Cassandra Reference
Quick reference for Apache Cassandra.
Ports
| Port |
Protocol |
Purpose |
| 9042 |
CQL |
Native client connections (TLS configured via client_encryption_options) |
| 7000 |
TCP |
Inter-node communication (TLS configured via server_encryption_options) |
| 7199 |
JMX |
JMX monitoring |
Deprecated Ports
- Port 9142 (
native_transport_port_ssl) was deprecated in Cassandra 4.x and removed in 5.0. TLS is now configured on the standard 9042 port.
- Port 7001 (
ssl_storage_port) is deprecated. Internode TLS is configured on the standard 7000 port.
Directories
| Directory |
Purpose |
/var/lib/cassandra/data |
SSTable data |
/var/lib/cassandra/commitlog |
Commit log |
/var/lib/cassandra/saved_caches |
Key/row cache |
/var/lib/cassandra/hints |
Hinted handoff |
/etc/cassandra/ |
Configuration |
/var/log/cassandra/ |
Logs |
Configuration Files
| File |
Purpose |
cassandra.yaml |
Main configuration |
cassandra-env.sh |
Environment variables |
jvm11-server.options |
JVM settings |
cassandra-rackdc.properties |
DC/rack configuration |
logback.xml |
Logging configuration |
Consistency Levels
| Level |
Description |
| ANY |
One response (including hints) |
| ONE |
One replica |
| TWO |
Two replicas |
| THREE |
Three replicas |
| QUORUM |
Majority of replicas |
| LOCAL_QUORUM |
Majority in local DC |
| EACH_QUORUM |
Majority in each DC |
| ALL |
All replicas |
| LOCAL_ONE |
One in local DC |
| SERIAL |
Serial consistency (LWT) |
| LOCAL_SERIAL |
Local serial (LWT) |
nodetool status # Cluster status
nodetool info # Node info
nodetool tpstats # Thread pools
nodetool tablestats ks # Table stats
nodetool compactionstats # Compaction status
nodetool repair -pr ks # Primary range repair
nodetool flush ks # Flush memtables
nodetool drain # Prepare for shutdown
nodetool snapshot # Create backup
nodetool describecluster # Cluster info
CQL Quick Reference
-- Keyspace
CREATE KEYSPACE ks WITH replication = {
'class': 'NetworkTopologyStrategy', 'dc1': 3
};
-- Table
CREATE TABLE ks.users (
user_id UUID PRIMARY KEY,
name TEXT
);
-- CRUD
INSERT INTO ks.users (user_id, name) VALUES (uuid(), 'John');
SELECT * FROM ks.users WHERE user_id = ?;
UPDATE ks.users SET name = 'Jane' WHERE user_id = ?;
DELETE FROM ks.users WHERE user_id = ?;
Data Types
| Type |
Description |
UUID |
128-bit unique identifier |
TIMEUUID |
Time-based UUID |
TEXT |
UTF-8 string |
INT |
32-bit integer |
BIGINT |
64-bit integer |
FLOAT |
32-bit floating point |
DOUBLE |
64-bit floating point |
BOOLEAN |
true/false |
TIMESTAMP |
Date and time |
DATE |
Date only |
BLOB |
Binary data |
LIST<T> |
Ordered collection |
SET<T> |
Unique collection |
MAP<K,V> |
Key-value pairs |
Apache Cassandra Project Resources
Official Resources
Source Code and Development
Issue Tracking and Enhancement Proposals
Mailing Lists
Blogs and News
Next Steps