Non-docValues Fields Causing Memory Bloat

warning

configurationUpdated Mar 4, 2024

Fields used for faceting, sorting, or grouping without docValues=true consume excessive JVM heap via fieldCache, particularly for high-cardinality fields, leading to memory pressure and potential OOM failures.

Sources

Solr Out of Memory (OOM): Causes and Solutions | SearchStax Blogwww.searchstax.com

Apache Solr Performance Tuning and Monitoringreintech.io

Technologies:

Apache SolrThe root cause of this issue originates in Apache Solr

How to detect:

Review schema for fields used in faceting, sorting, or grouping operations. Check if docValues=true is set. Monitor heap usage increases correlated with faceting queries. High memory usage with moderate query load indicates potential fieldCache issues.

Recommended action:

Update schema.xml to set docValues=true for all fields used in faceting, sorting, and grouping. Note: This requires full reindexing. Memory-map field data instead of loading into heap to reduce JVM memory requirements.