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* replace exit with assert in test_single_page * improve save_raw_single_page docs option * More grammar fixes * "Built from" link in new tab * fix mistype * Example of include in docs * add anchor to meeting form * Draft of translation helper * WIP on translation helper * Replace some fa docs content with machine translation * add normalize-en-markdown.sh * normalize some en markdown * normalize some en markdown * admonition support * normalize * normalize * normalize * support wide tables * normalize * normalize * normalize * normalize * normalize * normalize * normalize * normalize * normalize * normalize * normalize * normalize * normalize * lightly edited machine translation of introdpection.md * lightly edited machhine translation of lazy.md * WIP on translation utils * Normalize ru docs * Normalize other languages * some fixes * WIP on normalize/translate tools * add requirements.txt * [experimental] add es docs language as machine translated draft * remove duplicate script * Back to wider tab-stop (narrow renders not so well)
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Internal dictionaries
ClickHouse contains a built-in feature for working with a geobase.
This allows you to:
- Use a region’s ID to get its name in the desired language.
- Use a region’s ID to get the ID of a city, area, federal district, country, or continent.
- Check whether a region is part of another region.
- Get a chain of parent regions.
All the functions support “translocality,” the ability to simultaneously use different perspectives on region ownership. For more information, see the section “Functions for working with Yandex.Metrica dictionaries”.
The internal dictionaries are disabled in the default package.
To enable them, uncomment the parameters path_to_regions_hierarchy_file and path_to_regions_names_files in the server configuration file.
The geobase is loaded from text files.
Place the regions_hierarchy*.txt files into the path_to_regions_hierarchy_file directory. This configuration parameter must contain the path to the regions_hierarchy.txt file (the default regional hierarchy), and the other files (regions_hierarchy_ua.txt) must be located in the same directory.
Put the regions_names_*.txt files in the path_to_regions_names_files directory.
You can also create these files yourself. The file format is as follows:
regions_hierarchy*.txt: TabSeparated (no header), columns:
- region ID (
UInt32) - parent region ID (
UInt32) - region type (
UInt8): 1 - continent, 3 - country, 4 - federal district, 5 - region, 6 - city; other types don’t have values - population (
UInt32) — optional column
regions_names_*.txt: TabSeparated (no header), columns:
- region ID (
UInt32) - region name (
String) — Can’t contain tabs or line feeds, even escaped ones.
A flat array is used for storing in RAM. For this reason, IDs shouldn’t be more than a million.
Dictionaries can be updated without restarting the server. However, the set of available dictionaries is not updated.
For updates, the file modification times are checked. If a file has changed, the dictionary is updated.
The interval to check for changes is configured in the builtin_dictionaries_reload_interval parameter.
Dictionary updates (other than loading at first use) do not block queries. During updates, queries use the old versions of dictionaries. If an error occurs during an update, the error is written to the server log, and queries continue using the old version of dictionaries.
We recommend periodically updating the dictionaries with the geobase. During an update, generate new files and write them to a separate location. When everything is ready, rename them to the files used by the server.
There are also functions for working with OS identifiers and Yandex.Metrica search engines, but they shouldn’t be used.