[cli] estimate-gc with custom TTL

Release note:
`cockroach debug estimate-gc` now allows user to specify TTL period,
with a default of 24 hours.

pkg/cli/debug.go

@@ -90,13 +90,21 @@ Create a ballast file to fill the store directory up to a given amount
// It must do nothing in OSS code.
var PopulateRocksDBConfigHook func(*engine.RocksDBConfig) error

func parseRangeID(arg string) (roachpb.RangeID, error) {
	rangeIDInt, err := strconv.ParseInt(arg, 10, 64)
func parsePositiveInt(arg string) (int64, error) {
	i, err := strconv.ParseInt(arg, 10, 64)
	if err != nil {
		return 0, err
	}
	if rangeIDInt < 1 {
		return 0, fmt.Errorf("illegal RangeID: %d", rangeIDInt)
	if i < 1 {
		return 0, fmt.Errorf("illegal val: %d < 1", i)
	}
	return i, nil
}

func parseRangeID(arg string) (roachpb.RangeID, error) {
	rangeIDInt, err := parsePositiveInt(arg)
	if err != nil {
		return 0, err
	}
	return roachpb.RangeID(rangeIDInt), nil
}
@@ -448,7 +456,7 @@ func runDebugRaftLog(cmd *cobra.Command, args []string) error {
}

var debugGCCmd = &cobra.Command{
	Use:   "estimate-gc <directory> [range id]",
	Use:   "estimate-gc <directory> [range id] [ttl-in-seconds]",
	Short: "find out what a GC run would do",
	Long: `
Sets up (but does not run) a GC collection cycle, giving insight into how much
@@ -457,7 +465,7 @@ work would be done (assuming all intent resolution and pushes succeed).
Without a RangeID specified on the command line, runs the analysis for all
ranges individually.

Uses a hard-coded GC policy with a 24 hour TTL for old versions.
Uses a configurable GC policy, with a default 24 hour TTL, for old versions.
`,
	Args: cobra.RangeArgs(1, 2),
	RunE: MaybeDecorateGRPCError(runDebugGCCmd),
@@ -468,7 +476,18 @@ func runDebugGCCmd(cmd *cobra.Command, args []string) error {
	defer stopper.Stop(context.Background())

	var rangeID roachpb.RangeID
	if len(args) == 2 {
	gcTTLInSeconds := int64((24 * time.Hour).Seconds())
	switch len(args) {
	case 3:
		var err error
		if rangeID, err = parseRangeID(args[1]); err != nil {
			return errors.Wrapf(err, "unable to parse %v as range ID", args[1])
		}
		if gcTTLInSeconds, err = parsePositiveInt(args[2]); err != nil {
			return errors.Wrapf(err, "unable to parse %v as TTL", args[2])
		}

	case 2:
		var err error
		if rangeID, err = parseRangeID(args[1]); err != nil {
			return err
@@ -519,7 +538,7 @@ func runDebugGCCmd(cmd *cobra.Command, args []string) error {
			&desc,
			snap,
			hlc.Timestamp{WallTime: timeutil.Now().UnixNano()},
			config.GCPolicy{TTLSeconds: 24 * 60 * 60 /* 1 day */},
			config.GCPolicy{TTLSeconds: int32(gcTTLInSeconds)},
			storage.NoopGCer{},
			func(_ context.Context, _ []roachpb.Intent) error { return nil },
			func(_ context.Context, _ *roachpb.Transaction, _ []roachpb.Intent) error { return nil },