apache/druid · error · ExpressionValidationException

argument must be a LONG constant

Error message

argument must be a LONG constant

What it means

The bloom_filter_expr / bloom_filter_operand macro requires its single argument (the expected filter size) to be a literal LONG constant. If the argument is not a literal or has a null literal value, expression validation fails with 'argument must be a LONG constant'.

Solutions

1. Pass a constant integer literal, e.g. bloom_filter_expr(1000).
2. Remove any dynamic (non-literal) expression from the argument.
3. Ensure the literal is a number, not a string, and not NULL.

Example fix

// before
SELECT bloom_filter_expr(col_size) FROM t
// after
SELECT bloom_filter_expr(1000) FROM t

// validate args before building the expression
if (args.size() != 1 || !args.get(0).isLiteral() || !(args.get(0).getLiteralValue() instanceof Number)) {
  throw new IllegalArgumentException("expected a LONG literal, e.g. bloom_filter_expr(1000)");
}

boolean isValidSizeArg(Expr e) { return e != null && e.isLiteral() && e.getLiteralValue() != null && e.getLiteralValue() instanceof Number; }

When it happens

Trigger: Calling BLOOM_FILTER_EXPECTED_SIZE-like macros with a non-literal expression (e.g., a column reference or computed expression) or a null literal as the size argument.

Common situations: Passing a column or query parameter instead of a constant integer; forgetting the argument defaults expectation; using a string literal instead of a number.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• Failed to deserialize bloom filter
• attempt to get boolean[] null vector from string[] only…
• attempt to get double[] from string[] only scalar binding
• attempt to get long[] from string[] only scalar binding
• bf1Length does not match bf2Length

AI-assisted analysis of apache/druid@9b90983fd2 (2026-09-07). Data as JSON: /api/errors/3690d4a4ea0d6672. Report an issue: GitHub.

Appendix: source

Thrown at extensions-core/druid-bloom-filter/src/main/java/org/apache/druid/query/expressions/BloomFilterExpressions.java:62

  public static class CreateExprMacro implements ExprMacroTable.ExprMacro
  {
    public static final String FN_NAME = "bloom_filter";

    @Override
    public String name()
    {
      return FN_NAME;
    }

    @Override
    public Expr apply(List<Expr> args)
    {
      validationHelperCheckArgumentCount(args, 1);

      final Expr expectedSizeArg = args.get(0);

      if (!expectedSizeArg.isLiteral() || expectedSizeArg.getLiteralValue() == null) {
        throw validationFailed("argument must be a LONG constant");
      }

      class BloomExpr extends ExprMacroTable.BaseScalarMacroFunctionExpr
      {
        final int expectedSize;

        public BloomExpr(List<Expr> args)
        {
          super(CreateExprMacro.this, args);
          this.expectedSize = args.get(0).eval(InputBindings.nilBindings()).asInt();
        }

        @Override
        public ExprEval eval(ObjectBinding bindings)
        {
          return ExprEval.ofComplex(
              BLOOM_FILTER_TYPE,
              new BloomKFilter(expectedSize)

View on GitHub (pinned to 9b90983fd2)