ClickHouse Updates

Since our last update, ClickHouse grew up a lot, there were many new features and enhancements, some of them we reviewed in our blog, others are still waiting for somebody to tell a story about.

Most recently, ClickHouse added two new data types: Decimal and LowCardinality. Decimal data type was in the wish list for months. It is a must-have feature for financial calculations. LowCardinality data type isClickHouse path to dictionary compression. It is mostly useful for string columns, allowing to save on disk space and improve performance. It has been released in early September, and after improvements in following releases works fine.

Another feature that community was eager to see this year is support for UPDATE and DELETE statements. And it is there! ClickHouse often implements some functions in its own innovative way, and UPDATE/DELETE is not an exception. It does not turn ClickHouse to an OLTP datastore but works quite fine for data warehouse needs. We have written a detailed blog post to describe how it works.

And last but not least, ClickHouse dramatically improved compatibility with standard SQL. Not just it can now support standard JOIN syntax (well, almost), but standard SQL functions and data type aliases have been added for smoother use with BI tools like Tableau. The latest release of ClickHouse ODBC driver fixes remaining SQL-functions compatibility issues and Tableau works like a charm! Another important addition is that a few months ago ClickHouse fixed predicate push-down for SQL views, that makes it fully possible to use views as data marts for BI tools in order to hide date model specifics. We wrote about Tableau with ClickHouse already some time ago, and plan to revisit the topic soon again.

Aforementioned changes, as well as many other improvements, required quite a lot of work and testing, and sometimes we were disappointed by regressions in ‘stable’ releases. We still consider June ClickHouse release 1.1.54385 as the safest for production use if you do not need new features. In the last two months, new features finally stabilized, and we plan to tag October 18.14.10 release as the next stable for Altinity clients.

Even fall is coming to the end, we still have a lot to look forward to. On November 15, do not forget to join us at ClickHouse meetup in Amsterdam to learn why hundreds of companies across Europe, US, and China are adopting ClickHouse.

If you are interested in staying up-to-date with ClickHouse and Altinity, remember to check our blog, follow us on Twitter for the most recent news.