dgraph-io/dgraph · error

Unsupported operation in facet filtering: %s.

Error message

Unsupported operation in facet filtering: %s.

What it means

Error returned by the query processing worker (worker/task.go) when a facet filter uses an operation that is not supported for facet filtering. The unsupported operation name is reported via %s. Fix by using a supported facet filter operator.

Source

Thrown at worker/task.go:2494

		ftree.children = append(ftree.children, ftreec)
	}

	numChild := len(tree.Children)
	switch ftree.op {
	case "not":
		if numChild != 1 {
			return nil, errors.Errorf("Expected 1 child for not but got %d.", numChild)
		}
	case "and":
		if numChild != 2 {
			return nil, errors.Errorf("Expected 2 child for not but got %d.", numChild)
		}
	case "or":
		if numChild != 2 {
			return nil, errors.Errorf("Expected 2 child for not but got %d.", numChild)
		}
	default:
		return nil, errors.Errorf("Unsupported operation in facet filtering: %s.", tree.Op)
	}
	return ftree, nil
}

type countParams struct {
	readTs  uint64
	counts  []int64
	attr    string
	gid     uint32
	reverse bool   // If query is asking for ~pred
	fn      string // function name
}

func (qs *queryState) evaluate(cp countParams, out *pb.Result) error {
	countl := cp.counts[0]
	var counth int64
	if cp.fn == between {
		counth = cp.counts[1]

View on GitHub (pinned to 759e242be6)

Solutions

1. Rewrite the facet filter using only not/and/or plus supported facet comparison functions.
2. If using a client library to build queries, verify it supports facets correctly for your Dgraph version.
3. Simplify the query to isolate which construct produces the unsupported operator.

Example fix

// before
friend @facets(has(score))
// after
friend filter has(friend) { @facets(gt(score, 3)) }

const allowedOps = new Set(["not","and","or"]);
function validateFacetOps(tree) {
  if (!allowedOps.has(tree.op)) throw new Error(`Unsupported facet op: ${tree.op}`);
  (tree.children || []).forEach(validateFacetOps);
}

try {
  return await txn.query(query);
} catch (e) {
  if (/Unsupported operation in facet filtering/.test(String(e))) {
    // strip/relocate the unsupported construct and retry
  }
  throw e;
}

When it happens

Trigger: An internal filter tree node whose Op is neither not, and, nor or reaches the facet preprocessing — typically from a query construct unsupported in @facets or from programming errors building query trees programmatically.

Common situations: Using math/has/uid functions in facet position; client libraries emitting custom operator names; corrupted or hand-constructed query ASTs.

Related errors

• Cannot specify order at both args and facets
• One argument expected in %s, but got %d.
• Fn %s not supported in preprocessFilter.
• Expected 1 child for not but got %d.
• Expected 2 child for not but got %d.

AI-assisted analysis of dgraph-io/dgraph@759e242be6 (2026-09-01). Data as JSON: /api/errors/053b5f265612b62c. Report an issue: GitHub.