Configuration¶

The configuration virtual tables provide CQL access to runtime settings, JVM system properties, and system logs without requiring shell access.

Overview¶

These tables expose Cassandra's configuration state:

Table	Purpose
`settings`	Current cassandra.yaml settings (runtime values)
`system_properties`	JVM system properties
`system_logs`	Recent Cassandra log entries

settings¶

Exposes current Cassandra configuration settings as key-value pairs. This reflects the active runtime configuration, which may differ from cassandra.yaml if settings were changed dynamically.

Schema¶

VIRTUAL TABLE system_views.settings (
    name text PRIMARY KEY,
    value text
) WITH comment = 'current settings';

Column	Type	Description
`name`	text	Configuration parameter name
`value`	text	Current value (as string)

Equivalent nodetool command: nodetool getconfig (Cassandra 5.0+)

Example Queries¶

-- All settings
SELECT name, value FROM system_views.settings;

Filter in application by name pattern (e.g., names containing 'compaction', 'timeout', 'heap').

Common Configuration Checks¶

-- Cluster identification
SELECT name, value FROM system_views.settings
WHERE name IN ('cluster_name', 'num_tokens', 'partitioner');

-- Network configuration
SELECT name, value FROM system_views.settings
WHERE name IN ('listen_address', 'rpc_address', 'broadcast_address',
               'native_transport_port', 'storage_port');

-- Compaction settings
SELECT name, value FROM system_views.settings
WHERE name IN ('compaction_throughput_mb_per_sec', 'concurrent_compactors',
               'compaction_large_partition_warning_threshold_mb');

-- Read/write settings
SELECT name, value FROM system_views.settings
WHERE name IN ('read_request_timeout', 'write_request_timeout',
               'range_request_timeout', 'counter_write_request_timeout');

-- Hinted handoff
SELECT name, value FROM system_views.settings
WHERE name IN ('hinted_handoff_enabled', 'max_hint_window',
               'hinted_handoff_throttle_in_kb', 'max_hints_delivery_threads');

-- Commit log
SELECT name, value FROM system_views.settings
WHERE name IN ('commitlog_sync', 'commitlog_sync_period',
               'commitlog_segment_size', 'commitlog_total_space');

-- Memtable configuration
SELECT name, value FROM system_views.settings
WHERE name IN ('memtable_heap_space', 'memtable_offheap_space',
               'memtable_allocation_type', 'memtable_flush_writers');

Configuration Audit¶

-- Check authentication/authorization settings
SELECT name, value FROM system_views.settings
WHERE name IN ('authenticator', 'authorizer', 'role_manager',
               'server_encryption_options', 'client_encryption_options');

Security check: Verify authenticator is not AllowAllAuthenticator and authorizer is not AllowAllAuthorizer in production.

system_properties¶

Exposes JVM system properties relevant to Cassandra. Useful for verifying JVM configuration without shell access.

Schema¶

VIRTUAL TABLE system_views.system_properties (
    name text PRIMARY KEY,
    value text
) WITH comment = 'Cassandra relevant system properties';

Column	Type	Description
`name`	text	System property name
`value`	text	Property value

Example Queries¶

-- All system properties
SELECT name, value FROM system_views.system_properties;

Filter in application by name prefix (e.g., 'java.', 'cassandra.', 'os.').

Common Property Checks¶

-- JVM version
SELECT name, value FROM system_views.system_properties
WHERE name IN ('java.version', 'java.vendor', 'java.vm.name', 'java.vm.version');

-- Cassandra paths
SELECT name, value FROM system_views.system_properties
WHERE name IN ('cassandra.config', 'cassandra.storagedir', 'cassandra.logdir');

-- Operating system
SELECT name, value FROM system_views.system_properties
WHERE name IN ('os.name', 'os.version', 'os.arch');

-- User and file encoding
SELECT name, value FROM system_views.system_properties
WHERE name IN ('user.name', 'user.home', 'user.dir', 'file.encoding');

For GC settings and heap configuration, query all properties and filter in application.

system_logs¶

Provides access to recent Cassandra log entries via CQL. Available in Cassandra 5.0+.

Schema¶

VIRTUAL TABLE system_views.system_logs (
    timestamp timestamp,
    order_in_millisecond int,
    level text,
    logger text,
    message text,
    PRIMARY KEY (timestamp, order_in_millisecond)
) WITH CLUSTERING ORDER BY (order_in_millisecond ASC)
    AND comment = 'Cassandra logs';

Column	Type	Description
`timestamp`	timestamp	Log entry timestamp
`order_in_millisecond`	int	Ordering within same millisecond
`level`	text	Log level (ERROR, WARN, INFO, DEBUG, TRACE)
`logger`	text	Logger name (class/component)
`message`	text	Log message content

Example Queries¶

-- All log entries
SELECT timestamp, level, logger, message
FROM system_views.system_logs;

-- Error messages
SELECT timestamp, logger, message
FROM system_views.system_logs
WHERE level = 'ERROR';

-- Warnings and errors
SELECT timestamp, level, logger, message
FROM system_views.system_logs
WHERE level IN ('ERROR', 'WARN');

Troubleshooting Queries¶

-- All log entries
SELECT timestamp, level, logger, message
FROM system_views.system_logs;

Filter in application by logger name or message content (e.g., 'Compaction', 'OutOfMemory').

Monitoring Use Cases¶

Configuration Drift Detection¶

-- Export current settings for comparison
-- Run on each node and compare results
SELECT name, value FROM system_views.settings;

Exclude node-specific values (containing 'address') when comparing across nodes.

Security Audit¶

-- Authentication configuration
SELECT name, value FROM system_views.settings
WHERE name IN ('authenticator', 'authorizer', 'role_manager',
               'permissions_validity', 'credentials_validity');

-- Encryption settings
SELECT name, value FROM system_views.settings
WHERE name IN ('server_encryption_options', 'client_encryption_options',
               'native_transport_port_ssl');

-- Audit settings (Cassandra 4.0+)
SELECT name, value FROM system_views.settings
WHERE name IN ('audit_logging_options');

Performance Configuration Review¶

-- Thread pool sizing (compare with thread_pools table)
SELECT name, value FROM system_views.settings
WHERE name IN ('concurrent_reads', 'concurrent_writes',
               'concurrent_counter_writes', 'concurrent_compactors');

-- Cache settings (compare with caches table)
SELECT name, value FROM system_views.settings
WHERE name IN ('key_cache_size_in_mb', 'row_cache_size_in_mb',
               'counter_cache_size_in_mb');

-- Throughput settings
SELECT name, value FROM system_views.settings
WHERE name IN ('compaction_throughput_mb_per_sec',
               'stream_throughput_outbound_megabits_per_sec',
               'inter_dc_stream_throughput_outbound_megabits_per_sec');

Alerting Rules¶

Configuration Warnings¶

-- Security concerns
SELECT name, value FROM system_views.settings
WHERE (name = 'authenticator' AND value = 'AllowAllAuthenticator')
   OR (name = 'authorizer' AND value = 'AllowAllAuthorizer');

Error Log Monitoring¶

-- Recent errors (for alerting integration)
SELECT timestamp, logger, message
FROM system_views.system_logs
WHERE level = 'ERROR';

Filter in application for entries within the last 5 minutes.

Comparison with nodetool¶

Information	nodetool Command	Virtual Table Query
View settings	`nodetool getconfig`	`SELECT * FROM system_views.settings`
Specific setting	`nodetool getconfig <name>`	`SELECT value FROM system_views.settings WHERE name = '<name>'`
System properties	N/A (check JVM)	`SELECT * FROM system_views.system_properties`
Logs	Filesystem access	`SELECT * FROM system_views.system_logs`

Limitations¶

Settings table
Read-only; use nodetool setconfig for runtime changes
Values are strings; type conversion may be needed
Some settings require restart to change
System properties
Reflects JVM startup properties
Cannot be modified at runtime
System logs
Limited retention (recent entries only)
May not include all log levels depending on configuration
For full log history, use filesystem access or log aggregation

Virtual Tables Overview - Introduction to virtual tables
Thread Pools - Thread pool configuration and metrics
Caches - Cache configuration and hit ratios
Cassandra Configuration - Full configuration reference

Configuration¶

Overview¶

settings¶

Schema¶

Example Queries¶

Common Configuration Checks¶

Configuration Audit¶

system_properties¶

Schema¶

Example Queries¶

Common Property Checks¶

system_logs¶

Schema¶

Example Queries¶

Troubleshooting Queries¶

Monitoring Use Cases¶

Configuration Drift Detection¶

Security Audit¶

Performance Configuration Review¶

Alerting Rules¶

Configuration Warnings¶

Error Log Monitoring¶

Comparison with nodetool¶

Limitations¶

Related Documentation¶