The 5 most common ClickHouse mistakes and how to fix them

We went through hundreds of StackOverflow + Reddit threads on ClickHouse and after seeing the same pain points surface repeatedly, we wrote up the 5 most common ClickHouse mistakes engineers make in production: Expecting ReplacingMergeTree to deduplicate reliably. It does, but eventually and not synchronously Picking the wrong table engine (MergeTree when you need Aggregating/Replacing) Treating PRIMARY KEY like it enforces uniqueness (it doesn't and ORDER BY column order matters far more) Too Many Parts er