Having a problem diagnosing an issue with row caching. It seems like row caching is not working (very few items stored), despite it being enabled, using JNA, and the key cache being super hot.  I assume I'm missing something obvious, but I would expect to have more items stored in the row cache, even after updates. Is there something in the logs I should look for? Are writes invalidating the cache?

Here are the stats:

keys: 100 bytes, values: 200 - 400 bytes, with read and write pattern

Single node, Cassandra 1.1.5, test node


Keyspace: <omitted>
Read Count: 15967248
Read Latency: 0.4956699828924809 ms.
Write Count: 15967240
Write Latency: 0.027375880803445052 ms.
Pending Tasks: 0
Column Family:  <omitted>
SSTable count: 75
Space used (live): 705364536
Space used (total): 705364536
Number of Keys (estimate): 2591104
Memtable Columns Count: 267840
Memtable Data Size: 129949276
Memtable Switch Count: 192
Read Count: 15967248
Read Latency: NaN ms.
Write Count: 15967240
Write Latency: NaN ms.
Pending Tasks: 0
Bloom Filter False Postives: 281
Bloom Filter False Ratio: 0.00000
Bloom Filter Space Used: 3986944
Compacted row minimum size: 311
Compacted row maximum size: 642
Compacted row mean size: 419


Load             : 676.5 MB
Heap Memory (MB) : 1476.10 / 2925.00
Key Cache    : size 104857584 (bytes), capacity 104857584 (bytes), 6146639 hits, 14680951 requests, 1.000 recent hit rate, 14400 save period in seconds
Row Cache  : size 0 (bytes), capacity 209715200 (bytes), 47 hits, 14400100 requests, NaN recent hit rate, 87000 save period in seconds