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Primary keys in ClickHouse are not what you're used to in other DBMSs. Picking a good primary key for your MergeTree tables is critical in optimizing query performance, so it's important to understand how they work. We include an explanation of the primary index and granules.

Rich Raposa
Director, Global Learning, ClickHouse

How Primary Keys Work in ClickHouse

Linux, macOS, FreeBSD

Using aggregate functions in a materialized view in ClickHouse can lead to surprising results if you don't define them properly. The AggregatingMergeTree table engine requires special column types for representing and storing intermediate (running) totals of aggregations like avg, max, min, uniq, count, and all the other aggregate functions in ClickHouse.

How to Compute a Running Aggregation in ClickHouse

Download ClickHouse, run the server, connect to it using the client, create a table based on a file in S3, ingest that data into your table, and write some queries.

Videos / How to

How to Get Started with ClickHouse

Rich Raposa Director, Global Learning, ClickHouse

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