apache/beam · error · UnsupportedOperationException

the function in Measures is not recognized.

Error message

the function in Measures is not recognized.

What it means

CEPUtils.getFieldType() resolves the SQL type of a MEASURES expression by locating a field reference (RexPatternFieldRef) among a RexCall's operands. If the call's operands contain no recognizable field ref, it throws UnsupportedOperationException, meaning the MEASURES function's output type cannot be inferred.

Source

Thrown at sdks/java/extensions/sql/src/main/java/org/apache/beam/sdk/extensions/sql/impl/cep/CEPUtils.java:210

      return streamSchema.getField(field.getIndex()).getType();
    } else if (measureOperation.getClass() == CEPCall.class) {

      CEPCall call = (CEPCall) measureOperation;
      CEPKind oprKind = call.getOperator().getCepKind();

      if (oprKind == CEPKind.SUM || oprKind == CEPKind.COUNT) {
        return Schema.FieldType.INT32;
      } else if (oprKind == CEPKind.AVG) {
        return Schema.FieldType.DOUBLE;
      }
      CEPFieldRef refOpt;
      for (CEPOperation i : call.getOperands()) {
        refOpt = getFieldRef(i);
        if (refOpt != null) {
          return streamSchema.getField(refOpt.getIndex()).getType();
        }
      }
      throw new UnsupportedOperationException("the function in Measures is not recognized.");
    } else {
      throw new UnsupportedOperationException("the function in Measures is not recognized.");
    }
  }
}

View on GitHub (pinned to 12126d8942)

Solutions

1. Reference at least one pattern variable field in each MEASURES expression (e.g. A.price instead of a constant).
2. Cast or wrap the constant so it is tied to a field, or compute it outside MATCH_RECOGNIZE.
3. If legitimate, extend CEPUtils.getFieldType() to fall back to the RexCall's own inferred type via the type factory.
4. Catch UnsupportedOperationException at query-translation time and report the unsupported MEASURES expression to the user.

Example fix

// before
MEASURES 1 + 1 AS two
// after
MEASURES A.quantity + 1 AS qtyPlusOne

// Ensure each MEASURES expr references at least one pattern field
if (!referencesPatternField(measuresRexNode)) {
  throw new IllegalArgumentException("MEASURES expression must reference a pattern field");
}

boolean referencesPatternField(RexNode n) { return getFieldRef(n) != null; } // reuse CEPUtils.getFieldRef

try { return CEPUtils.getFieldType(call, schema); } catch (UnsupportedOperationException e) { throw new QueryValidationException("Unresolvable MEASURES expression", e); }

When it happens

Trigger: A MEASURES clause expression (RexCall) whose operands include no RexPatternFieldRef reachable via getFieldRef() — e.g. constant-only expressions or functions over literals.

Common situations: MEASURES with expressions like 1+1, constant aggregates, or functions applied only to literals in a MATCH_RECOGNIZE query; Calcite rewrites stripping field refs.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

• RexNode not supported: ${className}
• The other object should be an instance of CEPLiteral
• The other CEPLiteral should have type , given:
• the comparator is not supported: ${comparator}
• the function is not supported for now: ${cepKind}

AI-assisted analysis of apache/beam@12126d8942 (2026-09-13). Data as JSON: /api/errors/5877096f188c58da. Report an issue: GitHub.