apache/seatunnel · error · ElasticsearchConnectorException

GET_INDEX_DOCS_COUNT_FAILED

GET_INDEX_DOCS_COUNT_FAILED

Error message

GET {endpoint} response null

What it means

Thrown when the GET /_cat/indices/{index}?h=index,docsCount&format=json request used to fetch the document count of an index returns a null Response from the Elasticsearch REST client. The library raises GET_INDEX_DOCS_COUNT_FAILED because it cannot read the count without a response. In practice a null response is rare and usually indicates a client/proxy anomaly.

Source

Thrown at seatunnel-connectors-v2/connector-elasticsearch/src/main/java/org/apache/seatunnel/connectors/seatunnel/elasticsearch/client/EsRestClient.java:559

        try {
            Response response = restClient.performRequest(request);
            int statusCode = response.getStatusLine().getStatusCode();
            return statusCode == 200;
        } catch (Exception ex) {
            throw new ElasticsearchConnectorException(
                    ElasticsearchConnectorErrorCode.CHECK_INDEX_FAILED, ex);
        }
    }

    public List<IndexDocsCount> getIndexDocsCount(String index) {
        String endpoint =
                String.format(
                        "/_cat/indices/%s?h=index,docsCount&format=json", index.toLowerCase());
        Request request = new Request("GET", endpoint);
        try {
            Response response = restClient.performRequest(request);
            if (response == null) {
                throw new ElasticsearchConnectorException(
                        ElasticsearchConnectorErrorCode.GET_INDEX_DOCS_COUNT_FAILED,
                        "GET " + endpoint + " response null");
            }
            String entity = EntityUtils.toString(response.getEntity(), StandardCharsets.UTF_8);
            if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
                return JsonUtils.toList(entity, IndexDocsCount.class);
            } else {
                throw new ElasticsearchConnectorException(
                        ElasticsearchConnectorErrorCode.GET_INDEX_DOCS_COUNT_FAILED,
                        String.format(
                                "GET %s response status code=%d, body=%s",
                                endpoint, response.getStatusLine().getStatusCode(), entity));
            }
        } catch (IOException ex) {
            throw new ElasticsearchConnectorException(
                    ElasticsearchConnectorErrorCode.GET_INDEX_DOCS_COUNT_FAILED, ex);
        }
    }

View on GitHub (pinned to cf67b549a7)

Solutions

1. Check that the RestClient is built by the standard ES Low Level REST Client, not a wrapper that can return null
2. Log/inspect the client configuration (httpHosts, auth, proxy) for anomalies
3. Enable client tracing to see whether a request was actually sent and what came back
4. If null persists, upgrade/align the elasticsearch-rest-client version used by the connector

boolean hasResponse(Response r) { return r != null; }

try {
    long count = client.getIndexDocsCountSize(indexName);
} catch (ElasticsearchConnectorException e) {
    if (e.getMessage().startsWith("GET ") && e.getMessage().contains("response null")) {
        // fall back to a direct search with track_total_hits
        // or abort with a clear diagnostic about the client setup
    }
    throw e;
}

When it happens

Trigger: getIndexDocsCount / getIndexDocsCountSize path where restClient.performRequest returns null instead of a Response object.

Common situations: Custom or wrapped RestClient implementations that swallow responses; interceptors/proxies returning null on internal errors; unusual client versions where performRequest contract differs.

Understand the failure class

Background: 'Something went wrong' / 'Request failed (500)' / 'HTTP error! status: 404' — what failed HTTP requests actually mean and how to find the real cause — this error's family across 28 libraries.

Related errors

• LIST_INDEX_FAILED
• CREATE_INDEX_FAILED
• DROP_INDEX_FAILED
• CLEAR_INDEX_DATA_FAILED
• ADD_FIELD_FAILED

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/a3b1b1e3b82f6bc4. Report an issue: GitHub.