What is nodetool info say for your memory? (we hit that one with memory near the max and it slowed down our system big time…still working on resolving it too).
Do any logs have the hit 0.75, running compaction OR worse hit 0.85 running compaction….you get that if the above is the case typically. Dean From: Tom Martin <tompo...@gmail.com<mailto:tompo...@gmail.com>> Reply-To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <user@cassandra.apache.org<mailto:user@cassandra.apache.org>> Date: Monday, March 4, 2013 10:31 AM To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <user@cassandra.apache.org<mailto:user@cassandra.apache.org>> Subject: Poor read latency Hi all, We have a small (3 node) cassandra cluster on aws. We have a replication factor of 3, a read level of local_quorum and are using the ephemeral disk. We're getting pretty poor read performance and quite high read latency in cfstats. For example: Column Family: AgentHotel SSTable count: 4 Space used (live): 829021175 Space used (total): 829021175 Number of Keys (estimate): 2148352 Memtable Columns Count: 0 Memtable Data Size: 0 Memtable Switch Count: 0 Read Count: 67204 Read Latency: 23.813 ms. Write Count: 0 Write Latency: NaN ms. Pending Tasks: 0 Bloom Filter False Positives: 50 Bloom Filter False Ratio: 0.00201 Bloom Filter Space Used: 7635472 Compacted row minimum size: 259 Compacted row maximum size: 4768 Compacted row mean size: 873 For comparison we have a similar set up in another cluster for an old project (hosted on rackspace) where we're getting sub 1ms read latencies. We are using multigets on the client (Hector) but are only requesting ~40 rows per request on average. I feel like we should reasonably expect better performance but perhaps I'm mistaken. Is there anything super obvious we should be checking out?
