Does Clickhouse provide continuous (automated) aggregation functions/tables?

Question

I read that InfluxDB offers continuous aggregation features. Does Clickhouse provide something along those lines?

For example, I have certain real-time measurements arrive every couple seconds, sometimes multiple per second, but I am interested in frequently polling down-sampled measures, for example, summary stats of measurements per hour. Ideally, those aggregates should be calculated continuously server-side. I want to configure an aggregation that continuously updates my queries and generates views upon the arrival of new data or at specified intervals, such as every minute.

Is that possible?

Answer 1

Clickhouse materialized views you are looking for

• https://clickhouse.com/docs/en/guides/developer/cascading-materialized-views
• https://altinity.com/webinarspage/2019/6/26/clickhouse-and-the-magic-of-materialized-views
• https://altinity.com/blog/clickhouse-materialized-views-illuminated-part-1
• https://altinity.com/blog/clickhouse-materialized-views-illuminated-part-2
• https://den-crane.github.io/Everything_you_should_know_about_materialized_views_commented.pdf

SummingMergeTree & AggregatingMergeTree

they are able to downsample continuously the same time data is coming

• https://clickhouse.com/docs/en/engines/table-engines/mergetree-family/summingmergetree
• https://clickhouse.com/docs/en/engines/table-engines/mergetree-family/aggregatingmergetree

Postponed downsampling

• https://clickhouse.com/docs/en/engines/table-engines/mergetree-family/graphitemergetree
• https://kb.altinity.com/altinity-kb-queries-and-syntax/ttl/ttl-group-by-examples/