apache/druid · error · IllegalArgumentException

Cannot create query type helper from invalid type

Error message

Cannot create query type helper from invalid type [%s]

What it means

SearchQueryRunner's makeColumnSelectorStrategy switch handles only STRING, LONG, FLOAT, and DOUBLE column capabilities; any other type (e.g. COMPLEX) reaches the default branch and throws IAE('Cannot create query type helper from invalid type [%s]'). It means a search was attempted on a column whose data type the search machinery cannot scan directly. Searching complex columns (e.g. nested/sketch columns) triggers it.

Solutions

1. Restrict the search query's dimensions to string/long/float/double columns
2. Use a virtual column or expression (e.g. JSON path expressions) to search inside complex columns
3. Fix ingestion specs so the target column has a supported type, or re-ingest with the right type

Example fix

// before
{"queryType":"search","dimensions":["complexMetricColumn"]}
// after
{"queryType":"search","dimensions":["stringDimension"]} // or a nested virtual column

ColumnCapabilities caps = selector.getColumnCapabilities(dim); if (caps == null || !EnumSet.of(STRING, LONG, FLOAT, DOUBLE).contains(caps.getType())) { throw new IllegalArgumentException("unsupported search column: " + dim); }

boolean isSearchableType(ColumnCapabilities c) { return c != null && (c.getType() == ValueType.STRING || c.getType() == ValueType.LONG || c.getType() == ValueType.FLOAT || c.getType() == ValueType.DOUBLE); }

try { runner.run(queryPlus, ctx); } catch (IAE e) { if (e.getMessage().contains("invalid type")) { rewriteQueryWithSupportedColumns(); } else throw e; }

When it happens

Trigger: Issuing a search query with dimensions referencing a COMPLEX or otherwise unsupported column type; schema changes leaving a column type unsupported by search strategies.

Common situations: Searching nested or metric (complex aggregator) columns; auto-detection assigning unexpected types during ingestion; typos hitting a complex column instead of a string dimension.

Related errors

• Unknown type[ ]
• Aggregation [ ] does not support column [ ] of type [ ]…
• Can only handle [ ], got [ ]
• Cannot create query type helper from invalid type
• Cannot handle column

AI-assisted analysis of apache/druid@9b90983fd2 (2026-09-07). Data as JSON: /api/errors/53fb9a631f78ab07. Report an issue: GitHub.

Appendix: source

Thrown at processing/src/main/java/org/apache/druid/query/search/SearchQueryRunner.java:85

  {
    @Override
    public SearchColumnSelectorStrategy makeColumnSelectorStrategy(
        ColumnCapabilities capabilities,
        ColumnValueSelector selector,
        String dimension
    )
    {
      switch (capabilities.getType()) {
        case STRING:
          return new StringSearchColumnSelectorStrategy();
        case LONG:
          return new LongSearchColumnSelectorStrategy();
        case FLOAT:
          return new FloatSearchColumnSelectorStrategy();
        case DOUBLE:
          return new DoubleSearchColumnSelectorStrategy();
        default:
          throw new IAE("Cannot create query type helper from invalid type [%s]", capabilities.asTypeString());
      }
    }

    @Override
    public boolean supportsComplexTypes()
    {
      return false;
    }
  }

  public interface SearchColumnSelectorStrategy<ValueSelectorType> extends ColumnSelectorStrategy
  {
    /**
     * Read the current row from dimSelector and update the search result set.
     * <p>
     * For each row value:
     * 1. Check if searchQuerySpec accept()s the value
     * 2. If so, add the value to the result set and increment the counter for that value

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