What causes "Query params are not supported" in apache/iceberg?

Use the delete overload without queryParams, encoding needed values into the path

apache/iceberg · error · UnsupportedOperationException

Query params are not supported

Error message

Query params are not supported

What it means

The RESTClient default delete(path, queryParams, ...) convenience overload does not support query parameters; it throws UnsupportedOperationException if any are passed and delegates to the plain delete. Callers needing query parameters must use an overload/client that supports them.

Solutions

Use the delete overload without queryParams, encoding needed values into the path
Use a concrete RESTClient implementation (e.g. HttpClient) that supports deletes with query params, if available
Drop query parameters if the endpoint does not require them
Encode filters into path segments where the REST spec defines them

Example fix

// before
client.delete("v1/namespaces/ns/tables", ImmutableMap.of("purge", "true"), respType, headers, handler);
// after
client.delete("v1/namespaces/ns/tables/purge", respType, headers, handler);

Defensive patterns

Strategy: validation

Validate before calling

if (queryParams != null && !queryParams.isEmpty()) {
  throw new IllegalArgumentException("Use delete without queryParams or a header-capable client");
}

Try / catch

try {
  return client.delete(path, queryParams, type, headers, handler);
} catch (UnsupportedOperationException e) {
  return client.delete(path, type, headers, handler); // fallback
}

Prevention

Encode filters into the request path per the REST spec, not query params
Check overload signatures before porting HTTP calls
Prefer the minimal delete overload unless you need params
Document which RESTClient overloads your concrete client supports

When it happens

Trigger: Calling restClient.delete(path, queryParams, responseType, headers, errorHandler) with a non-empty/non-null queryParams map; porting GET-style code (with filters encoded as query params) to DELETE without adjusting the call.

Common situations: Migrating code from other HTTP clients to RESTClient; trying to add filters or pagination params to a DELETE call; using the convenience overload out of habit.

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

AI-assisted analysis of apache/iceberg@86d9c8fc54 (2026-09-12). Data as JSON: /api/errors/d0f06a4d4b2e9ffb. Report an issue: GitHub.

Appendix: source

Thrown at core/src/main/java/org/apache/iceberg/rest/RESTClient.java:69

      Supplier<Map<String, String>> headers,
      Consumer<ErrorResponse> errorHandler) {
    return delete(path, ImmutableMap.of(), responseType, headers.get(), errorHandler);
  }

  <T extends RESTResponse> T delete(
      String path,
      Class<T> responseType,
      Map<String, String> headers,
      Consumer<ErrorResponse> errorHandler);

  default <T extends RESTResponse> T delete(
      String path,
      Map<String, String> queryParams,
      Class<T> responseType,
      Map<String, String> headers,
      Consumer<ErrorResponse> errorHandler) {
    if (null != queryParams && !queryParams.isEmpty()) {
      throw new UnsupportedOperationException("Query params are not supported");
    }

    return delete(path, responseType, headers, errorHandler);
  }

  default <T extends RESTResponse> T get(
      String path,
      Class<T> responseType,
      Supplier<Map<String, String>> headers,
      Consumer<ErrorResponse> errorHandler) {
    return get(path, ImmutableMap.of(), responseType, headers, errorHandler);
  }

  default <T extends RESTResponse> T get(
      String path,
      Class<T> responseType,
      Map<String, String> headers,
      Consumer<ErrorResponse> errorHandler) {

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