Olga Silyutina- ClickHouse Applications in Data Analytics | PyData Yerevan July 2022 Meetup

Explore the capabilities of ClickHouse in data analytics, including OLAP scenarios, custom functions for analytics and machine learning, and optimized data storage and retrieval methods.

Key takeaways
  • ClickHouse is a column-oriented database mainly used for online analytical processing (OLAP) scenarios.
  • ClickHouse is not suitable for online transaction processing (OLTP) due to limitations in storing data and missing some data during insertion.
  • Custom functions in ClickHouse can be used for analytics and machine learning (ML) processes.
  • Multi-function in ClickHouse is a compact and easier-to-read version of the “CASE WHEN” function in SQL.
  • Engine, such as Merge Tree, is used in ClickHouse to store data and make it more efficient.
  • Partitions in ClickHouse are like folders that store data in a specific format, making it easier to retrieve and filter data.
  • Materialized views in ClickHouse can be used to create real-time aggregates based on select queries and can be faster than basic views.
  • Array functions in ClickHouse, such as group arrays and array enumerate, can be used for ranking and creating aggregates.
  • Low cardinality strings in ClickHouse can compress strings and make them more efficient.
  • ClickHouse supports replication and sharding, making it possible to store data on multiple machines and speed up processing.
  • ClickHouse has a unique exact function that calculates the unique amount of ad IDs in a table.
  • Approximate calculations in ClickHouse can be used to make calculations faster and more efficient.
  • Sample by index in ClickHouse can be used to get samples of data based on a specific column.
  • OLAP is a data discovery process that requires low latency and frequent queries.
  • ClickHouse has a lot of integrational engines, such as Kafka, MySQL, and JDBC.
  • Unique functions in ClickHouse can be used to calculate unique amounts of data in a table.
  • Materialized views can be used to transform data in a specific format and make it easier to retrieve and filter.
  • ClickHouse compared to relational databases has multiple indexes that can be used in different ways.