apache/druid · error · IAE

At most one of properties

Error message

At most one of properties[%s] must be present

What it means

Checks.checkOneNotNullOrEmpty enforces that at most one property from a given set has a non-empty value. If two or more of the listed properties are set, an IAE listing all property names is thrown while parsing the Hadoop batch job/config object.

Solutions

1. Remove all but one of the conflicting properties in the ingestion spec.
2. Use only the property recommended by the current ingestion spec schema.
3. Regenerate the spec so only the intended input source field is populated.

Example fix

// before
"inputPaths": "hdfs://a/b",
"inputSpec": {"type": "static", "paths": "hdfs://a/b"}
// after
"inputSpec": {"type": "static", "paths": "hdfs://a/b"}

int present = Stream.of(prop1, prop2, prop3).filter(p -> p.getValue() != null && !isEmptyCollection(p.getValue())).count();
if (present > 1) { throw new IllegalArgumentException("At most one input property may be set"); }

try { Checks.checkOneNotNullOrEmpty(p1, p2); } catch (IAE e) { log.error("Mutually exclusive properties set: {}", e.getMessage()); throw e; }

When it happens

Trigger: Constructing or deserializing a Hadoop indexing config (e.g. HadoopIngestionSpec / GranularitySpec-style input specs) where two mutually exclusive properties (like two input path/spec options) are both provided.

Common situations: Hadoop batch ingestion specs that specify both inputPaths and a separate input spec; generated JSON templates that fill in multiple optional fields.

Related errors

• At most one of [ ] or [ ] must be present
• A local input source accepts only one of
• A local input source can set parameter
• At least one of properties
• Cannot define both uri and fileRegex

AI-assisted analysis of apache/druid@9b90983fd2 (2026-09-07). Data as JSON: /api/errors/cfc161fbff4cb8c5. Report an issue: GitHub.

Appendix: source

Thrown at processing/src/main/java/org/apache/druid/indexer/Checks.java:40

import org.apache.druid.java.util.common.IAE;

import java.util.List;
import java.util.stream.Collectors;

/**
 * Various helper methods useful for checking the validity of arguments to spec constructors.
 */
public final class Checks
{
  public static <T> Property<T> checkOneNotNullOrEmpty(List<Property<T>> properties)
  {
    Property<T> nonNullProperty = null;
    for (Property<T> property : properties) {
      if (!property.isValueNullOrEmptyCollection()) {
        if (nonNullProperty == null) {
          nonNullProperty = property;
        } else {
          throw new IAE(
              "At most one of properties[%s] must be present",
              properties.stream().map(Property::getName).collect(Collectors.toList())
          );
        }
      }
    }
    if (nonNullProperty == null) {
      throw new IAE(
          "At least one of properties[%s] must be present",
          properties.stream().map(Property::getName).collect(Collectors.toList())
      );
    }
    return nonNullProperty;
  }

  /**
   * @return Non-null value, or first one if both are null. -1 is interpreted as null for historical reasons.
   */

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