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Michael Matloka c2bc2fecd0
Use proper interval calculation in the funnel trends query (#5467) 
* Use proper interval calculation in the funnel trends query

* Add some comments

* Update `test_filter`

* Rework `NULL_SQL` to use CH `INTERVAL` too

* Fix week-based relative `date_from` support not existing

* Make use of `toInterval*` functions and inject less

* Add fallback for `date_from` in `ClickhouseSessionsAvg`
2021-08-06 11:29:35 +02:00
..
migrations Revert person.distinct_ids column (#5354) 2021-07-28 16:02:05 +03:00
models Implement workaround for reading person_distinct_ids (#5355) 2021-07-28 14:51:26 -04:00
queries Use proper interval calculation in the funnel trends query (#5467) 2021-08-06 11:29:35 +02:00
sql Use proper interval calculation in the funnel trends query (#5467) 2021-08-06 11:29:35 +02:00
test Remove process_event_ee (#4063) 2021-04-23 14:10:28 +02:00
views Improve cached_property typing (#5465) 2021-08-05 22:31:31 +03:00
__init__.py
client.py Update query metrics (#5460) 2021-08-05 13:12:52 +03:00
demo.py Populate a lone session recording for demo (#3128) 2021-01-29 14:28:55 +01:00
generate_local.py Generate local tests cases (#4874) 2021-06-25 12:38:04 -04:00
middleware.py Rename is_ee_enabled to is_clickhouse_enabled (#4216) 2021-05-13 16:56:54 +02:00
README.md Add --plan and --fake flags to migrate_clickhouse (#4160) 2021-04-29 15:40:12 +03:00
system_status.py Add running & slow queries to instance status dashboards (#4420) 2021-05-21 09:26:01 +03:00
timer.py Make timer safe (#5469) 2021-08-05 16:58:21 +03:00
util.py Make DDLs more friendly towards running on a cluster and cleanups (#5091) 2021-07-15 17:20:37 -07:00

README.md

Clickhouse Support (Enterprise Feature)

To accomodate high volume deployments, Posthog can use Clickhouse instead of Postgres. Clickhouse isn't used by default because Postgres is easier to deploy and maintain on smaller instances and on platforms such as Heroku.

Clickhouse Support works by swapping in separate queries and classes in the system for models that are most impacted by high volume usage (ex: events and actions).

Migrations and Models

The django_clickhouse orm is used to manage migrations and models. The ORM is used to mimic the django model and migration structure in the main folder.

Certain migrations (e.g. changing table engines) can be quite expensive and tricky, especially for deployments outside of cloud. To skip these steps during deployment setup, check for the CLICKHOUSE_INITIAL_MIGRATIONS environment variable.

If you need help in making them happen, ask for help from team deployments.

Queries

Queries parallel the queries folder in the main folder however, clickhouse queries are written in SQL and do not utilize the ORM.

Tests

The tests are inherited from the main folder. The Clickhouse query classes are based off BaseQuery so their run function should work just as the Django ORM backed query classes. These classes are called with the paramterized tests declared in the main folder which allows the same suite of tests to be run with different implementations.

Views

Views contain Viewset classes that are not backed by models. Instead the views query Clickhouse tables using SQL. These views match the interface provide by the views in the main folder.