ClickHouse New Releases and ChangeLog
Aug 30, 2017
It took a while for Yandex to respond to numerous community requests regarding release notes. But finally it's there. On August 21-st Yandex created a changelog file covering releases starting from 1.1.54245, and they keep it up to date so far.
Latest releases are focused on performance and stability. The list of performance improvements and bug fixes is impressive. As usual, latest RPM packages can be found in Altinity repository.
As a sidenote, I would like to highlight one interesting new feature: Dictionary engine.
Dictionary engine that converts dictionary to the table has been added in 1.1.54245 but there were bugs in initial implementation. Now it becomes useful. If you use dictionaries a lot Dictionary engine is very helpful. In particular, it is possible to create an introspection dictionary database, like:
create database dict engine=Dictionary;
Once created, all dictionaries can be viewed as tables with full SQL support. So you can select any column from the dictionary, quickly check the data types using 'desc' and so on. It also can be used as lookup tables for UI tools.
Note, that the 'opposite feature' already existed before. Using 'clickhouse' dictionary source it is possible to convert ClickHouse table to the dictionary. Not is is fully symmetric.