Querying a system table

Details about Cassandra database objects and cluster configuration in the system keyspace tables.

The system keyspace includes a number of tables that contain details about your Cassandra database objects and cluster configuration.

Cassandra populates these tables and others in the system keyspace.
Table 1. Columns in System Tables
Table name Column name Comment
available_ranges keyspace_name, ranges
batches id, mutations, version
batchlog id, data, version, written_at
built_views keyspace_name, view_name Information on materialized views
compaction_history id, bytes_in, bytes_out, columnfamily_name, compacted_at, keyspace_name, rows_merged Information on compaction history
hints target_id, hint_id, message_version, mutation
"IndexInfo" table_name, index_name Information on indexes
local key, bootstrapped, broadcast_address, cluster_name, cql_version, data_center, gossip_generation, host_id, listen_address, native_protocol_version, partitioner, rack, release_version, rpc_address, schema_version, thrift_version, tokens, truncated_at map Information on a node has about itself and a superset of gossip.
paxos row_key, cf_id, in_progress_ballot, most_recent_commit, most_recent_commit_at, most_recent_commit_version, proposal, proposal_ballot, proposal_version Information on lightweight Paxos transactions
peers peer, data_center, host_id, preferred_ip, rack, release_version, rpc_address, schema_version, tokens Each node records what other nodes tell it about themselves over the gossip.
peer_events peer, hints_dropped
range_xfers token_bytes,requested_at
size_estimates keyspace_name, table_name, range_start, range_end, mean_partition_size, partitions_count Information on partitions
sstable_activity keyspace_name, columnfamily_name, generation, rate_120m, rate_15m
views_builds_in_progress keyspace_name, view_name, generation_number, last_token
Cassandra populates these tables in the system_schema keyspace.
Table 2. Columns in System_Schema Tables
Table name Column name Comment
aggregates keyspace_name, aggregate_name, argument_types, final_func, initcond, return_type, state_func, state_type Information about user-defined aggregates
columns keyspace_name, table_name, column_name, clustering_order, column_name_bytes, kind, position, type Information about table columns
dropped_columns keyspace_name, table_name, column_name, dropped_time,type Information about dropped columns
functions keyspace_name, function_name, argument_types, argument_names, body, called_on_null_input,language,return_type Information on user-defined functions
indexes keyspace_name, table_name, index_name, kind,options Information about indexes
keyspaces keyspace_name, durable_writes, replication Information on keyspace durable writes and replication
tables keyspace_name, table_name, bloom_filter_fp_chance, caching, comment, compaction, compression, crc_check_chance, dclocal_read_repair_chance, default_time_to_live, extensions, flags, gc_grace_seconds, id, max_index_interval, memtable_flush_period_in_ms, min_index_interval, read_repair_chance, speculative_retry Information on columns and column indexes. Used internally for compound primary keys.
triggers keyspace_name, table_name, trigger_name, options Information on triggers
types keyspace_name, type_name, field_names, field_types Information about user-defined types
views keyspace_name, view_name, base_table_id, base_table_name, bloom_filter_fp_chance, caching, comment, compaction, compression, crc_check_chance, dclocal_read_repair_chance, default_time_to_live, extensions, flags,gc_grace_seconds, include_all_columns, max_index_interval, memtable_flush_period_in_ms, min_index_interval, read_repair_chance, speculative_retry, where_clause Information about materialized views