scylladb

Start CQL shell

$ cqlsh

$ cqlsh [hostname] [9042]

$ cqlsh -u [username] -p [password]

$ cqlsh -f [script.cql]

$ nodetool status

$ scylla --version

$ nodetool describecluster

$ nodetool flush

cqlsh [options] [host] [port]
nodetool [options] command [args]

ScyllaDB uses Cassandra-compatible tools (cqlsh and nodetool) with the same commands and CQL syntax. ScyllaDB is a C++ rewrite of Cassandra designed for lower latency and higher throughput.
cqlsh executes CQL statements. Keyspaces, tables, and query syntax match Cassandra. ScyllaDB adds lightweight transactions (LWT) improvements and materialized views.
nodetool manages cluster operations. ScyllaDB extends it with toppartitions for identifying hot spots that cause load imbalance.
ScyllaDB's shard-per-core architecture eliminates locking between CPU cores. The --smp flag controls core allocation. Configuration differs from Cassandra, using scylla.yaml.
ScyllaDB Alternator provides DynamoDB-compatible API, accessible via AWS SDK tools instead of cqlsh.

/etc/scylla/scylla.yaml

Main ScyllaDB configuration file for cluster settings, networking, storage, and tuning parameters.

Datacenter and rack configuration for topology-aware replication.

CQL shell configuration file for connection defaults, formatting, and authentication.

-u, --username user

Authentication username.

Authentication password.

Initial keyspace.

Execute CQL file.

Execute single CQL statement.

Use SSL connection.

Query timeout.

status

Show cluster node status.

Node information and metrics.

Token ring information.

Run repair operation.

Force compaction.

Flush memtables to SSTables.

Take snapshot backup.

Drain node for shutdown.

Show ScyllaDB version.

Cluster information.

Show hot partitions.

nodetool toppartitions keyspace table duration

Identify hot partitions causing load.

Adjust logging dynamically.

Development mode flag.

Number of CPU cores to use.

Memory allocation.

While CQL-compatible, some Cassandra features differ or are unsupported. Configuration files differ from Cassandra. Repair is faster but still resource-intensive. Check compatibility matrix for drivers.

ScyllaDB was founded in 2015 by Avi Kivity (KVM creator) and Dor Laor. The first release came in 2015 as a drop-in Cassandra replacement written in C++ using the Seastar framework. Version 2.0 (2017) added materialized views. ScyllaDB Open Source is Apache-licensed; Enterprise adds features like encryption and LDAP.

cqlsh(1), nodetool(1), cassandra(1)