alibaba/Sentinel · error · IllegalStateException

batchAdd() is unavailable if countAndSum() has been called

Error message

batchAdd() is unavailable if countAndSum() has been called

What it means

StatEntryFuncCountAndSum only supports count() and countAndSum(); batchAdd(long... values), which adds multiple values into pre-allocated array slots in one call, is incompatible with its two-scalar (count, sum) state and therefore throws IllegalStateException.

Source

Thrown at sentinel-core/src/main/java/com/alibaba/csp/sentinel/eagleeye/StatEntryFunc.java:109

    @Override
    public void arrayAdd(long... values) {
        throw new IllegalStateException("arrayAdd() is unavailable if countAndSum() has been called");
    }

    @Override
    public void arraySet(long... values) {
        throw new IllegalStateException("arraySet() is unavailable if countAndSum() has been called");
    }

    @Override
    public void minMax(long candidate, String ref) {
        throw new IllegalStateException("minMax() is unavailable if countAndSum() has been called");
    }

    @Override
    public void batchAdd(long... values) {
        throw new IllegalStateException("batchAdd() is unavailable if countAndSum() has been called");
    }

    @Override
    public void strArray(String... values) {
        throw new IllegalStateException("strArray() is unavailable if countAndSum() has been called");
    }
}

class StatEntryFuncMinMax implements StatEntryFunc {

    private AtomicReference<ValueRef> max = new AtomicReference<ValueRef>(new ValueRef(Long.MIN_VALUE, null));
    private AtomicReference<ValueRef> min = new AtomicReference<ValueRef>(new ValueRef(Long.MAX_VALUE, null));

    @Override
    public void appendTo(StringBuilder appender, char delimiter) {
        ValueRef lmax = max.get();
        ValueRef lmin = min.get();

View on GitHub (pinned to a3f40ba8e9)

Solutions

Flush batched values by looping countAndSum(1, v) over the batch instead of batchAdd.
Or recreate the entry with an array-type func that supports batchAdd.
Validate the metric-type/method pairing at startup with a smoke test that writes one record.

Example fix

// before
func.batchAdd(values); // count-and-sum entry -> throws

// after
for (long v : values) { func.countAndSum(1, v); }

Defensive patterns

Strategy: type-guard

Validate before calling

switch (func.getStatType()) {
    case 2: for (long v : values) func.countAndSum(1, v); break;
    default: func.batchAdd(values);
}

Type guard

boolean isCountAndSum(StatEntryFunc f) { return f.getStatType() == 2; }

Prevention

Batch flushers should query the strategy before choosing the flush method.
Prefer per-value writes (countAndSum loop) for count/sum metrics; batching gains little there.
Test the flush path with each metric type in CI.

When it happens

Trigger: Invoking batchAdd(values) on an entry whose func was created for count-and-sum — commonly a batching layer that groups several measurements and flushes them with batchAdd, pointed at a countAndSum entry by mistake.

Common situations: A batch-flushing recorder is reused across metric types. Metric type changed in config from array/batch to count_and_sum without updating the flusher. Copy-paste of a batch example into a counter metric.

Related errors

AI-assisted analysis of alibaba/Sentinel@a3f40ba8e9 (2026-08-14). Data as JSON: /api/errors/e7e4c241fe3a61a4. Report an issue: GitHub.