시스템 테이블

시스템 테이블이 무엇인지와 왜 유용한지에 대한 개요입니다.

페이지	설명
system.constraints	System table containing information about existing constraints in all tables.
System Tables Overview	Overview of what system tables are and why they are useful.
INFORMATION_SCHEMA	System database providing an almost standardized DBMS-agnostic view on metadata of database objects.
system.aggregate_function_combinators	Contains a list of all available aggregate function combinators, which could be applied to aggregate functions and change the way they work.
system.aggregated_zookeeper_log	System table containing aggregated statistics of ZooKeeper operations grouped by session, path, operation type, component, and subrequest flag.
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_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_inserts	System table containing information about pending asynchronous inserts in queue.
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.azure_queue_metadata_cache	Contains in-memory state of AzureQueue metadata and currently processed rows per file.
system.azure_queue_log	Contains log entries with information about files processed by the AzureQueue engine.
It is safe to truncate or drop this table at any time.
system.background_schedule_pool_log	System table containing history of background schedule pool task executions.
system.background_schedule_pool	System table containing information about tasks in background schedule pools.
system.backup_log	System table containing logging entries with information about BACKUP and RESTORE operations.
system.backups	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.certificates	Contains information about available certificates and their sources.
system.clusters	System table containing information about clusters available in the config file and the servers defined in them.
system.codecs	System table containing information about codecs in queue.
system.collations	Contains a list of all available collations for alphabetical comparison of strings.
system.columns	System table containing information about columns in all tables
system.completions	Contains a list of completion tokens.
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_skipping_index_types	System table containing a list of data skipping index types supported by the server along with their embedded documentation.
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.database_replicas	System table containing information about and status of replicated database.
system.databases	System table containing information about the databases that are available to the current user.
system.dead_letter_queue	System table containing information about messages received via a streaming engine and parsed with errors.
system.delta_lake_metadata_log	System table containing information about metadata files read from Delta Lake tables. Each entry represents a root metadata JSON file.
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.dictionary_sources	System table containing a list of dictionary sources supported by the server along with their embedded documentation.
system.dictionary_layouts	System table containing a list of dictionary layouts supported by the server along with their embedded documentation.
system.dimensional_metrics	This table contains dimensional metrics that can be calculated instantly and exported in the Prometheus format. It is always up to date.
system.disk_types	System table containing a list of disk types supported by the server along with their embedded documentation.
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.documentation	System table that collects the embedded documentation of the uniform components of the system (functions, table engines, data types, and so on) into a single table, with the reference documentation rendered as Markdown.
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.fail_points	Contains a list of all available failpoints with their type and current status.
system.filesystem_cache_settings	Contains information about all filesystem cache settings
system.filesystem_read_prefetches_log	Contains a history of all prefetches done during reading from MergeTree tables backed by a remote filesystem.
It is safe to truncate or drop this table at any time.
system.filesystem_cache_log	Contains a history of all events occurred with filesystem cache for objects on a remote filesystem.
It is safe to truncate or drop this table at any time.
system.filesystem_cache	Contains information about all entries inside filesystem cache for remote objects.
system.formats	Contains a list of all the formats along with flags whether a format is suitable for input/output or whether it supports parallelization.
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.histogram_metrics	This table contains histogram metrics that can be calculated instantly and exported in the Prometheus format. It is always up to date.
system.iceberg_history	System iceberg snapshot history
system.iceberg_files	System table containing per-file metadata of Iceberg tables
system.iceberg_metadata_log	System table containing information about metadata files read from Iceberg tables. Each entry represents either a root metadata file, metadata extracted from an Avro file, or an entry of some Avro file.
system.instrumentation	System table containing the instrumentation points
system.jemalloc_stats	Returns jemalloc statistics in a single row with a single column. Equivalent to SYSTEM JEMALLOC STATS command.
system.jemalloc_bins	System table containing information about memory allocations done via jemalloc allocator in different size classes (bins) aggregated from all arenas.
system.jemalloc_profile_text	Displays the symbolized jemalloc heap profile. Run ‘SYSTEM JEMALLOC FLUSH PROFILE’ to generate a profile first.
system.kafka_consumers	System table containing information about Kafka consumers.
system.keeper_cluster	System table which exists only when this node runs an in-process ClickHouse Keeper. Contains one row per Raft cluster member as seen by this Keeper.
system.keeper_snapshots	System table which exists only when this node runs an in-process ClickHouse Keeper. Contains one row per on-disk Raft snapshot tracked by the Keeper state machine.
system.keeper_changelogs	System table which exists only when this node runs an in-process ClickHouse Keeper. Contains one row per on-disk Raft changelog file tracked by the Keeper log store.
system.keywords	Contains a list of all keywords used in ClickHouse parser.
system.licenses	System table containing licenses of third-party libraries that are located in the contrib directory of ClickHouse sources.
system.macros	Contains a list of all macros defined in server configuration.
system.masking_policies	System table containing information about all masking policies in the system.
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.models	Contains a list of CatBoost models loaded into a LibraryBridge’s memory along with time when it was loaded.
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.named_collections	SQL query로 생성되었거나 설정 파일에서 파싱된 모든 이름이 지정된 컬렉션 목록을 포함합니다.
system.numbers_mt	system.numbers와 유사한 system table이지만, 읽기가 병렬화되며 숫자는 임의의 순서로 반환될 수 있습니다.
system.numbers	number라는 이름의 단일 UInt64 컬럼을 포함하는 system table이며, 0부터 시작하는 거의 모든 자연수를 담고 있습니다.
system.one	값 0을 포함하는 단일 dummy UInt8 컬럼이 있는 단일 행을 포함하는 system table입니다. 다른 DBMS의 DUAL 테이블과 유사합니다.
system.opentelemetry_span_log	실행된 쿼리의 trace spans 정보를 포함하는 system table입니다.
system.part_moves_between_shards	현재 세그먼트 간 이동 중인 파트와 그 진행 상황 정보를 포함합니다.
system.part_log	데이터 추가 또는 머지와 같이 MergeTree 엔진 계열 테이블의 데이터 파트에서 발생한 이벤트 정보를 포함하는 system table입니다.
system.parts	MergeTree의 파트 정보를 포함하는 system table입니다.
system.parts_columns	MergeTree 테이블의 파트 및 컬럼 정보를 포함하는 system table입니다.
system.predicate_statistics_log	쿼리 실행 중 MergeTree 읽기 파이프라인에서 수집된 샘플링된 필터와 인덱스 선택도 통계를 담은 시스템 테이블입니다.
system.primes	prime이라는 이름의 단일 UInt64 컬럼이 있으며, 2부터 시작하는 소수가 오름차순으로 포함된 시스템 테이블입니다.
system.privileges	사용자 또는 역할에 권한 부여할 수 있는 모든 권한 목록을 포함합니다.
system.processes	SHOW PROCESSLIST 쿼리를 구현하는 데 사용되는 시스템 테이블입니다.
system.processors_profile_log	프로세서 수준(EXPLAIN PIPELINE에서 확인 가능)의 프로파일링 정보를 담은 시스템 테이블입니다.
system.projection_parts_columns	MergeTree 엔진 계열 테이블의 프로젝션 파트에 있는 컬럼 정보를 담은 시스템 테이블입니다.
system.projection_parts	MergeTree 엔진 계열 테이블의 프로젝션 파트 정보를 담은 시스템 테이블입니다.
system.projections	모든 테이블에 존재하는 프로젝션 정보를 담은 시스템 테이블입니다.
system.query_views_log	쿼리 실행 시 함께 실행되는 종속 뷰의 정보(예: 뷰 유형, 실행 시간)를 담은 시스템 테이블입니다.
system.query_condition_cache	쿼리 조건 캐시의 내용을 보여주는 시스템 테이블입니다.
system.query_thread_log	쿼리를 실행하는 스레드의 정보(예: 스레드 이름, 스레드 시작 시간, 쿼리 처리 시간)를 담은 시스템 테이블입니다.
system.query_metric_log	개별 쿼리에 대한 system.events 테이블의 메모리 및 메트릭 값 이력을 담고 있으며, 이 값들은 주기적으로 디스크에 기록되는 시스템 테이블입니다.
system.query_log	실행된 쿼리의 정보(예: 시작 시간, 처리 시간, 오류 메시지)를 담은 시스템 테이블입니다.
system.query_cache	쿼리 캐시의 내용을 보여주는 시스템 테이블입니다.
system.quota_usage	현재 사용자의 쿼터 사용량 정보(예: 사용한 양과 남은 양)를 담은 시스템 테이블입니다.
system.quota_limits	모든 쿼터의 모든 기간에 대한 최대값 정보를 담은 시스템 테이블입니다. 하나의 쿼터에 여러 개의 행이 대응될 수도 있고, 행이 없을 수도 있습니다.
system.quotas_usage	모든 사용자의 쿼터 사용량 정보를 담은 시스템 테이블입니다.
system.quotas	쿼터 정보를 담은 시스템 테이블입니다.
system.remote_data_paths	S3 또는 Azure Blob Storage와 같은 원격 디스크에 저장된 데이터 파일 정보를 담은 시스템 테이블입니다.
system.replicas	로컬 서버에 있는 복제된 테이블의 정보와 상태를 담은 시스템 테이블입니다. 모니터링에 유용합니다.
system.replicated_merge_tree_settings	모든 ReplicatedMergeTree 엔진별 설정의 목록과 현재값, 기본값, 설명을 포함합니다. 이 설정들은 CREATE 쿼리의 SETTINGS 섹션에서 변경할 수 있습니다.
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.resources	System table containing information about resources residing on the local server with one row for every resource.
system.rocksdb	Contains a list of metrics exposed from embedded RocksDB.
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.s3queue_metadata_cache	Contains in-memory state of S3Queue metadata and currently processed rows per file.
system.s3queue_log	Contains log entries with information about files processed by the S3Queue engine.
It is safe to truncate or drop this table at any time.
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_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_changes	System table containing information about setting changes in previous ClickHouse versions.
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.table_functions	Contains a list of all available table functions with their descriptions.
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.tokenizers	System table which shows all available tokenizers.
system.trace_log	System table containing stack traces collected by the sampling query profiler.
system.transactions	Contains a list of transactions and their state.
system.transactions_info_log	Contains information about all transactions executed on a current server.
It is safe to truncate or drop this table at any time.
system.unicode	System table containing a list of Unicode characters and their properties.
system.user_processes	System table containing information useful for an overview of memory usage and ProfileEvents of users.
system.user_directories	Contains the information about configured user directories - directories on the file system from which ClickHouse server is allowed to read user provided data.
system.user_defined_functions	System table containing loading status and configuration metadata for User-Defined Functions (UDFs).
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.warnings	This table contains warning messages about clickhouse server.
system.warnings	Contains warnings about server configuration to be displayed by clickhouse-client right after it connects to the server.
system.workloads	System table containing information for workloads residing on the local server.
system.zeros	Produces unlimited number of non-materialized zeros.
system.zeros_mt	Multithreaded version of system.zeros.
system.zookeeper_watches	System table showing currently active ZooKeeper watches registered by this ClickHouse server.
system.zookeeper_info	System table which outputs introspection of all available keeper nodes.
system.zookeeper_log	System table containing information about the parameters of the request to the ZooKeeper server and the response from it.
system.zookeeper_connection	System table which exists only if ZooKeeper is configured. Shows current connections to ZooKeeper (including auxiliary ZooKeepers).
system.zookeeper_connection_log	Shows the history of ZooKeeper connections (including auxiliary ZooKeepers).
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.