Write queue size
The write thread pool queue on one or more nodes is backing up with pending indexing work. When the queue stays elevated, the node cannot keep pace with ingest and might reject writes or slow co-located searches.
For a complete list of insights, refer to AutoOps insights.
| Field | Value |
|---|---|
| Component | Elasticsearch |
| Severity | Medium |
| Scope | Node |
| Domains | performance, indexing |
You can customize these settings to adjust when AutoOps detects this event and presents the insight. Refer to AutoOps event settings for details.
The default customization settings are:
| Setting | Type | Default |
|---|---|---|
| Write queue threshold | Integer | 1 |
| Consecutive samples above threshold | Integer | 1 |
Raising these thresholds reduces noise but delays detection. Lowering them triggers the insight sooner but can increase alerts during minor blips.
The following is an example of what you might see when this insight is triggered. Real insights use live data and links from your deployment or cluster.
The write thread pool queue is elevated on es-data-01 and es-data-02.
- Indices with high indexing activity:
logs-prod-000045
AutoOps shows different recommendations depending on how their conditions match your deployment or cluster.
Rollover indices
Condition: Shown when high-indexing activity is detected and if index has less primary shards than available data nodes.
If logs-prod-000045 are time-based, roll them over and set 1 primary shards on the new write index so you can avoid a heavy segment merge on the current indices.
Rollover indices by shard size
Condition: Shown when high-indexing activity is detected and if primary shard size > 30GB.
If logs-prod-000045 are time-based, roll them over when average shard size reaches your target.
Review index templates and mappings
Condition: Shown when high-indexing activity is detected and for indexes with highest indexing latency.
Review templates and mappings for logs-prod-000045; they strongly affect indexing performance. Fix oversized mappings, unnecessary fields, and inefficient index settings.
Review indexing slow logs
Condition: Shown when high indexing activity is detected on the node.
Enable indexing slow logs with the action below on logs-prod-000045, then review the logs to find slow index operations. On Elasticsearch 8.14+, set index.indexing.slowlog.include.user to true to record which user triggered a slow operation.
PUT logs-prod-000045/_settings
{
"index.indexing.slowlog.threshold.index.warn": "10s",
"index.indexing.slowlog.threshold.index.info": "5s",
"index.indexing.slowlog.threshold.index.debug": "2s",
"index.indexing.slowlog.threshold.index.trace": "500ms",
"index.indexing.slowlog.source": "1000"
}
Requires the manage index privilege. Requires Elasticsearch 8.0.0 or later. This action changes cluster or index configuration.
Add data node
Condition: Shown when high-indexing activity is detected and if index has more primary shards as available data nodes.
Add a data node to increase capacity and reduce pressure on the existing nodes.
Review indexing slow logs
Condition: Always shown for this insight.
Check indexing slow logs on es-data-01 to find expensive indexing operations and address the root cause.
When the write thread pool queue builds up, new indexing requests wait behind work already running. A short burst can follow a traffic spike. A persistent queue more often means slow indexing, hot shards, or undersized nodes.
If the queue stays high, indexing can be rejected and searches on the same node can slow down.