What causes "invalid int value for %v: %v" in vitessio/vitess?

Resubmit the value as a plain base-10 integer, e.g. 10000 instead of 10k

invalid int value for %v: %v

Error message

invalid int value for %v: %v

What it means

The tabletserver debug env endpoint (/debug/env, ADMIN-only) allows live-tuning variables via POST. For integer variables set through setIntVal (MaxResultSize, WarnResultSize), the submitted value must parse with strconv.Atoi; this error is returned — surfaced as HTTP 400 — when the value is not a valid integer.

Source

Thrown at go/vt/vttablet/tabletserver/debugenv.go:97

	default:
		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
	}
}

func handlePost(tsv *TabletServer, w http.ResponseWriter, r *http.Request) {
	varname := r.FormValue("varname")
	value := r.FormValue("value")

	var msg string
	if varname == "" || value == "" {
		http.Error(w, "Missing varname or value", http.StatusBadRequest)
		return
	}

	setIntVal := func(f func(int)) error {
		ival, err := strconv.Atoi(value)
		if err != nil {
			return fmt.Errorf("invalid int value for %v: %v", varname, err)
		}
		f(ival)
		msg = fmt.Sprintf("Setting %v to: %v", varname, value)
		return nil
	}

	setIntValCtx := func(f func(context.Context, int) error) error {
		ival, err := strconv.Atoi(value)
		if err == nil {
			err = f(r.Context(), ival)
		}
		if err != nil {
			return fmt.Errorf("failed setting value for %v: %v", varname, err)
		}
		msg = fmt.Sprintf("Setting %v to: %v", varname, value)
		return nil
	}

View on GitHub (pinned to 01a25a7d17)

Solutions

Resubmit the value as a plain base-10 integer, e.g. 10000 instead of 10k
Remove any whitespace, commas, or units from the value
Check the wrapped strconv error in the message for the exact parse problem (syntax vs out-of-range)
Use the /debug/env page's form directly so the varname/value form fields are populated correctly

Example fix

// before: POST value
value="10k"
// after
value="10000"

Defensive patterns

Strategy: validation

Validate before calling

value := "10000"
if _, err := strconv.Atoi(value); err != nil {
    return fmt.Errorf("%s is not a plain base-10 integer", value)
}
// then POST /debug/env?varname=MaxResultSize&value=10000

Try / catch

resp, err := http.PostForm(url, url.Values{"varname": {"MaxResultSize"}, "value": {"10000"}})
if resp.StatusCode == http.StatusBadRequest {
    body, _ := io.ReadAll(resp.Body)
    log.Warn("debug env rejected value", slog.String("body", string(body)))
}

Prevention

Always submit plain base-10 integers — no units (10k), commas, spaces, or signs other than leading '-'
Verify values with strconv.Atoi locally before scripting the POST
Use the /debug/env HTML form so varname/value fields are populated correctly
Remember int overflow also fails — keep values within Go int range

When it happens

Trigger: POST /debug/env with varname=MaxResultSize or WarnResultSize and a value that fails strconv.Atoi — e.g. '10k', '1,000', ' 100' (leading space), an empty/whitespace string, or an out-of-int-range number.

Common situations: Operators pasting values with units ('10000k') or thousands separators into the debug env HTML form; curl scripts sending unquoted or locale-formatted numbers.

Related errors

AI-assisted analysis of vitessio/vitess@01a25a7d17 (2026-09-01). Data as JSON: /api/errors/ba6a7fe158f747e2. Report an issue: GitHub.