Interview Q&A / PostgreSQL

INTERVIEW Q&A · 69 QUESTIONS

PostgreSQL interview questions

Indexes, EXPLAIN, transactions and isolation, JSONB and the Postgres specifics backend interviews probe.

  1. What index types does PostgreSQL support, and why is my index sometimes not used?

    B-tree is the default and handles equality, ranges and sorting. GIN indexes values that contain many items, like JSONB, arrays and full-text search. BRIN is a tiny index for huge tables whose rows are stored in a natural order, like time-series data. The planner skips an index when a full scan looks cheaper, or when the query is written in a way the index cannot match.

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