CPU Saturation Masking Simple Query Performance

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Resource ContentionUpdated Mar 19, 2025

Simple, inexpensive queries (e.g., single-term searches) become slow when CPU is saturated by other operations like indexing spikes, causing queries that should complete in <100ms to take 400ms+.

Sources

Troubleshooting Solr Slow Queries Using Logs and Metrics - Sematextsematext.com

Technologies:

Apache SolrSymptoms of this issue are visible in Apache Solr metrics and logs

How to detect:

Detect when query latency (QTime) increases significantly (2-4x baseline) while CPU utilization approaches 100%, but query complexity remains constant. Correlate query slowness with indexing rate spikes or other CPU-intensive operations.

Recommended action:

Rate-limit indexing operations from the application layer, add compute capacity to the Solr cluster, or schedule bulk indexing during off-peak hours to prevent CPU contention with query workload.