldClient-RestoreFromBackup)
+    - [VTTablet Restore Metrics](#vttablet-restore-metrics)
   - **[New command line flags and behavior](#new-flag)**
     - [Builtin backup: read buffering flags](#builtin-backup-read-buffering-flags)
     - [Manifest backup external decompressor command](#manifest-backup-external-decompressor-command)
@@ -132,6 +133,11 @@ Prior to v17, this asynchronous process could run indefinitely in the background
 this behavior was changed to use a context with a timeout of `action_timeout`. If you are using VtctldClient to initiate a restore, make sure you provide an appropriate value for action_timeout to give enough
 time for the restore process to complete. Otherwise, the restore will throw an error if the context expires before it completes.
 
+#### <a id="vttablet-restore-metrics">VTTablet Restore Metrics
+
+As part of the VTTablet Sidecar Schema Maintenance Refactor in v16.0.0, we dropped the `local_metadata` table from the sidecar database schema. This table was storing a couple of metrics related to restores from backup.
+They have now been re-introduced as metrics that can be accessed from `/debug/vars`.
+
 ### <a id="Vttablet-TxThrottler">Vttablet's transaction throttler now also throttles DML outside of `BEGIN; ...; COMMIT;` blocks
 
 Prior to v17, `vttablet`'s transaction throttler (enabled with `--enable-tx-throttler`) would only throttle requests done inside an explicit transaction, i.e., a `BEGIN; ...; COMMIT;` block.

go/test/endtoend/backup/vtctlbackup/backup_utils.go

@@ -1233,11 +1233,27 @@ func verifyTabletBackupStats(t *testing.T, vars map[string]any) {
 	if backupstorage.BackupStorageImplementation == "file" {
 		require.Contains(t, bd, "BackupStorage.File.File:Write")
 	}
+
+}
+
+func verifyRestorePositionAndTimeStats(t *testing.T, vars map[string]any) {
+	backupPosition := vars["RestorePosition"].(string)
+	backupTime := vars["RestoredBackupTime"].(string)
+	require.Contains(t, vars, "RestoredBackupTime")
+	require.Contains(t, vars, "RestorePosition")
+	require.NotEqual(t, "", backupPosition)
+	require.NotEqual(t, "", backupTime)
+	rp, err := mysql.DecodePosition(backupPosition)
+	require.NoError(t, err)
+	require.False(t, rp.IsZero())
 }
 
 func verifyTabletRestoreStats(t *testing.T, vars map[string]any) {
 	// Currently only the builtin backup engine instruments bytes-processed
 	// counts.
+
+	verifyRestorePositionAndTimeStats(t, vars)
+
 	if !useXtrabackup {
 		require.Contains(t, vars, "RestoreBytes")
 		bb := vars["RestoreBytes"].(map[string]any)

go/vt/vttablet/tabletmanager/restore.go

@@ -24,6 +24,8 @@ import (
 
 	"github.com/spf13/pflag"
 
+	"vitess.io/vitess/go/stats"
+
 	"vitess.io/vitess/go/mysql"
 	"vitess.io/vitess/go/vt/dbconfigs"
 	"vitess.io/vitess/go/vt/hook"
@@ -53,6 +55,9 @@ var (
 	restoreFromBackupTsStr string
 	restoreConcurrency     = 4
 	waitForBackupInterval  time.Duration
+
+	statsRestoreBackupTime     *stats.String
+	statsRestoreBackupPosition *stats.String
 )
 
 func registerRestoreFlags(fs *pflag.FlagSet) {
@@ -93,6 +98,9 @@ func init() {
 
 	servenv.OnParseFor("vtcombo", registerPointInTimeRestoreFlags)
 	servenv.OnParseFor("vttablet", registerPointInTimeRestoreFlags)
+
+	statsRestoreBackupTime = stats.NewString("RestoredBackupTime")
+	statsRestoreBackupPosition = stats.NewString("RestorePosition")
 }
 
 // RestoreData is the main entry point for backup restore.
@@ -222,6 +230,10 @@ func (tm *TabletManager) restoreDataLocked(ctx context.Context, logger logutil.L
 	var backupManifest *mysqlctl.BackupManifest
 	for {
 		backupManifest, err = mysqlctl.Restore(ctx, params)
+		if backupManifest != nil {
+			statsRestoreBackupPosition.Set(mysql.EncodePosition(backupManifest.Position))
+			statsRestoreBackupTime.Set(backupManifest.BackupTime)
+		}
 		params.Logger.Infof("Restore: got a restore manifest: %v, err=%v, waitForBackupInterval=%v", backupManifest, err, waitForBackupInterval)
 		if waitForBackupInterval == 0 {
 			break