httk.store.backend.clickhouse.engine
====================================

.. py:module:: httk.store.backend.clickhouse.engine

.. autoapi-nested-parse::

   ClickHouse database construction for :class:`~httk.store.backend.sql.engine.Backend`.



Functions
---------

.. autoapisummary::

   httk.store.backend.clickhouse.engine.database


Module Contents
---------------

.. py:function:: database(cls, url, *, database = None)

   Build a ClickHouse-backed backend from a ``clickhousedb://`` URL.

   The URL uses the SQLAlchemy ``clickhouse-connect`` dialect, for example
   ``clickhousedb://default:@host:8123/my_database``.  ``database`` replaces the
   URL path when supplied.  The constructor always merges ``join_use_nulls=1``
   into the URL query and selects the ``bulk-fenced`` storage profile before any
   :class:`~httk.store.backend.sql.store.SqlStore` initialization occurs.

   :param cls: The backend class to instantiate.
   :param url: ClickHouse SQLAlchemy URL or URL string.
   :param database: The database name overriding the URL path, if supplied.
   :return: Connected ClickHouse backend wrapper using the bulk-fenced profile.
   :raises ImportError: If ``clickhouse-connect`` is not installed; install the
       ``httk-store[clickhouse]`` extra.
   :raises RuntimeError: If Keeper is unavailable, the server is too old, or
       ``join_use_nulls`` cannot be enforced.