--- title: Rejected requests description: When Elasticsearch rejects a request, it stops the operation and returns an HTTP 429 response code for a TOO_MANY_REQUESTS error. The returned HTTP response... url: https://www.elastic.co/elastic/docs-builder/docs/3028/troubleshoot/elasticsearch/rejected-requests products: - Elasticsearch applies_to: - Elastic Cloud Serverless: Generally available - Elastic Stack: Generally available --- # Rejected requests When Elasticsearch rejects a request, it stops the operation and returns an HTTP `429` response code for a `TOO_MANY_REQUESTS` error. The returned HTTP response body includes information on why the operation was rejected. You can retry HTTP `429` errors, but it's generally best to implement [exponential backoff](https://en.wikipedia.org/wiki/Exponential_backoff) to avoid exacerbating performance issues. ## Check rejected tasks Rejected requests are frequently caused by depleted resources. The most common of these are described here. ### Review thread pools To check the number of rejected tasks for each thread pool, use the [cat thread pool API](https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-cat-thread-pool): ```json ``` A high ratio of `rejected` to `completed` tasks, particularly in the `search` and `write` thread pools, indicates that Elasticsearch regularly rejects requests. The following examples demonstrate typical `queue capacity` errors. - The API response body returns an `es_rejected_execution_exception` error: ```json { "shard" : 0, "node" : "XXXX", "reason" : { "reason" : "rejected execution of org.elasticsearch.common.util.concurrent.TimedRunnable@26c03d4a on QueueResizingEsThreadPoolExecutor[name = XXXXX/search, queue capacity = 1000, min queue capacity = 1000, max queue capacity = 1000, frame size = 2000, targeted response rate = 1s, task execution EWMA = 968.1ms, adjustment amount = 50, org.elasticsearch.common.util.concurrent.QueueResizingEsThreadPoolExecutor@70be0765[Running, pool size = 25, active threads = 25, queued tasks = 1000, completed tasks = 616499351]]", "type" : "es_rejected_execution_exception" }, "index" : "my-index-000001" } ``` - The error log returns an `EsRejectedExecutionException` error: ``` Caused by: org.elasticsearch.common.util.concurrent.EsRejectedExecutionException: rejected execution of org.elasticsearch.common.util.concurrent.TimedRunnable@1a25fe82 on QueueResizingEsThreadPoolExecutor[name = XXXXX/search, queue capacity = 1000, min queue capacity = 1000, max queue capacity = 1000, frame size = 2000, targeted response rate = 1s, task execution EWMA = 10.7ms, adjustment amount = 50, org.elasticsearch.common.util.concurrent.QueueResizingEsThreadPoolExecutor@6312a0bb[Running, pool size = 25, active threads = 25, queued tasks = 1000, completed tasks = 616499351]] ``` To troubleshoot ongoing thread pool rejection errors, check [task queue backlog due to thread pool](/elastic/docs-builder/docs/3028/troubleshoot/elasticsearch/task-queue-backlog#diagnose-task-queue-thread-pool). Refer to the [Threadpool Rejections video](https://www.youtube.com/watch?v=auZJRXoAVpI) for a troubleshooting walkthrough. ## Inspect circuit breakers To check the number of tripped [circuit breakers](https://docs-v3-preview.elastic.dev/elastic/docs-builder/docs/3028/reference/elasticsearch/configuration-reference/circuit-breaker-settings), use the [node stats API](https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-nodes-stats). ```json ``` These statistics are cumulative from node startup. For more information, see [circuit breaker errors](https://www.elastic.co/elastic/docs-builder/docs/3028/troubleshoot/elasticsearch/circuit-breaker-errors). Refer to the [Circuit Breaker Error video](https://www.youtube.com/watch?v=k3wYlRVbMSw) for a troubleshooting walkthrough. ## Analyze indexing pressure Elasticsearch reserves part of its JVM for indexing. An error can occur if heap usage exceeds the [`indexing_pressure.memory.limit` setting](https://docs-v3-preview.elastic.dev/elastic/docs-builder/docs/3028/reference/elasticsearch/index-settings/pressure#memory-limits). To check the number of [indexing pressure](https://docs-v3-preview.elastic.dev/elastic/docs-builder/docs/3028/reference/elasticsearch/index-settings/pressure) rejections, use the [node stats API](https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-nodes-stats). ```json ``` These statistics are cumulative from node startup. The following examples demonstrate indexing pressure rejections. - The API response body returns an `es_rejected_execution_exception` error: ```json { "error" : { "root_cause" : [ { "type" : "es_rejected_execution_exception", "reason" : "rejected execution of primary operation [coordinating_and_primary_bytes=XXXXX, replica_bytes=XXXXX, all_bytes=XXXXX, coordinating_operation_bytes=XXXXX, max_coordinating_and_primary_bytes=XXXXX]" } ], "type" : "es_rejected_execution_exception", "reason" : "rejected execution of coordinating operation [coordinating_and_primary_bytes=XXXXX, replica_bytes=XXXXX, all_bytes=XXXXX, coordinating_operation_bytes=XXXXX, max_coordinating_and_primary_bytes=XXXXX]" }, "status" : 429 } ``` - The error log returns an `EsRejectedExecutionException` error: ``` Caused by: org.elasticsearch.common.util.concurrent.EsRejectedExecutionException: rejected execution of primary operation [coordinating_and_primary_bytes=XXXXX, replica_bytes=XXXXX, all_bytes=XXXXX, coordinating_operation_bytes=XXXXX, max_coordinating_and_primary_bytes=XXXXX] ``` As part of the [Reading and writing documents](https://www.elastic.co/elastic/docs-builder/docs/3028/deploy-manage/distributed-architecture/reading-and-writing-documents) outlined models, the portion of the error `rejected execution of operation` reports one of the following categories: `combined_coordinating_and_primary`, `coordinating`, `primary`, or `replica`. These errors are often related to: - The quantity of [backlogged tasks](https://www.elastic.co/elastic/docs-builder/docs/3028/troubleshoot/elasticsearch/task-queue-backlog). - The value of [Bulk index](https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-bulk) is set to too large of a size. - Large search response sizes. - Use of the [`semantic_text`](https://docs-v3-preview.elastic.dev/elastic/docs-builder/docs/3028/reference/elasticsearch/mapping-reference/semantic-text) field type, which can cause rejections when indexing large batches of documents if the batch may otherwise incur an Out of Memory (OOM) error. Elastic Stack: Generally available since 9.1Elastic Cloud Serverless: Generally available Refer to the [Index Pressure Rejections video](https://www.youtube.com/watch?v=QuV8QqSfc0c) for a troubleshooting walkthrough. ## Prevent rejected requests AutoOps is a [monitoring](https://www.elastic.co/elastic/docs-builder/docs/3028/deploy-manage/monitor) tool that simplifies cluster management through performance recommendations, resource utilization visibility, and real-time issue detection with resolution paths. Learn more about [AutoOps](https://www.elastic.co/elastic/docs-builder/docs/3028/deploy-manage/monitor/autoops). ### Fix high CPU and memory usage If Elasticsearch regularly rejects requests and other tasks, your cluster likely has high CPU usage or high JVM memory pressure. For tips, refer to [High CPU usage](https://www.elastic.co/elastic/docs-builder/docs/3028/troubleshoot/elasticsearch/high-cpu-usage) and [High JVM memory pressure](https://www.elastic.co/elastic/docs-builder/docs/3028/troubleshoot/elasticsearch/high-jvm-memory-pressure). ### Fix for `semantic_text` ingestion issues - Elastic Cloud Serverless: Generally available - Elastic Stack: Generally available since 9.1 When bulk indexing documents with the [`semantic_text`](https://docs-v3-preview.elastic.dev/elastic/docs-builder/docs/3028/reference/elasticsearch/mapping-reference/semantic-text) field type, you might encounter rejections due to high memory usage during inference processing. These rejections appear as an `InferenceException` in your cluster logs. To resolve this issue: 1. Reduce the batch size of documents in your indexing requests. 2. If reducing batch size doesn't resolve the issue, then consider scaling up your machine resources. 3. Elastic Cloud Serverless: Unavailable A last resort option is to adjust the `indexing_pressure.memory.coordinating.limit` cluster setting. The default value is 10% of the heap. Increasing this limit allows more memory to be used for coordinating operations before rejections occur. This adjustment should only be considered after exhausting other options, as setting this value too high may risk Out of Memory (OOM) errors in your cluster. A cluster restart is required for this change to take effect.