alibaba/arthas · error · IllegalArgumentException

sizeLimit must be greater than 0.

Error message

sizeLimit must be greater than 0.

What it means

Thrown by checkArguments() in the `tt` (time tunnel) command when the --sizeLimit option is non-null and <= 0. validateSizeLimit() returns this message and checkArguments() wraps it in IllegalArgumentException. sizeLimit controls how many time fragments the tunnel can record, so it must be a positive integer.

Source

Thrown at core/src/main/java/com/taobao/arthas/core/command/monitor200/TimeTunnelCommand.java:250

    private boolean hasSearchExpress() {
        return !StringUtils.isEmpty(searchExpress);
    }

    static String validateSizeLimit(Integer sizeLimit) {
        if (sizeLimit != null && sizeLimit.intValue() <= 0) {
            return "sizeLimit must be greater than 0.";
        }
        return null;
    }

    /**
     * 检查参数是否合法
     */
    private void checkArguments() {
        String validateError = validateSizeLimit(sizeLimit);
        if (validateError != null) {
            throw new IllegalArgumentException(validateError);
        }

        // 检查d/p参数是否有i参数配套
        if ((isDelete || isPlay) && null == index) {
            throw new IllegalArgumentException("Time fragment index is expected, please type -i to specify");
        }

        // 在t参数下class-pattern,method-pattern
        if (isTimeTunnel) {
            if (StringUtils.isEmpty(classPattern)) {
                throw new IllegalArgumentException("Class-pattern is expected, please type the wildcard expression to match");
            }
            if (StringUtils.isEmpty(methodPattern)) {
                throw new IllegalArgumentException("Method-pattern is expected, please type the wildcard expression to match");
            }
        }

        // 一个参数都没有是不行滴

View on GitHub (pinned to 21cf2e9ba5)

Solutions

1. Set --sizeLimit to a positive integer (e.g. the default), or omit it to use the default.
2. If you want a large buffer, pass a large positive value rather than 0.

Example fix

// before
tt -t --class-pattern demo.MathGame --method-pattern prime --sizeLimit 0
// after
tt -t --class-pattern demo.MathGame --method-pattern prime --sizeLimit 1000

static String checkSizeLimit(Integer sizeLimit) {
    return (sizeLimit != null && sizeLimit <= 0)
        ? "sizeLimit must be > 0" : null;
}

null

null

When it happens

Trigger: Running `tt --sizeLimit 0` or `tt --sizeLimit -1` (e.g. `tt -t --class-pattern X --method-pattern Y --sizeLimit 0`).

Common situations: Passing 0 intending 'unlimited' (Arthas uses a positive integer, not 0, for limits); misconfigured scripting defaulting sizeLimit to 0; sign error.

Related errors

• Too many line numbers, maximum is 256.
• Time fragment index is expected, please type -i to specify
• Invalid line number: {}
• Line number must be greater than 0: {}
• Class-pattern is expected, please type the wildcard expressi

AI-assisted analysis of alibaba/arthas@21cf2e9ba5 (2026-08-14). Data as JSON: /api/errors/c14fb632f81f9bb0. Report an issue: GitHub.