System Tables

Page	Description
system.licenses	System table containing licenses of third-party libraries that are located in the contrib directory of ClickHouse sources.
system.merge_tree_settings	System table containing information about settings for MergeTree tables.
system.merges	System table containing information about merges and part mutations currently in process for tables in the MergeTree family.
system.metric_log	System table containing history of metrics values from tables system.metrics and system.events, periodically flushed to disk.
system.metrics	System table containing metrics which can be calculated instantly, or have a current value.
system.moves	System table containing information about in-progress data part moves of MergeTree tables. Each data part movement is represented by a single row.
system.mutations	System table containing information about mutations of MergeTree tables and their progress. Each mutation command is represented by a single row.
system.numbers	System table containing a single UInt64 column named number that contains almost all the natural numbers starting from zero.
system.numbers_mt	System table similar to system.numbers but reads are parallelized and numbers can be returned in any order.
system.one	System table containing a single row with a single dummy UInt8 column containing the value 0. Similar to the DUAL table found in other DBMSs.
system.opentelemetry_span_log	System table containing information about trace spans for executed queries.
System Tables Overview	Overview of what system tables are and why they are useful.
system.part_log	System table containing information about events that occurred with data parts in the MergeTree family tables, such as adding or merging of data.
system.parts
system.parts_columns	System table containing information about parts and columns of MergeTree tables.
system.processes	System table used for implementing the SHOW PROCESSLIST query.
system.processors_profile_log	System table containing profiling information on the processors level (which can be found in EXPLAIN PIPELINE)
system.processors_profile_log	System table containing information about existing projections in all tables.
system.query_cache	System table which shows the content of the query cache.
system.query_log	System table containing information about executed queries, for example, start time, duration of processing, error messages.
system.query_metric_log	System table containing a history of memory and metric values from table system.events for individual queries, periodically flushed to disk.
system.query_thread_log	System table containing information about threads that execute queries, for example, thread name, thread start time, duration of query processing.
system.query_views_log	System table containing information about the dependent views executed when running a query, for example, the view type or the execution time.
system.quota_limits	System table containing information about maximums for all intervals of all quotas. Any number of rows or zero can correspond to one quota.
system.quota_usage	System table containing formation about quota usage by the current user such as how much of the quota is used and how much is left.
system.quotas	System table containing information about quotas.
system.quotas_usage	System table containing formation about quota usage by all users.
system.replicas	System table containing information about and status of replicated tables residing on the local server. Useful for monitoring.
system.replicated_fetches	System table containing information about currently running background fetches.
system.replication_queue	System table containing information about tasks from replication queues stored in ClickHouse Keeper, or ZooKeeper, for tables in the ReplicatedMergeTree family.
system.system.resources	System table containing information about resources residing on the local server with one row for every resource.
system.role_grants	System table containing the role grants for users and roles.
system.roles	System table containing information about configured roles.
system.row_policies	System table containing filters for one particular table, as well as a list of roles and/or users which should use this row policy.
system.s3_queue_settings	System table containing information about the settings of S3Queue tables. Available from server version 24.10.
system.scheduler	System table containing information about and status of scheduling nodes residing on the local server.
system.schema_inference_cache	System table containing information about all cached file schemas.
system.server_settings	System table containing formation about global settings for the server, which are specified in config.xml.
system.session_log	System table containing information about all successful and failed login and logout events.
system.settings	System table containing information about session settings for current user.
system.settings_changes	System table containing information about setting changes in previous ClickHouse versions.
system.settings_profile_elements	System table which describes the content of the settings profile: constraints, roles and users that the setting applies to, parent settings profiles.
system.settings_profiles	System table which contains properties of configured setting profiles.
system.stack_trace	System table which contains stack traces of all server threads. Allows developers to introspect the server state.
system.storage_policies	System table containing information about storage policies and volumes which are defined in server configuration.
system.symbols	System table useful for C++ experts and ClickHouse engineers containing information for introspection of the clickhouse binary.
system.table_engines	System table containing descriptions of table engines supported by the server and the features they support.
system.tables	System table containing metadata of each table that the server knows about.
system.text_log	System table containing logging entries.
system.time_zones	System table containing a list of time zones that are supported by the ClickHouse server.
system.trace_log	System table containing stack traces collected by the sampling query profiler.
system.user_processes	System table containing information useful for an overview of memory usage and ProfileEvents of users.
system.users	System table containing a list of user accounts configured on the server.
system.view_refreshes	System table containing information about Refreshable Materialized Views.
system.workloads	System table containing information for workloads residing on the local server.
system.zookeeper	System table which exists only if ClickHouse Keeper or ZooKeeper are configured. It exposes data from the Keeper cluster defined in the config.
system.zookeeper_connection	System table which exists only if ZooKeeper is configured. Shows current connections to ZooKeeper (including auxiliary ZooKeepers).
system.zookeeper_log	System table containing information about the parameters of the request to the ZooKeeper server and the response from it.
system.asynchronous_insert_log	System table containing information about async inserts. Each entry represents an insert query buffered into an async insert query.
system.asynchronous_inserts	System table containing information about pending asynchronous inserts in queue.
system.asynchronous_loader	System table containing information about and status of recent asynchronous jobs (e.g. for tables which are loading). The table contains a row for every job.
system.asynchronous_metric_log	System table containing historical values for system.asynchronous_metrics, which are saved once per time interval (one second by default)
system.asynchronous_metrics	System table containing metrics that are calculated periodically in the background. For example, the amount of RAM in use.
system.azure_queue_settings	System table containing information about settings of AzureQueue tables. Available from server version 24.10.
system.backup_log	System table containing logging entries with information about BACKUP and RESTORE operations.
system.blob_storage_log	System table containing logging entries with information about various blob storage operations such as uploads and deletes.
system.build_options	System table containing information about ClickHouse server's build options.
system.clusters	System table containing information about clusters available in the config file and the servers defined in them.
system.columns	System table containing information about columns in all tables
system.contributors	System table containing information about contributors.
system.crash_log	System table containing information about stack traces for fatal errors.
system.current_roles	System table containing active roles for the current user.
system.dashboards	Contains queries used by /dashboard page accessible though the HTTP interface. useful for monitoring and troubleshooting.
system.data_skipping_indices	System table containing information about existing data skipping indices in all the tables.
system.data_type_families	System table containing information about supported data types
system.database_engines	System table containing a list of database engines supported by the server.
system.databases	System table containing information about the databases that are available to the current user.
system.detached_parts	System table containing information about detached parts of MergeTree tables
system.detached_tables	System table containing information about each detached table.
system.dictionaries	System table containing information about dictionaries
system.disks	System table containing information about disks defined in the server configuration
system.distributed_ddl_queue	System table containing information about distributed ddl queries (queries using the ON CLUSTER clause) that were executed on a cluster.
system.distribution_queue	System table containing information about local files that are in the queue to be sent to the shards.
system.dns_cache	System table containing information about cached DNS records.
system.dropped_tables	System table containing information about tables that drop table has been executed on but for which data cleanup has not yet been performed
system.dropped_tables_parts	System table containing information about parts of MergeTree dropped tables from system.dropped_tables
system.enabled_roles	System table containing all active roles at the moment, including the current role of the current user and the granted roles for the current role
system.error_log	System table containing the history of error values from table system.errors, periodically flushed to disk.
system.errors	System table containing error codes with the number of times they have been triggered.
system.events	System table containing information about the number of events that have occurred in the system.
system.functions	System table containing information about normal and aggregate functions.
system.grants	System table showing which privileges are granted to ClickHouse user accounts.
system.graphite_retentions	System table containing information about parameters graphite_rollup which are used in tables with GraphiteMergeTree type engines.
system.INFORMATION_SCHEMA	System database providing an almost standardized DBMS-agnostic view on metadata of database objects.
system.jemalloc_bins	System table containing information about memory allocations done via jemalloc allocator in different size classes (bins) aggregated from all arenas.
system.kafka_consumers	System table containing information about Kafka consumers.
system.latency_buckets	System table containing information about bucket bounds used by latency_log.
system.latency_log	Contains the history of all latency buckets, periodically flushed to disk.