apache/druid · error · UnsupportedOperationException

Required column rewrite is not supported by this filter.

Error message

Required column rewrite is not supported by this filter.

What it means

Filter.rewriteRequiredColumns is a default no-op throwing UnsupportedOperationException; only filters that support column rewriting override it. Thrown when a caller attempts to rewrite a filter type (or filter tree containing a type) that does not implement rewriting.

Source

Thrown at processing/src/main/java/org/apache/druid/query/filter/Filter.java:183

  default boolean supportsRequiredColumnRewrite()
  {
    return false;
  }

  /**
   * Return a copy of this filter that is identical to the this filter except that it operates on different columns,
   * based on a renaming map where the key is the column to be renamed in the filter, and the value is the new
   * column name.
   * <p>
   * For example, if I have a filter (A = hello), and I have a renaming map (A -> B),
   * this should return the filter (B = hello)
   *
   * @param columnRewrites Column rewrite map
   * @return Copy of this filter that operates on new columns based on the rewrite map
   */
  default Filter rewriteRequiredColumns(Map<String, String> columnRewrites)
  {
    throw new UnsupportedOperationException("Required column rewrite is not supported by this filter.");
  }
}

View on GitHub (pinned to 9b90983fd2)

Solutions

Upgrade or implement rewriteRequiredColumns for the filter type.
Skip rewriting filters that do not support it (catch the exception and keep the original filter).
Use a supported filter equivalent (e.g. selector/in/and/or) that implements column rewriting.

Example fix

// before
Filter rewritten = filter.rewriteRequiredColumns(rewrites);
// after
Filter rewritten;
try {
  rewritten = filter.rewriteRequiredColumns(rewrites);
} catch (UnsupportedOperationException e) {
  rewritten = filter; // keep original when rewrite unsupported
}

Defensive patterns

Strategy: try-catch

Try / catch

try { rewritten = filter.rewriteRequiredColumns(rewrites); } catch (UnsupportedOperationException e) { rewritten = filter; }

Prevention

Prefer filter types that implement rewriteRequiredColumns (selector, in, and, or, not)
Guard unnest-rewrite passes with capability checks
Keep custom filters in sync with Filter interface defaults

When it happens

Trigger: Calling rewriteFilterRequiredColumns / rewriteFilterOnUnnestColumnIfPossible on a filter class that does not override rewriteRequiredColumns (e.g. custom filters or unsupported built-ins).

Common situations: SQL-to-native unnest rewrites encountering a filter type added before rewrite support existed; third-party filter extensions.

Related errors

AI-assisted analysis of apache/druid@9b90983fd2 (2026-09-07). Data as JSON: /api/errors/23fbd92be055d34c. Report an issue: GitHub.