系统表

页面	描述
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_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.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.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.azure_queue_metadata_cache	Contains in-memory state of AzureQueue metadata and currently processed rows per file.
system.azure_queue_settings	System table containing information about settings of AzureQueue tables. Available from server version 24.10.
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_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.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.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.fail_points	Contains a list of all available failpoints with their type and current status.
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_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	Contains information about all entries inside filesystem cache for remote objects.
system.filesystem_cache_settings	Contains information about all filesystem cache settings
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	包含在使用 GraphiteMergeTree 类型引擎的表中所用 graphite_rollup 参数信息的系统表。
system.histogram_metrics	该表包含可实时计算并以 Prometheus 格式导出的直方图指标，且始终保持最新。
system.iceberg_metadata_log	包含从 Iceberg 表读取的元数据文件信息的系统表。每条记录表示一个根元数据文件、从某个 Avro 文件中提取的元数据,或某个 Avro 文件对应的一条条目。
system.iceberg_history	系统中的 Iceberg 快照历史
system.instrumentation	包含插桩点信息的系统表
system.jemalloc_bins	包含通过 jemalloc 分配器在不同大小类别 (bin) 中的内存分配信息,汇总自所有 arena 的系统表。
system.jemalloc_profile_text	显示带符号信息的 jemalloc 堆分析报告。请先运行 'SYSTEM JEMALLOC FLUSH PROFILE' 生成分析报告。
system.jemalloc_stats	以单行单列的形式返回 jemalloc 统计信息。等同于 SYSTEM JEMALLOC STATS 命令。
system.kafka_consumers	包含 Kafka 消费者信息的系统表。
system.keywords	包含 ClickHouse 解析器所使用的全部关键字列表。
system.licenses	包含 ClickHouse 源代码中 contrib 目录内第三方库许可证的系统表。
system.macros	包含在服务器配置中定义的所有 macros 列表。
system.masking_policies	包含系统中所有掩码策略信息的系统表。
system.merge_tree_settings	包含 MergeTree 表设置信息的系统表。
system.merges	包含 MergeTree 系列表当前正在进行的合并和数据部件 mutation 信息的系统表。
system.metric_log	系统表，包含来自 system.metrics 和 system.events 表的指标值历史记录，并会定期刷新到磁盘。
system.metrics	包含可即时计算或具有当前值的指标的系统表。
system.models	包含已加载到 LibraryBridge 内存中的 CatBoost 模型列表及其加载时间的系统表。
system.moves	包含 MergeTree 表正在进行的数据部件移动信息的系统表。每个数据部件的移动对应一行记录。
system.mutations	包含 MergeTree 表 mutation 操作及其进度信息的系统表。每个 mutation 命令对应一行记录。
system.named_collections	包含通过 SQL 查询创建或从设置文件解析得到的所有命名集合列表。
system.numbers	系统表，仅包含一个名为 number 的 UInt64 列，该列存储几乎全部从 0 开始的自然数。
system.numbers_mt	与 system.numbers 类似的系统表，但读取操作是并行执行的，返回的数字可以是任意顺序。
system.one	仅包含一行且只有一个名为 dummy、类型为 UInt8、值为 0 的列的系统表。类似于其他数据库管理系统中的 DUAL 表。
system.opentelemetry_span_log	包含已执行查询的 trace spans 信息的系统表。
system.part_log	包含 MergeTree 系列表中数据分区片段相关事件信息的系统表,例如数据添加或合并等操作。
system.part_moves_between_shards	包含当前正在分片之间移动的 parts 及其进度信息。
system.parts	包含 MergeTree 表分区片段相关信息的系统表
system.parts_columns	包含 MergeTree 表的分区片段和列信息的系统表。
system.predicate_statistics_log	系统表，包含在查询执行期间从 MergeTree 读取管道中收集的采样过滤器和索引选择性统计信息。
system.primes	System table containing a single UInt64 column named prime that contains prime numbers in ascending order, starting from 2.
system.privileges	Contains a list of all available privileges that could be granted to a user or role.
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.projection_parts	System table containing information about projection parts for tables of the MergeTree family.
system.projection_parts_columns	System table containing information about columns in projection parts for tables of the MergeTree family
system.projections	System table containing information about existing projections in all tables.
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.query_cache	System table which shows the content of the query cache.
system.query_condition_cache	System table which shows the content of the query condition cache.
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.remote_data_paths	System table containing information about data files stored on remote disks such as S3 or Azure Blob Storage.
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.replicated_merge_tree_settings	Contains a list of all ReplicatedMergeTree engine specific settings, their current and default values along with descriptions. You may change any of them in SETTINGS section in CREATE query.
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_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.s3queue_metadata_cache	Contains in-memory state of S3Queue metadata and currently processed rows per file.
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.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_defined_functions	System table containing loading status and configuration metadata for User-Defined Functions (UDFs).
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_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.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	包含本地服务器上工作负载信息的系统表。
system.zeros	生成无限数量的非物化零值。
system.zeros_mt	system.zeros 的多线程版本。
system.zookeeper	仅在配置了 ClickHouse Keeper 或 ZooKeeper 时才存在的系统表。用于展示配置中定义的 Keeper 集群中的数据。
system.zookeeper_connection	仅在配置了 ZooKeeper 时存在的系统表。显示当前与 ZooKeeper 的连接 (包括辅助 ZooKeeper) 。
system.zookeeper_connection_log	显示 ZooKeeper 连接历史 (包括辅助 ZooKeeper) 。
system.zookeeper_info	用于输出所有可用 Keeper 节点内部状态的系统表。
system.zookeeper_log	包含关于向 ZooKeeper 服务器发送的请求参数及其返回的响应信息的系统表。
system.zookeeper_watches	显示由此 ClickHouse 服务端注册的当前处于活动状态的 ZooKeeper watches 的系统表。