Performance and Optimizations

This section covers the following topics:

Topic	Description
Analyzer	Looks at the ClickHouse Analyzer, a tool for analyzing and optimizing queries. Discusses how the Analyzer works, its benefits (e.g., identifying performance bottlenecks), and how to use it to improve your ClickHouse queries' efficiency.
Asynchronous Inserts	Focuses on ClickHouse's asynchronous inserts feature. It likely explains how asynchronous inserts work (batching data on the server for efficient insertion) and their benefits (improved performance by offloading insert processing). It might also cover enabling asynchronous inserts and considerations for using them effectively in your ClickHouse environment.
Avoid Mutations	Discusses the importance of avoiding mutations (updates and deletes) in ClickHouse. It recommends using append-only inserts for optimal performance and suggests alternative approaches for handling data changes.
Avoid Nullable Columns	Discusses why you may want to avoid Nullable columns to save space and increase performance. Demosntrates how to set a default value for a column.
Avoid Optimize Final	Explains how the OPTIMIZE TABLE ... FINAL query is resource-intensive and suggests alternative approaches to optimize ClickHouse performance.
Bulk Inserts	Explains the benefits of using bulk inserts in ClickHouse.
Partitioning Key	Delves into ClickHouse partition key optimization. Explains how choosing the right partition key can significantly improve query performance by allowing ClickHouse to quickly locate relevant data segments. Covers best practices for selecting efficient partition keys and potential pitfalls to avoid.
Data Skipping Indexes	Explains data skipping indexes as a way to optimize performance.
Sparse Primary Indexes	Discusses sparse primary indexes in ClickHouse which are used to significantly accelerate query execution.
Query Profiling	Explains ClickHouse's Sampling Query Profiler, a tool that helps analyze query execution.
Testing Hardware	How to run a basic ClickHouse performance test on any server without installation of ClickHouse packages. (Not applicable to ClickHouse Cloud)
Query Cache	Details ClickHouse's Query Cache, a feature that aims to improve performance by caching the results of frequently executed SELECT queries.