pinpoint-apm/pinpoint · error · IllegalStateException

Unexpected samplerType: ${samplerType}

Error message

Unexpected samplerType: ${samplerType}

What it means

SamplerProvider.newSamplerFactory throws IllegalStateException('Unexpected samplerType') when the parsed TraceSamplerType does not match any supported switch case (e.g. COUNTING or PERCENT). The default branch marks a parse failure of the configured sampler type string. It prevents the profiler from running with an unknown sampling strategy.

Source

Thrown at agent-module/profiler/src/main/java/com/navercorp/pinpoint/profiler/context/provider/sampler/SamplerProvider.java:67

        if (!config.isSamplingEnable()) {
            return FalseSampler.INSTANCE;
        }

        SamplerType samplerType = config.getSamplerType();
        SamplerFactory samplerFactory = newSamplerFactory(samplerType, profilerConfig);

        return samplerFactory.createSampler();
    }

    private SamplerFactory newSamplerFactory(SamplerType samplerType, ProfilerConfig profilerConfig) {
        switch (samplerType) {
            case COUNTING:
                return newCountingSamplerFactory(profilerConfig);
            case PERCENT:
                return newPercentSamplerFactory(profilerConfig);
            default:
                // parse fail
                throw new IllegalStateException("Unexpected samplerType: " + samplerType);
        }
    }

    private SamplerFactory newCountingSamplerFactory(ProfilerConfig profilerConfig) {

        CountingSamplerFactory.Config config = CountingSamplerFactory.config(profilerConfig);
        logger.info("CountingSamplerFactory.Config:{}", config);

        return new CountingSamplerFactory(config);
    }

    private SamplerFactory newPercentSamplerFactory(ProfilerConfig profilerConfig) {

        PercentSamplerFactory.Config config = PercentSamplerFactory.config(profilerConfig);
        logger.info("PercentSamplerFactory.Config:{}", config);

        return new PercentSamplerFactory(config);
    }

View on GitHub (pinned to 744c3d3075)

Solutions

1. Set profiler.sampling.type... to a supported value: PERCENT or COUNTING
2. Fix typos in the sampling configuration property value
3. Check the Pinpoint version's documentation for valid sampler type names and remove unsupported values
4. Validate the whole profiler configuration file after an upgrade

Example fix

// before
profiler.sampling.type.sampling=new
profiler.sampling.new.sampler.type=percet
// after
profiler.sampling.type.sampling=new
profiler.sampling.new.sampler.type=percent

String samplerType = config.readString("profiler.sampling.new.sampler.type");
if (!"PERCENT".equalsIgnoreCase(samplerType) && !"COUNTING".equalsIgnoreCase(samplerType)) {
    throw new IllegalArgumentException("Invalid sampler type: " + samplerType);
}

boolean isValidSamplerType(String s) {
    return "PERCENT".equalsIgnoreCase(s) || "COUNTING".equalsIgnoreCase(s);
}

try {
    Sampler sampler = samplerProvider.get();
} catch (IllegalStateException e) {
    logger.error("Sampler configuration invalid: {}", e.getMessage());
    throw e;
}

When it happens

Trigger: The profiler.sampling.type... configuration value fails to map to a known TraceSamplerType during parsing, so samplerFactory -> newSamplerFactory ends in the switch default branch.

Common situations: Typos in the sampling type property (e.g. 'percet' instead of 'percent'), an unsupported sampler type name copied from an example config, or a config file from a different Pinpoint version with a removed sampler type.

Understand the failure class

Background: "Invalid value" and "allowed values are" config errors: what your library rejected and how to fix it — this error's family across 41 libraries.

Related errors

• service type name must not be empty
• Invalid type provider definition :
• invalid full qualified method name(). not found method
• invalid oracle jdbc url:<driverUrl>
• agentInfoRefreshIntervalMs must be greater than 0

AI-assisted analysis of pinpoint-apm/pinpoint@744c3d3075 (2026-09-07). Data as JSON: /api/errors/063717ea12e80152. Report an issue: GitHub.