What causes "ERROR: unable to parse cache percentage(%s)" in dgraph-io/dgraph?

Ensure every comma-separated value is a plain non-negative integer (e.g. "50,50")

ERROR: unable to parse cache percentage(%s)

Error message

ERROR: unable to parse cache percentage(%s)

What it means

Each comma-separated element of the cache percentage string must parse as an integer via strconv.Atoi. When an element is not a valid integer, GetCachePercentages returns this error naming the offending element.

Source

Thrown at x/x.go:1397

	return aCopy
}

// GetCachePercentages returns the slice of cache percentages given the "," (comma) separated
// cache percentages(integers) string and expected number of caches.
func GetCachePercentages(cpString string, numExpected int) ([]int64, error) {
	cp := strings.Split(cpString, ",")
	// Sanity checks
	if len(cp) != numExpected {
		return nil, errors.Errorf("ERROR: expected %d cache percentages, got %d",
			numExpected, len(cp))
	}

	var cachePercent []int64
	percentSum := 0
	for _, percent := range cp {
		x, err := strconv.Atoi(percent)
		if err != nil {
			return nil, errors.Errorf("ERROR: unable to parse cache percentage(%s)", percent)
		}
		if x < 0 {
			return nil, errors.Errorf("ERROR: cache percentage(%s) cannot be negative", percent)
		}
		cachePercent = append(cachePercent, int64(x))
		percentSum += x
	}

	if percentSum != 100 {
		return nil, errors.Errorf("ERROR: cache percentages (%s) does not sum up to 100",
			strings.Join(cp, "+"))
	}

	return cachePercent, nil
}

// ParseCompression returns badger.compressionType and compression level given compression string
// of format compression-type:compression-level

View on GitHub (pinned to 759e242be6)

Solutions

Ensure every comma-separated value is a plain non-negative integer (e.g. "50,50")
Remove units, spaces, or decimals from the cache percentage config
Validate the string by splitting on ',' and strconv.Atoi-ing each item before calling

Example fix

// before
cp, err := GetCachePercentages("50 %,50", 2) // unparsable "50 %"
// after
cp, err := GetCachePercentages("50,50", 2)

Defensive patterns

Strategy: validation

Validate before calling

func validCachePctString(cpString string) bool {
    for _, p := range strings.Split(cpString, ",") {
        if _, err := strconv.Atoi(strings.TrimSpace(p)); err != nil { return false }
    }
    return true
}

Type guard

func isParsablePercent(s string) bool { _, err := strconv.Atoi(strings.TrimSpace(s)); return err == nil }

Prevention

Store cache percentages as plain integers without '%' or spaces
Trim whitespace on each CSV element before parsing
Use typed config (list of ints) instead of raw strings where possible

When it happens

Trigger: Calling GetCachePercentages with a string containing a non-numeric item, e.g. "50,abc" or values with units/spaces like "50 %,50".

Common situations: Typo'd config values, pasting percentages with '%' or spaces, decimal values like '33.3' (not integers), or locale-formatted numbers.

Understand the failure class

Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

AI-assisted analysis of dgraph-io/dgraph@759e242be6 (2026-09-01). Data as JSON: /api/errors/14212eb2803346b6. Report an issue: GitHub.