DBA / Database

What is the difference between synchronous and asynchronous replication modes in AlwaysOn?

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How do you understand that these specific indexes on these columns will help achieve performant queries? How do you determine high selectivity?

Что такое Transaction ID Wraparound в PostgreSQL?

How was the PostgreSQL cluster organized? Replication scheme and fault tolerance?

How to implement partial transaction rollback (not full, but up to a certain point)?.

What are indexes in a database?

Tell us about the Always On High Availability technology in MS SQL Server.

Difference between a procedure and a function.

What is msdb in SQL Server?

What is a package of procedures? What does it consist of?

What is a CTE (Common Table Expression)? What are the advantages? Is the CTE materialized?

What is the difference between checkpointer and background writer?

What is a transaction and what are transaction isolation levels in PostgreSQL?

Are multiple DML operations executed in a single transaction in the procedure?

What can be done if an index is not used due to a function on a column?

Tell me about types of indexes. What are they and which ones have you used most often?

Translate: 'When will you ask him for help?'

What are window functions and how are they advantageous over aggregate functions?

What is mirroring in SQL Server and how does it differ from replication?

What index is suitable if the column has few unique values and many NULL values?