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dictionaries

Querying in ClickHouse Cloud

The data in this system table is held locally on each node in ClickHouse Cloud. Obtaining a complete view of all data, therefore, requires the clusterAllReplicas function. See here for further details.

Contains information about dictionaries.

Columns:

  • database (String) — Name of the database containing the dictionary created by DDL query. Empty string for other dictionaries.
  • name (String) — Dictionary name.
  • uuid (UUID) — Dictionary UUID.
  • status (Enum8) — Dictionary status. Possible values:
    • NOT_LOADED — Dictionary was not loaded because it was not used.
    • LOADED — Dictionary loaded successfully.
    • FAILED — Unable to load the dictionary as a result of an error.
    • LOADING — Dictionary is loading now.
    • LOADED_AND_RELOADING — Dictionary is loaded successfully, and is being reloaded right now (frequent reasons: SYSTEM RELOAD DICTIONARY query, timeout, dictionary config has changed).
    • FAILED_AND_RELOADING — Could not load the dictionary as a result of an error and is loading now.
  • origin (String) — Path to the configuration file that describes the dictionary.
  • type (String) — Type of dictionary allocation. Storing Dictionaries in Memory.
  • key.names (Array(String)) — Array of key names provided by the dictionary.
  • key.types (Array(String)) — Corresponding array of key types provided by the dictionary.
  • attribute.names (Array(String)) — Array of attribute names provided by the dictionary.
  • attribute.types (Array(String)) — Corresponding array of attribute types provided by the dictionary.
  • bytes_allocated (UInt64) — Amount of RAM allocated for the dictionary.
  • query_count (UInt64) — Number of queries since the dictionary was loaded or since the last successful reboot.
  • hit_rate (Float64) — For cache dictionaries, the percentage of uses for which the value was in the cache.
  • found_rate (Float64) — The percentage of uses for which the value was found.
  • element_count (UInt64) — Number of items stored in the dictionary.
  • load_factor (Float64) — Percentage filled in the dictionary (for a hashed dictionary, the percentage filled in the hash table).
  • source (String) — Text describing the data source for the dictionary.
  • lifetime_min (UInt64) — Minimum lifetime of the dictionary in memory, after which ClickHouse tries to reload the dictionary (if invalidate_query is set, then only if it has changed). Set in seconds.
  • lifetime_max (UInt64) — Maximum lifetime of the dictionary in memory, after which ClickHouse tries to reload the dictionary (if invalidate_query is set, then only if it has changed). Set in seconds.
  • loading_start_time (DateTime) — Start time for loading the dictionary.
  • last_successful_update_time (DateTime) — End time for loading or updating the dictionary. Helps to monitor some troubles with dictionary sources and investigate the causes.
  • loading_duration (Float32) — Duration of a dictionary loading.
  • last_exception (String) — Text of the error that occurs when creating or reloading the dictionary if the dictionary couldn't be created.
  • comment (String) — Text of the comment to dictionary.

Example

Configure the dictionary:

Make sure that the dictionary is loaded.