apache/cassandra · error · ConfigurationException

%s must be greater than zero

Error message

%s must be greater than zero

What it means

After successfully parsing the 'size' option as an integer, fromMap() validates it is at least 1. A size of zero or negative is rejected with a ConfigurationException, since a fast-path coordinator quorum must contain at least one replica.

Source

Thrown at src/java/org/apache/cassandra/service/accord/topology/ParameterizedFastPathStrategy.java:257

    }

    public static ParameterizedFastPathStrategy fromMap(Map<String, String> map)
    {
        if (!map.containsKey(SIZE))
            throw cfe("fast_path must be set to 'keyspace' or 'default' or a map defining '%s' and optionally '%s'", SIZE, DCS);

        int size;
        try
        {
            size = Integer.parseInt(map.get(SIZE));
        }
        catch (NumberFormatException e)
        {
            throw cfe("%s must be a positive number, got %s", SIZE, map.get(SIZE));
        }

        if (size < 1)
            throw cfe("%s must be greater than zero", SIZE);

        ImmutableMap<String, WeightedDc> dcMap;
        if (map.containsKey(DCS) && !map.get(DCS).isEmpty())
        {
            Map<String, WeightedDc> mutableDcs = new HashMap<>();
            String dcsString = map.get(DCS);
            if (dcsString.trim().isEmpty())
                throw cfe("%s must specify at least one DC", DCS);

            int autoIdx = 0;
            boolean hasAuto = false;
            boolean hasManual = false;
            for (String dcString : COMMA_SEPARATOR.split(dcsString))
            {
                WeightedDc dc = WeightedDc.fromString(dcString, autoIdx++);
                if (mutableDcs.containsKey(dc.name))
                    throw cfe("Multiple entries for DC %s", dc.name);

View on GitHub (pinned to 88fd0f6a0e)

Solutions

1. Set 'size' to a positive integer (>= 1)
2. If the fast path should be disabled, remove the 'size' key entirely rather than setting 0
3. Clamp generated/config-managed values to >= 1 before passing to fromMap()

Example fix

// before
Map<String,String> opts = Map.of("size", "0");
ParameterizedFastPathStrategy.fromMap(opts); // throws
// after
Map<String,String> opts = Map.of("size", "1");
ParameterizedFastPathStrategy.fromMap(opts); // ok

int size = Integer.parseInt(map.get("size"));
if (size < 1)
    throw new IllegalArgumentException("size must be >= 1, got: " + size);

When it happens

Trigger: Calling fromMap() with {"size": "0"} or {"size": "-5"} — any integer less than 1.

Common situations: Disabling the fast path by setting size to 0 instead of omitting/unsetting the option; hand-editing configuration with a negative value.

Understand the failure class

Background: "value must be between 0 and 1" / "out of range" / "must not be negative" errors: fixing range-validation failures across open-source libraries — this error's family across 42 libraries.

Related errors

• Invalid accord progress log configuration:
• Concurrent accord operations must be non-negative
• DC weights must be zero or positive
• %s must be a positive number, got %s
• %s must specify at least one DC

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/c055caa3da15229b. Report an issue: GitHub.