apache/druid · error

Error reading response

Error message

Error reading response

What it means

When updating a lookup node via HTTP POST, a non-success response is received. The coordinator tries to read the response body for the error message; if reading the stream itself throws IOException, it logs a warning that the error response could not be read, then still throws an IOException describing the failed update.

Source

Thrown at server/src/main/java/org/apache/druid/server/lookup/cache/LookupCoordinatorManager.java:823

                result,
                LOOKUPS_STATE_TYPE_REFERENCE
            );
            LOG.debug(
                "Update on [%s], Status: %s reason: [%s], Response [%s].", url, returnCode.get(), reasonString.get(),
                response
            );
            return response;
          }
          catch (IOException ex) {
            throw new IOE(ex, "Failed to parse update response from [%s]. response [%s]", url, result);
          }
        } else {
          final ByteArrayOutputStream baos = new ByteArrayOutputStream();
          try {
            StreamUtils.copyAndClose(result, baos);
          }
          catch (IOException e2) {
            LOG.warn(e2, "Error reading response");
          }

          throw new IOE(
              "Bad update request to [%s] : [%d] : [%s]  Response: [%s]",
              url,
              returnCode.get(),
              reasonString.get(),
              StringUtils.fromUtf8(baos.toByteArray())
          );
        }
      }
    }

    public LookupsState<LookupExtractorFactoryMapContainer> getLookupStateForNode(
        HostAndPortWithScheme node
    ) throws IOException, InterruptedException, ExecutionException
    {
      final URL url = getLookupsURL(node);

View on GitHub (pinned to 9b90983fd2)

Solutions

1. Check connectivity and health of the target lookup node URL.
2. Inspect lookup node logs for why the update returned a bad status.
3. Retry the lookup update; the management loop will retry on the next cycle.

// pre-check node health before update
int code = httpGetStatus(nodeUrl + "/status/health");
if (code != 200) throw new SkipUpdateException(nodeUrl);

try { updateNode(url, lookups); } catch (IOException e) { LOG.warn("lookup update to %s failed, will retry next cycle", url, e); }

When it happens

Trigger: updateNode() POSTs to a lookup node and receives a bad HTTP status; StreamUtils.copyAndClose fails reading the error body (connection reset, stream closed).

Common situations: Lookup node under load resets connections; node crashed mid-response; network interruption between coordinator and node; wrong port/URL hitting a different service.

Understand the failure class

Background: "API error: {status}" and "HTTP 401/403/404/429/5xx" errors: non-2xx HTTP responses explained — this error's family across 27 libraries.

Related errors

• Error reading response from GET on url [%s]
• Could not fetch last modified timestamp from URI [%s]
• Requested to skip [%s] bytes, but actual number of bytes ski
• Error occurred while trying to read uri:
• Failed to open range reader for segment[%s]

AI-assisted analysis of apache/druid@9b90983fd2 (2026-09-07). Data as JSON: /api/errors/3052615baea8c80e. Report an issue: GitHub.