Data Engineer

What table engines in ClickHouse do you know and have used?

What is the difference between WHERE and HAVING?

What should be paid attention to in terms of memory, speed, and correctness when parsing large XML files?

How does compression work in ClickHouse?

What is a Materialized View and how does it differ from a regular View?

Produce a list of costly bookings Question How can you produce a list of bookings on the day of [phone] which will cost the member (or guest) more than $30? Remember that guests have different costs to members (the listed costs are per half-hour 'slot'), and the guest user is always ID 0. Include in your output the name of the facility, the name of the member formatted as a single column, and the cost. Order by descending cost, and do not use any subqueries.

What is a DAG in Airflow, what does it consist of, and how does Airflow execute a DAG?

Regarding Python: how in-depth are your knowledge, and which libraries have you used?

How to pass data between tasks in Airflow?

How to evaluate the configuration for migrating one terabyte of data from PostgreSQL to ClickHouse?

Partitioning in databases: what is it for, how does it work?

How to read a 100-gigabyte file in Python?

How to view parameters or restrictions in ClickHouse?

What are the types of JOINs in SQL (logical and physical)?

What does OPTIMIZE do in ClickHouse and why shouldn't it be run thoughtlessly?

What is normalization and denormalization, when are they needed?

Tell me about your experience at X5: what did you do in the DWH area?

When is ThreadPoolExecutor appropriate?

How to reduce memory consumption of DataFrame in Pandas?

What should be checked if logs do not open (error 403)?