mongodb memory_error ai_generated true

WiredTiger cache full: eviction falling behind

ID: mongodb/wiredtiger-cache-full

Also available as: JSON · Markdown
78%Fix Rate
82%Confidence
3Evidence
2023-01-01First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
7 active — — —

Root Cause

WiredTiger cache under pressure, eviction cant keep up.

generic

Workarounds

  1. 88% success Set cacheSizeGB to 50% of RAM minus 1GB (default heuristic)
  2. 85% success Reduce working set size with better indexes and query optimization

Dead Ends

Common approaches that don't work:

  1. Set cacheSizeGB to all available RAM 82% fail

    OS and other processes starved

  2. Restart mongod on high cache usage 72% fail

    Temporary fix, same problem returns