Cassandra Useful Commands

gistfile1.txt

# Show the latency across keyspaces
nodetool cfstats | grep "Latency"

# Identify how many replicas have a row
# 1. use cassandra-cli to identify row key (connect <host>/<port>; use <keyspace>; list <table> limit 1;)
# 2. copy key into: nodetool getendpoints -- <keyspace> <table> <key>

#Node Exceptions
nodetool info | grep Exceptions

#Flappyness
egrep -oh "/.+ is now DOWN" /var/log/cassandra/system.log* | sort | uniq -c | sort -g

#Heap is too full
egrep -h "Heap size.+" /var/log/cassandra/system.log*

#Slow STW collections
egrep -oh "].+ParNew: [0-9]{5,}.+" /var/log/cassandra/system.log*